**2. Etiology of pulmonary valve disease**

	- Primary
		- Pulmonary stenosis
		- Pulmonary atresia
	- Secondary to surgical treatment of congenital lesions
		- Pulmonary regurgitation after tetralogy of Fallot repair
		- Homograft dysfunctions:
			- Following Ross procedure
			- Homografts used for reconstruction of the right ventricular outflow tract (RVOT):
				- Pulmonary atresia
				- Complex forms of tetralogy of Fallot
				- Truncus arteriosus

	- Carcinoid heart disease
	- Endocarditis
	- Pulmonary artery aneurysms
	- Tumors
	- Rheumatic heart disease


**4. Synthesis of rule-based logical model**

Combining FPGA [18] as a target hardware platform with hardware description language VHDL ensures high reliability, speed and safety. Additionally, it is possible to modify anytime the already running system, what has a practical sense. Direct implementation of concurrent logic controllers in FPGA is similar to rule-based realization based on classical sequence diagrams. Transition firings are synchronized with clock rising edge.

Control Interpreted Petri Net, which is the core for logical model, is a safe net. Places can be then implemented using simple flip-flops, as their marking is expressed by a binary value. Flip-flops amount (for places) using one-hot encoding is equal to the amount of places (and so to the amount of local states).

Logical model can be easy synthesized as reconfigurable logic controller. Logical model, derived from Control Interpreted Petri Net, is transformed into VHDL language according to some strictly defined rules [13]:

Model in VHDL is oriented on places and transitions. It can be simulated and synthesized. Synthesis is performed in form of rapid prototyping [5], what in modern methodology for digital circuits design allows for frequent verification (simulation, analysis) of developed system. Its main goal is to check, whether designed system works at all, but the circuit might be not optimized. Circuit optimization and minimization of resources usage are here out of scope, however they may be important in some fields [9, 18].

Logical model into VHDL model translation is done automatically using implemented software application. Generated VHDL file for considered drink production process is fully synthesizable.

Model for synthesis starts with input and output signals definition. Petri net places are defined as internal signals. By clock rising edge and active reset signal, some initial values are assigned to places, which correspond to initial marking of a Control Interpreted Petri Net. Additionally, by each clock rising edge places hold their heretofore marking.

For places the one-hot encoding was used (called also *isomorphic places encoding*), which is the most accurate (and the simplest) representation of logical model, however it can cause bigger resources usage. For each place one flip-flop is generated, which label corresponds to particular place etiquette. Flip-flop sets the *1* value, if a place contains token, otherwise it holds the *0* value. Additionally, one-hot encoding is recommended by implementation in FPGA circuits, and even seen as the most effective method for states encoding [23], i.e. in FPGA circuits of Xilinx [21], especially for small automata. It is also possible to extend the work to any other encoding.

Places marking can change after transitions firing. Conditions connected with transitions correspond to values of input signals and active marking of particular places. If a condition is satisfied, Petri net transition is realized, and thereby its input and output places change their marking (Figure 14).

```
if p1 = '1' and x1 = '1' and x4 = '0' then
 p1 <= '0';
 p2 <= '1';
 p3 <= '1';
 p4 <= '1';
end if;
```
**Figure 14.** The *t1* transition firing in VHDL model

188 Petri Nets – Manufacturing and Computer Science

FPGA for a reconfigurable logic controller.

so to the amount of local states).

to some strictly defined rules [13]:

edge and active reset signal,

a. Each place is an internal signal of *std*\_*logic* type, b. Each input signal is an input port of *std*\_*logic* type, c. Each output signal is an output port of *std*\_*logic* type,

marking of its input and output places,

active by active marking of corresponding places.

**4. Synthesis of rule-based logical model**

By introducing a subtle modification into Control Interpreted Petri Net, which regards initial marking removing from place *p14* (initial marking involves then only the *p1* place), the corresponding part of logical model and NuSMV model description is also changed. However, such a subtle change dramatically changes net behavior, and thereby designed logic controller behavior. Model checking of the same properties shows now another results. User receives multiple generated counterexamples indicating unsatisfied requirements. Places *p1* to *p12* are reachable, but it is not possible to reach active marking of further places. Next to last requirement is also not satisfied (*CTLSPEC AG (x13 -> AF !y12)*). Summarizing the report – an error occurs starting from transitions *t7* and t*13*, what confirms the fact, that it is indeed correlated with

When model checking process does not indicate any errors, it is then possible and advisable to focus on synthesizable code. Basing on logical model, model in hardware description language VHDL is built. The model is fully synthesizable and may be then implemented in

Combining FPGA [18] as a target hardware platform with hardware description language VHDL ensures high reliability, speed and safety. Additionally, it is possible to modify anytime the already running system, what has a practical sense. Direct implementation of concurrent logic controllers in FPGA is similar to rule-based realization based on classical

Control Interpreted Petri Net, which is the core for logical model, is a safe net. Places can be then implemented using simple flip-flops, as their marking is expressed by a binary value. Flip-flops amount (for places) using one-hot encoding is equal to the amount of places (and

Logical model can be easy synthesized as reconfigurable logic controller. Logical model, derived from Control Interpreted Petri Net, is transformed into VHDL language according

d. Each defined internal signal (Petri net place) takes an initial value, set by clock rising

e. Each place changes its marking according to defined rules; fired transition changes

g. Each output signal changes its value according to active places; output signals are

Model in VHDL is oriented on places and transitions. It can be simulated and synthesized. Synthesis is performed in form of rapid prototyping [5], what in modern methodology for

f. Input signals are not considered, as they are inputs to the logic controller,

additional initial marking (and actually the lack of it) of Control Interpreted Petri Net.

sequence diagrams. Transition firings are synchronized with clock rising edge.

Output signals are active by active marking of appropriate places, what is denoted as shown in Figure 15.

```
y1 <= p5;
y2 <= p6;
y3 <= p4;
...
```
**Figure 15.** Outputs assignment in VHDL model

Input signals value changes come from outside and are not modified inside VHDL model file. Their values are just read out by conditions related to transition firings.

Control Interpreted Petri Nets – Model Checking and Synthesis 191

Proposed novel approach to verification of reconfigurable logic controller programs and specification by means of Control Interpreted Petri Nets allows to detect even subtle errors on an early stage of system development. Rule-based representation of Control Interpreted Petri Nets in temporal logic is presented at RTL-level and is easy to formally verify using

Results of the work include the assurance that verified behavioural specification in temporal logic will be an abstract program of matrix reconfigurable logic controller. Hence, logic controller program (its implementation) will be valid according to its primary specification. This may shorten the duration time of logic controllers development process (as early discovered errors are faster corrected) and, consequently, save money (as project budgets

Furthermore, formal verification can improve the quality of final products, making them work more reliable. And even if a logic controller, already delivered to customer, will not work properly (it can always happen that some subtle error was overseen or that the specification was incomplete), it is possible to find error source using available techniques (verification, simulation, etc.). Then, some part of corrected system (or the whole system) may be one more

Future research directions include i.e. (but are not limited to) model checking of other forms of logic controllers specification and mechanisms for behavioural properties specification.

The author is a scholar within Sub-measure 8.2.2 Regional Innovation Strategies, Measure 8.2 Transfer of knowledge, Priority VIII Regional human resources for the economy Human Capital Operational Programme co-financed by European Social Fund and state budget.

[1] Adamski, M & Monteiro, J. L., From Interpreted Petri net specification to Reprogrammable Logic Controller Design, In: *Proceedings of the IEEE International*

*Symposium on Industrial Electronics*, 2000, Vol. 1, pp. 13 – 19.

time formally verified using extended requirements list and modified logical model.

model checking technique and to synthesize using hardware description languages.

**5. Summary and conclusions**

will not be exceeded).

**Author details**

*University of Zielona Góra, Poland*

**6. Acknowledgement**

Iwona Grobelna

**7. References**

VHDL file can also be simulated i.e. in *Active-HDL* environment [4]. Simulation confirms the proper functionality of designed logic controller (simulation results are presented in Figure 16).

It is then possible to perform logic synthesis and implementation, i.e. in *Xilinx PlanAhead* environment, in version *13.1* [21]. Sample resources usage for the *xa6slx4csg225-2* circuit from *Spartan6* family of *XILINX* [22] is listed in Table 3.

**Table 3.** Resources usage

**Figure 16.** Simulation results in *Active-HDL*

It is also possible to transform logical model into synthesizable code in Verilog language [9, 17], this aspect is however not discussed further in this chapter.


**5. Recent advances of skeletal radionuclide imaging and therapy**

It's well-known that the skeletal radionuclide imaging and therapy will have a prospective development in novel radiopharmaceuticals of skeletal imaging (18F-NaF) (Figure 14) and therapy (heavy ion Carbon-11 and boron neutron capture therapy (BNCT)) and advanced nuclear medicine equipments such as SPECT/CT, PET/CT and PET/MR. In routine clinical practice, a variety of new radiopharmaceuticals have been introduced in recent years. There are three commercial radiopharmaceuticals of Samarium-153-ethylenediaminetetramethylene phosphonic acid (153Sm-EDTMP), Rehnium-188-(Sn)-hydroxyethylene diphosphonate (188Re-HEDP) and Strontium-89 chloride (89SrCl2). 89SrCl2 is still the most widely used agent due to a longer physical half life (T½ = 50.5 days) and a pure beta-emitter playing an important role in radionuclide internal radiation therapy. 188Re-HEDP (T½ = 16.9 hr) obtained from 188W-188Re generator is cheap and convenient in clinical practice routine, with scintigraphic imaging of gamma rays in order to perform individual dosimetric studies, but 188W-188Re generator must be imported from other countries. 153Sm-EDTMP developed by our country is one of the radiopharmaceutical therapeutic agents and has relatively ideal physical, chemical and biological properties similar to 188Re except of slightly longer have-life (T½ = 40.4 hr). The 0.103-Mev gamma ray is suitable for imaging in vivo distribution. The benefit of the favourable clinical experience with 153Sm-EDTMP has been reported in several multicenter trials.

response is 1-12 months. The main toxicity of these radiotherapeutics is mild transient bone

Radionuclide seed such as 125I、103Pd、198Au implantation has been used in lots of clinical departments. Mostly 125I seeds (Figure 13) have been chosen as the proper one. Iodine-125 delivers a higher radiation dose to the patient due to the half life of 60 days and 125I seeds

marrow suppression.

multicenter trials.

**4.2 Radionuclide seed implantation**

planted have been used in the therapy of solid tumors.

Fig. 13. 125I seed is used in the therapy of solid tumor by implantation.

**5. Recent advances of skeletal radionuclide imaging and therapy**

It's well-known that the skeletal radionuclide imaging and therapy will have a prospective development in novel radiopharmaceuticals of skeletal imaging (18F-NaF) (Figure 14) and therapy (heavy ion Carbon-11 and boron neutron capture therapy (BNCT)) and advanced nuclear medicine equipments such as SPECT/CT, PET/CT and PET/MR. In routine clinical practice, a variety of new radiopharmaceuticals have been introduced in recent years. There are three commercial radiopharmaceuticals of Samarium-153-ethylenediaminetetramethylene phosphonic acid (153Sm-EDTMP), Rehnium-188-(Sn)-hydroxyethylene diphosphonate (188Re-HEDP) and Strontium-89 chloride (89SrCl2). 89SrCl2 is still the most widely used agent due to a longer physical half life (T½ = 50.5 days) and a pure beta-emitter playing an important role in radionuclide internal radiation therapy. 188Re-HEDP (T½ = 16.9 hr) obtained from 188W-188Re generator is cheap and convenient in clinical practice routine, with scintigraphic imaging of gamma rays in order to perform individual dosimetric studies, but 188W-188Re generator must be imported from other countries. 153Sm-EDTMP developed by our country is one of the radiopharmaceutical therapeutic agents and has relatively ideal physical, chemical and biological properties similar to 188Re except of slightly longer have-life (T½ = 40.4 hr). The 0.103-Mev gamma ray is suitable for imaging in vivo distribution. The benefit of the favourable clinical experience with 153Sm-EDTMP has been reported in several

 a b c Fig. 14 Normal image of 18F- Fluoride PET(a: 3D projection imaging b: coronal slice iamging: c: sagittal slice imaging)


**1.2. A little about hirudotherapy**

The number of compounds that have been discovered with anticoagulant potential in leeches and other bloodsuckers has become increasingly larger with the advent of transcriptomic analysis [11–13]. Nevertheless, the use of the animal itself has being also an alternative. Hirudotherapy, after many time, re-emerged in the 1970s. Leeches have been used with success in some kinds of microsurgeries and surgeries, as for example, in repair of lost limbs or still in plastic surgeries, where the animal helps in the blood fluid reestablishment [14, 15]. Hirudotherapy has also been used to treat soft tissue swelling and hematomas in trauma [16]. In the literature, you can find many reviews that report the use of this animal in different applications [14, 16–18]. On the other hand, a study where the use of leeches as an adjunct for the management of venous congestion after reconstructive surgery, realized with 87 patients, demonstrated that the morbidity associated with it should be considered, particularly the need for a blood transfusion [19].

There are even studies that demonstrate the opinion of the population regarding the use of the animal in surgery, of course that is not very comfortable for the patient. However, in general social cognition, the acceptance of hirudotherapy may not be very welcome at first, but provided with proper information and explanations, overall compliance of patients and caregivers can be improved and consequently result in superior outcomes in flap salvage [20].

Actually, no international protocols on leech therapy instructions have been established; some reported that leech application for a week is sufficient to get good results [21, 22]. However, it already was published in the literature, a guide of procedure for the use of leeches in surgical interventions [23].

#### **1.3. Hematophagous animals and role in hemostasis**

In all animals, the circulatory system exists in a perfect balance between coagulation (clot formation) and fibrinolysis (clot dissolution); in other words, to maintain blood in a fluid state, minimizing blood loss when the vascular system is injured. In this mechanism, endothelial cells and platelets are extremely important to form the hemostatic plug helping to arrest bleeding. First, after injury, circulating platelets bind to collagen in the exposed vessel wall and aggregate, and second, the clotting factors are activated in the coagulation cascade, resulting in the formation of a fibrin clot. Thus, hemostasis coagulation reactions and fibrinolysis are crucial for the proper functioning of the hemostatic system [24].

Hematophagous animals such as bloodsuckers (leeches, mosquitoes, and ticks) are rich sources of anticoagulant molecules; among them, clotting inhibitors, fibrinogenolytics, plasminogen activators, and platelet inhibitors, all are present in their fluids and secretions, with roles on physiological processes such as feeding, digestion, self-defense, etc. Bloodsuckers access the blood fluid through the wound made by specialized structures targeting blood coagulation components, specially thrombin, factor Xa and the prothrombinase and tissue factor/FVIIa complexes, as a strategy to maintain blood incoagulable over a relatively long period of time. These new anticoagulants from hematophagous animals have opened new perspectives in the scientific area for basic and applied researches, having applications in the therapeutic area, as anticoagulant medication. Therefore, hematophagous animals have been an excellent target for studies, including pharmacologists [3, 25, 26].


**Acknowledgements**

The authors gratefully acknowledge the tremendous effort and collaboration on the part of the USEPA Office of Water, the USEPA Office of Research and Development, and numerous state, federal, tribal, and contractor organizations that provide field, laboratory, and data analysis support for the National Lakes Assessment. The authors appreciate the constructive reviews of earlier drafts by D. Adams, F. John, and J. Markwiese. This chapter has been subjected to Agency review and has been approved for publication. The views expressed in this chapter are those of the author(s) and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency. Any mention of trade names, products, or services does not imply an endorsement by the U.S. Government or the U.S. Environmental Protection Agency. The EPA does not endorse any commercial products, services, or enterprises.

This work was authored by United States Government employees as part of their official duties. In view of Section 105 of the Copyright Act (17 U.S.C. §105) the work is not subject to U.S. copyright protection.

**107**

USA

**Author details**

Corvallis, OR, USA

\*, Steven G. Paulsen1

1 Office of Research and Development, US Environmental Protection Agency,

2 Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

3 National Research Council Senior Fellow, Corvallis, OR, USA

\*Address all correspondence to<EMAIL_ADDRESS>
provided the original work is properly cited.

, Philip R. Kaufmann1,2 and Alan T. Herlihy2,3

David V. Peck1

*Jewels across the Landscape: Monitoring and Assessing the Quality of Lakes and Reservoirs…*

*DOI: http://dx.doi.org/10.5772/intechopen.92286*


*Article* **Phenology and Potential Fecundity of** *Neoleucopis kartliana* **in Greece**

**Nikoleta Eleftheriadou 1,\* , Umar Lubanga 2 , Greg Lefoe 2 , M. Lukas Seehausen 3 , Marc Kenis 3 , Nickolas G. Kavallieratos 4 and Dimitrios N. Avtzis 1**

**Simple Summary:** The silver fly *Neoleucopis kartliana* Tanasijtshuk (Diptera, Chamaemyiidae) is the most abundant predator of the giant pine scale (GPS), *Marchalina hellenica* (Hemiptera, Margarodidae), and is considered a major factor in controlling GPS populations in Greece and Turkey. GPS has recently been detected in Australia. While generally not harmful to trees in its area of origin, GPS has a detrimental impact on pine trees in Australia and, therefore, needs to be controlled. As part of an evaluation of the silver fly for importation to Australia where it may be used as a biological control agent against GPS, we studied several aspects of the fly's life history, namely its seasonal occurrence and number of generations per year (phenology), its acceptance of artificial food sources as adult flies, and the number of eggs females produce over their lifetime. We found that the fly has three generations per year and feeds on all life stages of GPS (eggs, nymphs, and adults). Adults readily feed on a mixture of sugar and dry yeast, and females emerge with no or few eggs and develop more as they age.

**Abstract:** *Neoleucopis kartliana* Tanasijtshuk (Diptera, Chamaemyiidae) is the most abundant predator of the giant pine scale (GPS), *Marchalina hellenica* (Hemiptera, Margarodidae) in Greece. GPS is native to Greece and Turkey, where it is not considered a pest of *Pinus* spp., but a valuable resource for pine honey production. However, its introduction to new areas leads to high population densities of the scale, linked to declines in tree health and insect biodiversity. To assess the potential use of *N. kartliana* for a classical biological control program in Australia, we studied selected life-history traits of the silver fly, namely its phenology in northern Greece, feeding preferences of adult flies on artificial food sources, and potential fecundity of female flies. The silver fly was present in every site in northern Greece studied and was found to have at least three generations per year in this area. The fly's overall sex ratio was 1:1, and adult females emerged with no or few mature eggs in their ovaries, but egg production was exponential until at least the eighth day after emergence. These findings increase our knowledge about the biology of *N. kartliana* and aided in the evaluation of the silver fly as a classical biological control agent against invasive GPS in Australia.

**Keywords:** Chamaemyiidae; Margarodidae; voltinism; egg development

### **1. Introduction**

The family Chamaemyiidae (Diptera) is a group of small flies, commonly known as silver flies, whose larvae prey on sternorrhynchous Hemiptera, particularly adelgids,

**Citation:** Eleftheriadou, N.; Lubanga, U.; Lefoe, G.; Seehausen, M.L.; Kenis, M.; Kavallieratos, N.G.; Avtzis, D.N. Phenology and Potential Fecundity of *Neoleucopis kartliana* in Greece. *Insects* **2022**, *13*, 143. https://doi.org/ 10.3390/insects13020143

Academic Editor: Tibor Magura

Received: 6 December 2021 Accepted: 26 January 2022 Published: 28 January 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

aphids, mealybugs, scales [1,2], and psyllids [3]. The majority of chamaemyiids have one to three generations [4] and inhabit grassland, lowland, and montane habitats [5]. Larvae feed on adult soft-bodied hemipteran species, as well as on their nymphs and eggs [6], and they either pupariate on twigs and branches where their prey is found [7] or drop from the tree and pupariate in the soil [8]. Regarding the oviposition in Diptera, factors such as environmental temperature [9], quality and quantity of larval [10] and adult diet [11–13], mating [14], adult population density [9,12], age [13,15], photoperiod [16], and relative humidity [17] affect female egg production. Several Chamaemyiidae species have been successfully utilized in classical biological control programs throughout the world, e.g., Hawaii [18], New Zealand [19], and Chile [20,21]. Despite the potential of Chamaemyiidae as biological control agents against soft-bodied hemipteran species, the family has been understudied, and the biology and morphology of many species are not adequately described [1].

*Neoleucopis kartliana* Tanasijtshuk (Diptera, Chamaemyiidae) has been successfully used as a biological control agent against giant pine scale (GPS), *Marchalina hellenica* (Gennadius) (Hemiptera, Margarodidae) on the island of Ischia (Italy) [22]. GPS is a univoltine sap-sucking insect native to the eastern Mediterranean region, particularly Greece and Turkey. The scale feeds on *Pinus* spp., especially *P. brutia* and *P. halepensis*, but it can also infest *Abies cephalonica* Loudon (Pinales: Pinaceae) [23]. In its native range, it is considered an economically important insect for the apiculture industry rather than a major pest of *Pinus* spp., since it rarely causes tree mortality [24,25]. GPS excretes a sweet, glutinous substance called honeydew, which is collected and converted by bees into pine honey and represents 60–65% of the annual honey production in Greece [23,26]. Due to its importance to apiculture, GPS has been deliberately introduced to new areas of Greece and to the Italian island of Ischia [27], where, on several occasions, it became a pest, reaching high population densities associated with the decline in tree health and reduction in insect biodiversity on pines [25]. In late 2014, GPS was detected in Australia (Melbourne and Adelaide) on a novel host: the North American species *Pinus radiata* D. Don (Pinaceae), which represents 74.5% of the nation's softwood plantation estate [28]. Since its discovery, GPS population densities have increased dramatically, causing significant damage to untreated *P. radiata* in urban and peri-urban settings and threatening the pine forest industry of Australia [29]. The combination of GPS invading a novel environment without its natural enemies and the availability of suitable host trees increases the likelihood of GPS damaging susceptible trees and plantations if not controlled.

Recent research on the scale's natural enemy complex has shown that the silver fly *N. kartliana* is the most abundant predator among the natural enemies of GPS in its native range [29,30], suggesting the potential of *N. kartliana* as a classical biological control agent in Australia [29,31]. The species was previously studied by Gaimari et al. [32], who presented an extensive description of the morphology and biology of the silver fly in southern Greece. Here, we add to the knowledge about the species by (1) investigating the phenology of *N. kartliana* in northern Greece and (2) presenting novel data on the egg development in female flies (egg load or potential fecundity).

#### **2. Materials and Methods**

To study the phenology and occurrence of *N. kartliana* in northern Greece, we collected GPS-infested pine tree twigs and branches every 7–10 days between 6 November 2019 and 21 October 2021 from Kedrinos Lofos in Thessaloniki (57 sampling repetitions). No sampling took place between 4 March and 20 May 2020 because of the closure of the laboratory due to the COVID-19 pandemic. Additionally, to investigate the presence of the fly in different regions, we collected infested twigs and branches from eight sites in northern Greece: Stratoni-Stratoniki, Parthenonas, Katerini-Makriyalos, Pyrghetos-Tempi, Edessa (2–3 sampling repetitions each), Arnea, Alexandroupoli, and Thassos (1 sampling repetition each) (Figure 1). The samples were then transferred to the Laboratory of Forest Entomology (Forest Research Institute, Hellenic Agricultural Organization Demeter) at Vassilika

(Thessaloniki, Greece), where random samples of GPS-infested twigs were examined under a stereoscope Zeiss Stemi 508 (Zeiss, Oberkochen, Germany, magnification range 6.3–50×) to determine and count all silver fly and GPS stages present on the twig. The silver fly's developmental stages were evaluated according to the descriptions of Gaimari et al. [32] and the life stage of GPS according to those of Hodgson and Gounari [33]. Additionally, any species found on the infested branches were collected and kept in ethanol for future identification to further contribute to the description of the natural enemy complex of GPS. For a graphical analysis of GPS and *N. kartliana* phenology, the number of individuals per developmental stage and species was calculated as a percentage relative to other stages (*n* = minimum 100 for GPS). Demeter) at Vassilika (Thessaloniki, Greece), where random samples of GPS-infested twigs were examined under a stereoscope Zeiss Stemi 508 (Zeiss, Oberkochen, Germany, magnification range 6.3–50×) to determine and count all silver fly and GPS stages present on the twig. The silver fly's developmental stages were evaluated according to the descriptions of Gaimari et al. [32] and the life stage of GPS according to those of Hodgson and Gounari [33]. Additionally, any species found on the infested branches were collected and kept in ethanol for future identification to further contribute to the description of the natural enemy complex of GPS. For a graphical analysis of GPS and *N. kartliana* phenology, the number of individuals per developmental stage and species was calculated as a percentage relative to other stages (*n* = minimum 100 for GPS).

the fly in different regions, we collected infested twigs and branches from eight sites in northern Greece: Stratoni-Stratoniki, Parthenonas, Katerini-Makriyalos, Pyrghetos-Tempi, Edessa (2–3 sampling repetitions each), Arnea, Alexandroupoli, and Thassos (1 sampling repetition each) (Figure 1). The samples were then transferred to the Laboratory of Forest Entomology (Forest Research Institute, Hellenic Agricultural Organization

*Insects* **2022**, *13*, 143 3 of 11

**Figure 1.** Sampling locations for *Neoleucopis kartliana* in northern Greece. **Figure 1.** Sampling locations for *Neoleucopis kartliana* in northern Greece.

For the investigation of selected life-history traits of adult *N. kartliana*, all remaining GPS-infested branches potentially containing *N. kartliana* were transferred to wellventilated cages (60 × 60 × 60 cm) that were placed inside a climate chamber Termaks KB8400F (Termaks, Bergen, Norway) set to 23 °C and 60% relative humidity. In order to resemble the conditions from dusk to dawn, the climate chamber had a 16:8 h light:dark photoperiod with a gradual transition (lasting one hour) from 0% light to 100% light, and vice versa. The cages were inspected every 1–2 days in search of any *N. kartliana* adults. For the investigation of selected life-history traits of adult *N. kartliana*, all remaining GPS-infested branches potentially containing *N. kartliana* were transferred to well-ventilated cages (60 × 60 × 60 cm) that were placed inside a climate chamber Termaks KB8400F (Termaks, Bergen, Norway) set to 23 ◦C and 60% relative humidity. In order to resemble the conditions from dusk to dawn, the climate chamber had a 16:8 h light:dark photoperiod with a gradual transition (lasting one hour) from 0% light to 100% light, and vice versa. The cages were inspected every 1–2 days in search of any *N. kartliana* adults.

To determine the overall sex ratio, emerging *N. kartliana* adults were individually collected in small falcon tubes (5.5 cm length and 1.5 cm diameter), and their sex was identified by visual inspection of their genitalia according to the descriptions provided by Gaimari et. al. [32] using a stereoscope (Zeiss Stemi 508, magnification range 6.3–50×). To determine the overall sex ratio, emerging *N. kartliana* adults were individually collected in small falcon tubes (5.5 cm length and 1.5 cm diameter), and their sex was identified by visual inspection of their genitalia according to the descriptions provided by Gaimari et. al. [32] using a stereoscope (Zeiss Stemi 508, magnification range 6.3–50×).

To study the acceptance of artificial food sources as substitutes for GPS honeydew, which was presumed to be their natural food source [30] in the manner of other Chamaemyiid species [34], adults (*n* = 270) were gradually transferred to smaller cages To study the acceptance of artificial food sources as substitutes for GPS honeydew, which was presumed to be their natural food source [30] in the manner of other Chamaemyiid species [34], adults (*n* = 270) were gradually transferred to smaller cages (30 × 30 × 30 cm, mean number of adults per cage 15 ± 5) between 12 August and 5 October 2020. These individuals were provided with water (through a constantly soaked cloth strip laid loosely on a vial) and five different media simultaneously: (1) pine honey; (2) pine honey mixed with dry yeast diluted in water (2 mL:1 gr:100 mL); (3) water-diluted

pasteurized milk (50:50) provided through soaked cotton on a petri dish (8.5 cm diameter); (4) dry yeast diluted with sugar; and (5) raw, moist yeast mixed with sugar. Artificial food sources (4) and (5) were both provided in different rates (5–50%) and different liquidity states on cotton laid over petri dishes. All food sources were renewed every 2–3 days, and the behavior of the flies was observed twice per day (morning and noon) every 1–2 days. Cotton was used as a substrate for all artificial food sources to resemble the cotton-like wax excreted by GPS under which the honeydew is naturally produced.

To investigate the development of eggs in the ovaries of adult *N. kartliana* females over time (often called egg load or potential fecundity), branch samples from Kedrinos Lofos (Thessaloniki) were placed in cages and positioned near a natural light source for at least two hours. Thus, emerging flies were attracted to the light source, promptly collected in small falcon tubes (5.5 cm length and 1.5 cm diameter), and isolated in small containers (7 cm height and 5 cm diameter) in which they were provided with water and artificial food source (4) (see paragraph above for more details on the artificial food sources). The containers were placed in a climate chamber with the conditions as described above for infested branches. After 3, 6, or 8 days of rearing, females were killed by placing them into 99% ethanol for several minutes. Flies were then dissected under a microscope, and the eggs were counted either immediately after emergence (*n* = 25), or 3 (*n* = 35), 6 (*n* = 34), and 8 (*n* = 38) days after emergence. To be considered mature, eggs had to carry the stripe pattern typically visible on oviposited eggs [32], which was visible at 40× magnification, confirming that the eggshell was fully developed.

The influence of female age on the number of mature eggs in the ovary was analyzed using a negative binomial generalized linear model fitted with the *nb.glm* function of the MASS package [35] in R [36]. Female age was taken as a continuous independent variable and the number of eggs as the dependent variable. The Poisson distribution was not used because the residuals were overdispersed, as indicated by Pearson's chi-squared test, which was resolved by using a negative binomial distribution.

#### **3. Results**

*Neoleucopis kartliana* was present at all sites (Figure 1) in this study; however, its abundances varied widely between sites and over the season.

The fly was observed in every subadult developmental stage on the branches (eggs, larvae, puparia). Eggs were usually located inside or close to the cotton-like wax produced by GPS. Larvae were spotted either inside the ovisacs of GPS or close to other developmental stages (first, second, and third instar nymphs and adults). Puparia were found either inside the wax of GPS or in bark crevices, without the presence of GPS being necessary.

The data from Kedrinos Lofos (Thessaloniki) (*n* = 1124 individuals) suggested that, unlike its univoltine prey, the silver fly has three generations per year in northern Greece (Figure 2). The fly's eggs were found during all developmental stages of GPS. However, the graphical analysis of *N. kartliana*'s generations was based on the relative abundance of larvae and puparia only, as they are greater in size and could therefore be more easily detected compared to the eggs. *Neoleucopis kartliana* larvae were observed feeding on all developmental stages of GPS. In the first *N. kartliana* generation, larvae (young and mature) preyed mostly on GPS eggs and adults; in the second fly generation, larvae preyed on the first-instar nymphs of GPS; while in the third fly generation, larvae preyed on the secondand third-instar nymphs of GPS (Figure 2). Although *N. kartliana* larvae did not extensively prey on the third instar nymphs of GPS due to overwintering as puparia, early emerging larvae of the subsequent fly generation (first) were found preying on third instar nymphs of GPS and remained attached to their prey during the scale's ecdysis.

ecdysis.

**Figure 2.** Ratio (%) of different developmental life stages of (upper panel) *Marchalina hellenica* and (lower panel) *Neoleucopis kartliana* in Kedrinos Lofos (Thessaloniki) between November 2019 and August 2021. The area between the two dashed lines is one full year (2020), in which *M. hellenica* underwent one full generation and *N. kartliana* underwent three. **Figure 2.** Ratio (%) of different developmental life stages of (upper panel) *Marchalina hellenica* and (lower panel) *Neoleucopis kartliana* in Kedrinos Lofos (Thessaloniki) between November 2019 and August 2021. The area between the two dashed lines is one full year (2020), in which *M. hellenica* underwent one full generation and *N. kartliana* underwent three.

on third instar nymphs of GPS and remained attached to their prey during the scale's

A total of 6031 *N. kartliana* adults were sexed to estimate the overall sex ratio. With 50.8%:49.2% males:females, the sex ratio was almost 1:1, and no apparent difference in the sequence of emergence was observed between the sexes. A total of 6031 *N. kartliana* adults were sexed to estimate the overall sex ratio. With 50.8%:49.2% males:females, the sex ratio was almost 1:1, and no apparent difference in the sequence of emergence was observed between the sexes.

Data on the artificial food preference of adults could not be retrieved from this test, because the flies tended to frequently roam inside the cage. However, whenever flies were observed feeding, they were found on only two of the media provided. Adults introduced into the cage containing the different artificial food sources were observed to mainly feed on dry yeast diluted with sugar and, to a lesser extent, on the mixture of honey and yeast. When introduced into the cage, the flies roamed, inspecting the various artificial food sources. However, most flies soon gathered, attached their mouthparts, and fed only on the food sources mentioned above. Adults survived approximately two weeks in captivity with a sole providence of artificial food sources; however, this should not be considered Data on the artificial food preference of adults could not be retrieved from this test, because the flies tended to frequently roam inside the cage. However, whenever flies were observed feeding, they were found on only two of the media provided. Adults introduced into the cage containing the different artificial food sources were observed to mainly feed on dry yeast diluted with sugar and, to a lesser extent, on the mixture of honey and yeast. When introduced into the cage, the flies roamed, inspecting the various artificial food sources. However, most flies soon gathered, attached their mouthparts, and fed only on the food sources mentioned above. Adults survived approximately two weeks in captivity with a sole providence of artificial food sources; however, this should not be considered as the fly's lifespan, as it was not estimated individually, but rather in groups of 15 ± 5 adults.

as the fly's lifespan, as it was not estimated individually, but rather in groups of 15 ± 5 adults. There was a significant effect of female age on the number of mature eggs found in the ovaries (χ2 = 112.77; df = 1; *p* < 0.0001). Dissections showed that within 24 h of emergence, females had either zero (*n* = 21) or one to two (*n* = 4) eggs in their ovaries. However, until the eighth day after emergence, eggs matured in an exponential manner There was a significant effect of female age on the number of mature eggs found in the ovaries (χ 2 = 112.77; df = 1; *p* < 0.0001). Dissections showed that within 24 h of emergence, females had either zero (*n* = 21) or one to two (*n* = 4) eggs in their ovaries. However, until the eighth day after emergence, eggs matured in an exponential manner (Figure 3), and a mean of 25.7 eggs was found, with a maximum of 79 mature eggs found in one female.

**Figure 3.** Number of mature eggs in ovaries of *Neoleucopis kartliana* at different ages. The regression line indicates the predictions of the negative binomial generalized linear model that are backtransformed from the log scale. The gray area around the line shows 95% confidence intervals. **Figure 3.** Number of mature eggs in ovaries of *Neoleucopis kartliana* at different ages. The regression line indicates the predictions of the negative binomial generalized linear model that are back-transformed from the log scale. The gray area around the line shows 95% confidence intervals.

(Figure 3), and a mean of 25.7 eggs was found, with a maximum of 79 mature eggs found

#### **4. Discussion 4. Discussion**

in one female.

Results from this study support the proposed use of the predatory fly *N. kartliana* as a classical biological control agent to minimize the impact and spread of *M. hellenica* in Australia [17]. The silver fly has a high intrinsic growth rate, allowing it to undergo three generations per year in northern Greece, while its host is univoltine. It seems to prey indiscriminately on every developmental stage of the scale and was found to be present in all sites studied in northern Greece. Furthermore, potential fecundity of the fly was found to increase exponentially in the first eight days after emergence with an average of 25.7 eggs and females holding up to 79 eggs in their ovaries. Results from this study support the proposed use of the predatory fly *N. kartliana* as a classical biological control agent to minimize the impact and spread of *M. hellenica* in Australia [17]. The silver fly has a high intrinsic growth rate, allowing it to undergo three generations per year in northern Greece, while its host is univoltine. It seems to prey indiscriminately on every developmental stage of the scale and was found to be present in all sites studied in northern Greece. Furthermore, potential fecundity of the fly was found to increase exponentially in the first eight days after emergence with an average of 25.7 eggs and females holding up to 79 eggs in their ovaries.

*N. kartliana* appears to have at least three generations per year, confirming the observations of Gaimari et al. [32], who suggested that *N. kartliana* has two to three generations annually. Additionally, other species of the genus *Neoleucopis* have been described to be at least bivoltine, e.g., *N. pinicola* [37] and *N. atratula* [38,39]. Multivoltinism is an attribute that may considerably increase the chances of adaptation to novel environments because it imparts the capability of surviving and reproducing under various environmental conditions [40]. In a study on introduced biological control agents, Crawley et al. [41] found that insects with the highest intrinsic growth rates that typically also had other characteristics of r-selected species (smaller body size and faster maturity resulting in several generations per year) were more likely to establish successfully than those with a slower growth rate. Accordingly, Hokkanen and Sailer [42] suggested that there is a positive correlation between success in biological control and the agent's power of increase over that of the prey, supporting that, in general, successful natural enemies have two generations for every host generation. An example supporting this theory is the parasitoid *Aphytis melinus* (DeBach) (Hymenoptera, Aphelinidae), which was successfully used as a biological control agent against the California red scale, *Aonidiella aurantii*  (Maskell) (Hemiptera, Diaspididae), a worldwide pest of citrus [43]. According to Murdoch et al. [43], apart from prey specificity, another key feature leading to the success with this species appears to be the rapid development of *A. melinus* compared to the development of the pest, since the parasitoid has three generations for each scale *N. kartliana* appears to have at least three generations per year, confirming the observations of Gaimari et al. [32], who suggested that *N. kartliana* has two to three generations annually. Additionally, other species of the genus *Neoleucopis* have been described to be at least bivoltine, e.g., *N. pinicola* [37] and *N. atratula* [38,39]. Multivoltinism is an attribute that may considerably increase the chances of adaptation to novel environments because it imparts the capability of surviving and reproducing under various environmental conditions [40]. In a study on introduced biological control agents, Crawley et al. [41] found that insects with the highest intrinsic growth rates that typically also had other characteristics of r-selected species (smaller body size and faster maturity resulting in several generations per year) were more likely to establish successfully than those with a slower growth rate. Accordingly, Hokkanen and Sailer [42] suggested that there is a positive correlation between success in biological control and the agent's power of increase over that of the prey, supporting that, in general, successful natural enemies have two generations for every host generation. An example supporting this theory is the parasitoid *Aphytis melinus* (DeBach) (Hymenoptera, Aphelinidae), which was successfully used as a biological control agent against the California red scale, *Aonidiella aurantii* (Maskell) (Hemiptera, Diaspididae), a worldwide pest of citrus [43]. According to Murdoch et al. [43], apart from prey specificity, another key feature leading to the success with this species appears to be the rapid development of *A. melinus* compared to the development of the pest, since the parasitoid has three generations for each scale generation. However, recent research suggests that, when considering the multivoltinism of a biological control agent in a more holistic context of biological control programs, agent-related life-history traits play a rather minor role, compared to those related to how and when agents are released [44]. Nevertheless, we show here that the three generations of *N. kartliana* allow this predator to feed on all life stages of the scale, which would maximize its impact on *M. hellenica* populations. This

finding confirms those of previous studies on the feeding habits of Chamaemyiidae. For example, Satar et al. listed six *Leucopis* species that were observed preying on several developmental stages of aphids in Turkey [45].

We found that adult *N. kartliana* males and females emerged simultaneously, similar to *Leucopis argenticollis* and *L. piniperda* [46] (later both assigned to a new genus, *Leucotaraxis* [47]). Additionally, our data suggest that *N. kartliana* adults follow the Fisherian sex ratio (1:1) [48], which was also found for *N. pinicola* following laboratory rearing of field-collected puparia [37].

*Neoleucopis kartliana* adults survived for two weeks in captivity, successfully feeding solely on artificial food sources that consisted of water and a mixture dry yeast and sugar, as was also offered successfully to other silver flies [45]. The adults rejected or showed little interest in the alternative artificial food sources (pine honey, pine honey with dry yeast, milk, and a mixture of raw yeast and sugar). Flies generally require both sugar and protein to fully develop their reproductive systems and produce eggs, and different sources of protein can have various effects on longevity and fertility [12,17]. Although the traditional protein source used for dipteran species is milk powder, yeast could replace milk powder without a considerable loss of viability or egg production [12]. Chamaemyiidae flies are known to feed on honeydew produced by their host [49], which is a sugar-rich secretion of aphids and scale insects [50]. Because it is difficult and laborious to keep honeydew-producing scale insects alive on their host plants (especially when they are trees), replacing the natural food source with artificial ones can increase the efficiency of adult rearing. Gaimari and Turner [1] suggested the use of a mixture of honey and yeast as an artificial diet for adult *Leucopis* spp. While a mixture of sugar and yeast was used as an artificial diet for the *N. kartliana* adults in this study, our results do not contradict those of Gaimari and Turner, since *N. kartliana* adults did feed on the diet suggested by the authors but ultimately preferred the mixture of yeast and sugar. The comparative impact of the different food sources on the longevity and fecundity of *N. kartliana* remains to be studied.

*Neoleucopis kartliana* is oviparous, corresponding with most dipteran species [51]. Our results showed that females emerge with no or very few (one to two) mature eggs in their ovaries. The few eggs that were found in some freshly emerged females may have been developed in the few hours between emergence and dissection. Clearly, most of *N. kartliana*'s eggs mature after its emergence, making it a strongly synovigenic species (i.e., producing eggs throughout its adult life), which are typically relatively long-lived and dependent on external food sources, as shown for parasitoids [52]. The presence of mature eggs in an ovary is considered as the definitive characteristic for female sexual maturity [13], suggesting that there should only be a very short or no pre-mating period after emergence of females. This study showed that, over the span of 8 days, egg load increased exponentially to a mean of 25.7 eggs and a maximum of 79 mature eggs per female. Possibly, the eighth day after the emergence of *N. kartliana* is the transition point between sexually immature and mature female flies, similar to another Chamaemyiid species, *Leucopis palumbii* Rodani, that reaches sexual maturity at 8–10 days after emergence [53]. While this illustrates a promising intergenerational population growth rate, the silver fly's fecundity in nature has not yet been estimated, and it remains unclear if more eggs can be produced over a female's lifetime and if factors such as mating, food source, or environmental temperature affect egg production and, ultimately, realize the fertility of *N. kartliana*. Nevertheless, the maximum of 79 eggs produced by female flies in captivity signifies prospects for an increase in egg production above the current mean of 25.7 eggs if adjusted methods for rearing are practiced.

#### **5. Conclusions**

Phenological observations revealed that *N. kartliana* has at least three generations per year in northern Greece and is preying indiscriminately on every developmental stage of the univoltine GPS. According to laboratory observations, the silver fly is oviparous and produces eggs without mating occurrence, and can survive for about two weeks in captivity when provided with artificial food sources consisting of water, sugar, and dry yeast. Adult females emerge with no or very few mature eggs in their ovaries, after which egg production increases exponentially until at least the eighth day after emergence. This investigation of the silver fly's life-history traits helps to better understand its biology and contribute to its evaluation as a classical biological control agent of the invasive GPS in Australia. However, research on the fly's prey specificity, mating behavior, rearing, as well as definite lifespan and egg load throughout its lifespan remains to be conducted in order to further understand its behavioral ecology and safe use as a biological control agent and to optimize its chances of establishment, as other Chamaemyiid biological control agents have failed to establish in Australia [54].

**Author Contributions:** Conceptualization, D.N.A., N.E., M.L.S. and M.K.; data curation, N.E.; data analysis, N.E., D.N.A. and M.L.S.; writing—original draft, N.E.; writing—review and editing, D.N.A., M.L.S., M.K., G.L., U.L. and N.G.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Agriculture Victoria, Forest and Wood Products Australia, and Australian pine plantation growers under agreement number PNC489-1819.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Data are contained within the article.

**Acknowledgments:** We would like to thank the Editor and all three anonymous reviewers for their valuable comments on the manuscript that improved the clarity and cohesion of our work, and we thank Mary Chatzitriantafillou for providing interpretation suggestions and aiding with figures.

**Conflicts of Interest:** The authors declare no conflict of interest.

### **References**


*Case Report* **Two Cases of Feigned Homicidality: Assessing the Third Dimension in Homicidal Threats**

**Pavan Madan 1,\*, Alexander Graypel 2 and Alan R. Felthous 3**

	- 3 Department of Neurology and Psychiatry, Saint Louis University, Saint Louis, MO 63103, USA
	- **\*** Correspondence<EMAIL_ADDRESS>
**Abstract:** Although data and research on the topic are lacking, the phenomenon of feigned homicidality in short-term hospitalization appears to have increased in recent years. Inpatient psychiatrists not only assess the seriousness of homicidal threats, but also whether such threats are authentic. However, specific literature and diagnostic manuals provide virtually no clinical guidance for this. The authors present two case examples of homicidality feigned for self-serving purposes that had little to do with hostility against the would-be victim. They recommend an approach to assessment that first takes any threat of homicide seriously, and involves an attempt to assess the seriousness of the threat and risk of harm. Secondly, if feigned homicidality is suspected, clinicians can methodically assess for this using criterion that have been applied to the assessment of malingering.

**Keywords:** homicidal; case series; malingering; feigned; threat; risk assessment; psychiatric evaluation

#### **1. Introduction**

The professional literature on assessment of a patient's verbal threat to kill concerns a determination as to whether the homicidal statement is only a fantasy, not likely to be carried out, or a serious intention with a realistic potential for a lethal or injurious outcome. Not usually included in such discussions is a third possibility: the verbal statement is made to achieve a self-serving but non-homicidal goal. In many cases, the possibility of feigned homicidality must be considered together with fantasized and planned homicide when assessing risk.

Sixty years ago, it would have been rare for anyone to threaten to kill another person simply to gain hospital access. Times were different. Involuntary hospitalization in a mental facility could extend for months or years. Homelessness of the mentally ill was limited, and addiction to street drugs was not as prevalent. In recent years, increasing reference is made to the patient who achieves hospitalization for "three hots and a cot", rather than for psychiatric treatment of symptoms of mental illness [1]. Without mentioning feigned homicidality specifically, literature on malingering recognizes hospitalization as a goal in some cases. However, feigned homicidality seems to be becoming a more frequent strategy for gaining hospitalization for various reasons.

Patients often have alternative motives for entering hospitals, such as the motive to detoxify comfortably from addicting drugs, to seek sedative medications, to obtain lodging that is more comfortable than a homeless shelter, or to avoid jail detainment. Intended escape from destructive conditions and circumstances is a positive motivation that is adaptive and supportive of mental health. Once detoxified, the addicted patient no longer claims suicidal or homicidal thoughts and may even admit to having fabricated such thoughts in order to gain hospitalization. Within a few days, they are eager to return to the situation from which they came without considering rehabilitative measures.

In this article, we present two cases of feigned homicidal ideations to gain access to hospital. We then discuss the recommended evaluation of verbal threat, assessment of risk,

**Citation:** Madan, P.; Graypel, A.; Felthous, A.R. Two Cases of Feigned Homicidality: Assessing the Third Dimension in Homicidal Threats. *Healthcare* **2022**, *10*, 31. https:// doi.org/10.3390/healthcare10010031

Academic Editors: Francesco Sessa and Mariano Cingolani

Received: 10 November 2021 Accepted: 21 December 2021 Published: 24 December 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

differentiation from pseudologia fantastica, and approach towards cases with suspected feigning of homicidal ideation. We hope that the cases and the discussion provide the reader with an understanding of how such cases may present at different stages of mental health treatment in a hospital, and when feigned homicidality is suspected, how the providers can perform a reasonable assessment to establish a diagnosis and treatment plan. We use two unrelated cases as examples. Both cases are discussed at length below, and their main findings are later summarized in Table 1.

**Table 1.** Summary of pertinent findings in the two cases that point towards a possibility of feigned homicidal ideations.

#### **2. Case Examples**

#### *2.1. CASE I*

Mr. A was a Caucasian man in his forties with a history of chronic medical conditions and multiple emergency room (ER) visits for chest pain and alcohol intoxication. He was homeless and unemployed, having recently lost his job as a cook. He had no documented past psychiatric history. He was brought to the ER by emergency medical services after complaining of chest pain and possible overdose. Mr. A reported to the ER physician that he was having suicidal ideation and planned to drink excess amounts of alcohol, hang himself, or shoot himself with a gun, which he said he did not possess. The patient presented symptoms of depressed mood, hopelessness, helplessness, and decreased interest in things as well as decreased sleep. He reported a pending DUI charge, regular alcohol use with blackouts, buildup of tolerance, and withdrawal tremors. He denied symptoms consistent with mania. He denied hearing voices or having visions and showed no signs of response to internal stimuli.

The patient had hypertension, bilateral upper extremity neuropathy, COPD, and angina. He also reported a history of a stroke 6 years earlier, which led to loss of function in his right arm and left leg. Per neurology consultation, this stroke was very unlikely, and the patient had no current stroke-related deficits.

On the mental status examination, he was hostile and irritable during the interview. He described his mood as "very sad at this point". Thought content included suicidal ideation with a method. He denied experiencing voices or visions. He was alert and oriented to place and time and appeared to have medical decision-making capacity, but he refused to cooperate with the mini-mental status exam.

On the first day after admission, the patient said he slept poorly; however, the nurses reported that he had slept for 8 h. He showed no withdrawal symptoms. He continued to express suicidal ideation without any plan. He denied having homicidal thoughts towards anyone. On the second day, he was angry over the food, the nurses, other patients, the medical students, and at the unit in general. He did not attend any of the group therapy sessions, was aggressive during interviews, and reported his mood to be "terrible". He also started complaining of voices telling him to hurt himself; however, he was never seen responding to internal stimuli.

Over the next few days, the patient continued to report suicidal ideation with various methods, ranging from hanging to not having a method. He became more social and attended some groups. During one interview, he revealed that he had homicidal ideation towards five individuals outside the hospital, but he declined to provide any information about them. He displayed narcissistic traits, especially when criticizing the hospital food, often saying "I can cook around these fools". He described his desire to work in a fancy restaurant one day, which was inconsistent with his talk of abruptly bringing about his own death.

When asked for consent to talk to his family, he said that he would allow his doctors to talk to his brother, but only after he talked with him first. Immediately after sharing that his brother was an important government employee, he described elaborate revenge fantasies towards three individuals, who he said had wronged him in the past. One of the individuals was a previous employer, the other individual was his ex- girlfriend's mother, who he said he wanted to torture and strangle. This was to retaliate for causing him and his girlfriend to break up. The third individual used to be his best friend, but then this man impregnated his ex-girlfriend. He claimed that he thought this because he knew his friend's blood type and that of his own, and believed that the baby's blood group corresponded with that of his best friend and his ex-girlfriend's, and therefore, that the baby must have been fathered by the other man. There were two more people who the patient said he had thoughts of killing, but he refused to tell his treatment team about them. He exclaimed dramatically, "I will tell you when the time is right!" Over the next few days, Mr. A attended all of the groups, ate all of his meals, and was cooperative with medication.

Mr. A spoke more about his "revenge plans", which were very unrealistic and sounded like a revenge fantasy movie. He said that he did not expect to get caught because he was "just too good". One of the authors spoke with Mr. A's brother, who confirmed the patient's history of alcoholism. His brother was unsure about any "revenge plans" and could not confirm any of the events that the patient described. However, he shared that his brother had been emotionally hurt by his ex-girlfriend in the past, but he had not heard about any paternity situation. His brother said that the patient had a good support system on the outside and many family members; however, many of them have children, and they did not want Mr. A around them when he was drunk. Once Mr. A becomes abstinent, he would have their full support.

Mr. A then developed plans to enter an alcohol rehabilitation program close to home so he could spend more time with his family. When asked again about homicidal thoughts, he described them but was inconsistent and less detailed than before. He again talked about his ex-girlfriend, but this time, he appeared to have forgotten what he had reported to his treatment team a few days earlier and said that he was very depressed because his ex-girlfriend had died in a car accident with the baby still inside of her. There were several inconsistencies in his story, and his brother also confirmed that the ex-girlfriend was still alive despite the patient having said that she died in a car accident. Other homicidal thoughts continued to be vague, and he continued to alter the number of people he wanted to kill. Citalopram and trazodone were discontinued and replaced with mirtazapine to help with his chronically poor sleep, appetite, and mood. The patient placed a telephone call and planned to go into rehabilitation.

A few days later, the patient asked the physician if he could have a doctor's note confirming his stay in the hospital with the exact dates of hospitalization. He said he needed the note because he had missed two court cases that were scheduled two days following admission, and that he was unable to attend them as a result of being in the hospital. He added that this had nothing to do with the reason that he presented to the hospital.

The next day, the patient said his homicidal thoughts were only towards two people. He was still irritable on the unit and complained about the food and other patients. However, he was social with his peers, laughing, playing cards, and joking at times.

As the time neared the patient's rehabilitation intake date, he began to deny suicidal ideations. He continued to express homicidal ideation, but these thoughts were assessed as likely revenge fantasies or malingering given their inconsistencies and vagueness.

The patient was contacted by one of the authors 3 months after his discharge to see how he was doing. He said that he was doing great and maintaining his sobriety. When asked about his homicidal thoughts, the patient said, "That's the furthest thing from my mind".

The diagnosis of feigned homicidality was based on (1) inconsistent history over time; (2) inconsistency between Mr. A's account from that of his brother; (3) evidence of a clear external incentive for hospitalization; (4) no clear plan for homicide or access to a weapon, and; (5) lack of cooperation with the diagnostic assessment.

#### *2.2. CASE 2*

Mr. B was a 46-year-old African American divorced male, with a history of schizoaffective disorder and hypertension, who presented to the ER with complaints of "hearing voices and feeling suicidal and homicidal". The patient told the ER physicians that he was hearing voices telling him to jump off a bridge. He said that, one week before, on being commanded by voices, he had jumped off the balcony from his second floor and suffered minor knee abrasions. When the psychiatry resident interviewed Mr. B, he said that the voices were telling him to jump off the roof of his two-story apartment (but he did not mention the bridge).  He said that he was upset with his sister due to a will dispute, which arose after the death of their mother 2 years previously. He alleged that his sister took money from the inheritance to open a business, and that this incident had infuriated all of his siblings. Mr. B stated that he did not see her on a regular basis, but knew where she lived and how to reach her.

Mr. B reported several depressive symptoms including feeling depressed, poor sleep, poor appetite, 15 lbs. weight loss, feelings of loneliness, hopelessness, anger at God for taking away his mother, poor concentration, and lack of interest in pleasurable activities. He also reported feeling nervous. He reported feeling paranoid that "people are out there to get me".

Mr. B reported that he had been previously diagnosed with schizophrenia, bipolar disorder and schizoaffective disorder. He stated that he first started hearing voices at the age of 32 years, after the death of his father. He had been taking antipsychotics off and on for the past several years. Previous psychiatric hospitalization revealed the diagnoses of cannabis abuse, cocaine abuse, and substance-induced mood and psychotic disorders. The patient reported having had multiple psychiatric hospitalizations in the past, including one in the same hospital as the current presentation. He reported to have made one suicide attempt 4 years earlier by overdosing on his medications "because the voices told me to do so" (he did not report any suicide attempt 1 week previously).

The patient reported being treated with oral as well as long-acting risperidone injection during his previous hospital stay, along with sertraline and trazodone. These were confirmed in the medical records obtained from another facility.

Mr.  Mr. B said that he lived by himself in an apartment. He did not work and received financial assistance from the state for his disability, i.e., schizophrenia and bipolar disorder.

From previous hospitalization records, the patient had been admitted to this hospital with complaints of hearing voices that told him to kill himself in the context of recent use of alcohol, cocaine, and marijuana 2 months before this presentation. The next day, when it was discovered that a female patient on the unit was related to him, the patient was told that he had to be transferred to another hospital. At this point, the patient became upset and said that he was not hearing voices anymore, nor was he feeling suicidal or homicidal and did not want to go to another hospital.

Mr. B said that he was no longer hearing voices, but he continued to feel suicidal as well as homicidal (against his sister). He denied having any means with which he could kill her, and this was the only factor that prevented him from killing her. When questioned regarding the possible consequences of killing his sister, Mr. B responded that he was confident that he would not go to jail because his entire family would support him in his act. When gently confronted with the idea that his family support may have little to do with the legal accountability of his behavior, he became irritable, and the conversation could not be pursued further. His affect remained flat throughout this interview.

On the second day of hospitalization, Mr. B was seen to be out and about on the unit, interacting with peers and staff members and attending all group therapy sessions, but continuing to express homicidal ideation.

On the third day, the patient's homicide risk was assessed using the method suggested by Borum and Reddy [2]. (1) Attitudes: The patient did not have any history of prior violence. His family history did not support violence. He continued to pray. (2) Capacity: He denied having considered a method of homicide, so capacity could not be adequately assessed. He said, however, that he was going to move to Florida (from the Midwest) to remove himself from his sister, which would decrease opportunity/capacity. (3) Threats: Although Mr. B had complained to his sister and her coworker in the past about her stealing the money from their inheritance, he denied having threatened her, having been physically aggressive towards her, or having done anything to prepare to harm her. (4) Intent: He denied current intent. (5) Others: He said that his family may support him if he killed her, as they were also angry at her for stealing, but he did not feel that they would join him or encourage him in doing so. (6) Noncompliance: He appeared to be compliant with risk reduction measures. Additionally, he denied access to a weapon. He provided his physician verbal permission to contact his sister.  From this assessment, the final impression was that the risk of violence was low and that his physicians did not have sufficient reason to either notify police or pursue involuntary hospitalization. After his sister was contacted and notified by the resident about his expressed feelings and violent thoughts, Mr. B was discharged from the hospital to enter a substance abuse inpatient rehabilitation facility.

After the patient's discharge, some of his belongings were discovered in the possession of the female patient on the unit. When she was confronted, she confessed that she was Mr. B's "significant other" (with a different last name) and they had arrived in the ER together but had not disclosed their relationship (as they had not been allowed to stay together on the same unit during their previous visit to this hospital). Moreover, they had decided to simultaneously feign similar psychiatric symptoms of hearing voices and feeling suicidal and homicidal to gain admission because they were homeless and needed a place to stay for a week. This confession provided a rare confirmation of the suspicion that the symptoms of homicidality were feigned for external incentive. In retrospect, the Borum factors proved to be helpful in accurately evaluating low risk of harm in this case.

Homicide risk assessment supported feigned homicidality based upon the following. (1) The patient was known to feign similar symptoms for a clear external incentive (housing) during the previous two visits; (2) he was currently experiencing an acute need for housing; (3) he had not been compliant with his medications for several months but had not "relapsed" until 3 days previously; (4) Mr. B denied knowing the female patient, with whom he had presented to the same ER during his past two visits; (5) the patient did not have easy access to a weapon; (6) the patient had planned to move to Florida after 2 weeks; and (7) he was not experiencing acute psychotic symptoms. The homicide risk was assessed to be low, and the patient was discharged from the ER after medical stabilization for hypertension.

#### **3. Discussion**

The cases highlight several important clinical points towards the assessment of feigned homicidality. Keeping these two cases in mind, we would now like to discuss how to

differentiate feigned homicidality from pseudologia fantastica, how to evaluate a verbal threat, how to assess homicidal risk, and eventually how to conduct further assessment when feigned homicidality is suspected We then discuss the duty to protect and the use of a multidisciplinary approach in the management of such cases.

#### *3.1. Differentiating Feigned Homicidality from Pseudologia Fantastica*

Today, pseudologia fantastica is not to be found in the DSM 5 [3], although factitious disorder is, earlier known as Munchausen's Syndrome. The original story of Van Munchausen was of a legendary baron who told fanciful false episodes of adventure. Kraepelin referred to Munchausen when describing psychological processes of "hunter traits", which he considered within the realm of normalcy. Delbruck [4] was the first to use the term "pseudologia fantastica" in 1891 and describe it as a phenomenon that is observed in normal, characterologically disturbed, as well as mentally ill individuals. It exists on a continuum between lying with full awareness of the statement's untruths and delusions where the unreality of the belief is not appreciated. In pseudologia fantastica, the subject's vulnerability to self-deceit from his own falsehoods can vary and fluctuate.

In summarizing the features of pseudologia fantastica from the literature, Birch and colleagues [5] list "excessive, impulsive lying" that usually begins in adolescence and then persists. The lies are fanciful, easily shown to be falsehoods, and are self-destructive. Motives are internal such as wishful fantasy, and not externally motivated, such as to gain materially or avoid punishment. Pseudologia fantastica involves impaired reality adherence but not to the degree found in delusions. More recently, Thom et al. [6] described the phenomenon of pseudologia fantastica as a state of chronic lying/storytelling that is dramatic, seeking admiration or sympathy, and out of proportion to the obvious benefit.

#### *3.2. Evaluating the Verbal Threat*

Regardless of whether a homicidal threat is initially thought to be idle or serious, feigned or authentic, it should be assessed. Not many years after the California Supreme Court's Tarasoff ruling in 1976 [7], Appelbaum [8] provided a three-step approach for dealing with homicidal threats that remains today as prudent guidance. Although the screening is derived from early Tarasoff-like case laws, this three-step approach seems self-evident in its practicality for any clinical risk assessment including the risk of suicide assessment: (1) Gather data that are relevant to the assessment of dangerousness. (2) Based upon this data, make a determination of dangerousness and select a course of action and (3) implement this plan. By case examples, Appelbaum illustrates how clinicians overreact and issue unnecessary warnings following insufficient assessment of the threat. Here, it is suggested additionally that assessment informs the action to be taken not only by a methodical determination of the patient's level of seriousness and dynamics of the risk, but also by determining whether the threat is authentic or feigned. Whether a verbal threat of homicide is feigned is also relevant to its seriousness.

In theory, as with risk assessments in general, probability predictions that a homicidal threat will be carried out should be more comprehensive than just to answer forced, dichotomous questions such as whether to hospitalize or whether to issue protective warnings [9]. To address such protective actions to be taken, the assessment of the risk, whether associated with a verbal threat or not, should incorporate four inquiries [8]: (1) Is the patient dangerous to others? (2) Is the danger due to serious mental illness? (3) Is the danger imminent? and (4) Are potential victims of the danger reasonably identifiable? The present discussion focuses only on those patients who would be hospitalized either because the danger is due to serious mental illness in need of intensive treatment, or the danger is imminent and no less restrictive means of protection are available.

Whenever practical, it is helpful to explain to the patient at the beginning of the clinician–patient relationship the terms of confidentiality, including the possible exception of protective warnings. Assessment of the potential for externally directed violence should then proceed along with the assessment of the potential for self-harm and suicide. Family

members, previous treatment providers, and other collateral sources should be contacted where doubt exists about the seriousness of an expressed threat [6]. As with the assessment for suicide, any initial threat of homicide is taken seriously and evaluated accordingly, even when the clinician suspects that the threat is feigned.

#### *3.3. Assessment of Risk*

With the realization that research on assessing the seriousness of homicidal threats is much less developed than research on the risk of aggressive behavior in general, the clinician can usefully apply the guidelines provided by Borum and Reddy [2] for assessing the seriousness of the risk of homicide. Practical, methodical, and literature-based, the Borum and Reddy factors are summarized with the acronym ACTION: (1) Does the patient hold Attitudes that support violence as a method to deal with the interpersonal conflict? (2) Does he have the Capacity to carry out the threat? There are several components to capacity: availability of the intended victim, availability of means (e.g., weapon), and physical capacity as well as mental capacity. (3) Has he already crossed Thresholds in the direction of violating the victim's autonomy and privacy or of preparing to act violently against the victim (e.g., stalking, verbal threats, inappropriately accosting the victim at the victim's place of employment)? (4) Does the patient have a serious Intent behind the threat? Is it conditional and will only be carried under specific conditions that are not yet in place? (5) Do the attitudes and reactions of significant Others support violent responses? Conversely, do family members and close friends favor non-violent approaches to interpersonal problems? (6) And finally, is the patient Non-compliant with attempts at risk reduction, such as following treatment recommendations, helping to identify and contact the victim (if a protective warning is indicated), and neutralization of firearms. The reverse, or absence of the Borum factors, can be considered as potentially protective against enactment of the threat. Ultimately, the determination of high, medium, and low risk for violence following a verbal threat of homicide is a matter of clinical judgment, and not numerically quantitative.

#### *3.4. Assessment of Feigned Homicidality*

If the suspicion of feigned homicidality persists even after the homicidal threat has been assessed, it should be further explored. Psychiatrists need more than just a gut feeling to determine if the patient is lying. Psychiatrists must be aware of their countertransference while conducting further assessment. Guidelines for malingering can be useful in this regard, with malingering being "the intentional production of false or grossly exaggerated physical or psychological symptoms, motivated by external incentives such as avoiding military duty, avoiding work, obtaining financial compensation, evading criminal prosecution or obtaining drugs" [3]. The clinician is challenged with a dearth of professional literature on the assessment of feigned homicidality and by the patient's disinclination to explicitly share his motivation for malingering, which would of course defeat the purpose.

Methods for the assessment of malingering in general should be useful in detecting feigned homicidality [1]: namely, inconsistencies (1) in the patient's self-reports of homicidal thoughts (threats); (2) between what the patient reports and what others observe and report; (3) in observations concerning the "symptoms" themselves, in this case the patient's potential for homicide; (4) between the patients' self-report and performance on psychological tests (or mental status exam); and (5) in the patient's report of homicidal threats or thoughts and how actual threats with serious intent are manifested. The task is challenged by the fact that the patient only needs to express homicidal ideations to arouse concern; he need not necessarily malinger a complex condition such as psychosis.

The guidelines proposed by Borum and Reddy [2] are useful in the assessment of risk of homicidality. As in the case of Mr. B, they proved useful in highlighting the discrepancies in his history and the assessment of the overall risk. Moreover, due to safety concerns, it is often difficult to entertain the possibility of feigning symptoms when the risk of homicidality is assessed to be high. However, when the risk is determined to be low, the third dimension, i.e., feigning of homicidality can be further explored, as highlighted in the case of Mr. B. Although it is not always possible to gain knowledge of the potential incentives, an active search may prove to be useful. The areas that may assist in the determination of malingering include (1) a thorough history from the patient—it may even be helpful to periodically reassess the patient and be cognizant of any discrepancies in the narration over time; (2) thorough collateral information—this can prove to be very helpful, especially when obtained from multiple sources; refusal to provide any collateral source and lack of cooperation during the diagnostic or treatment process may also point towards an ulterior motive; (3) an active inquiry regarding the pertinent motives—financial constraints, lack of housing, and legal issues are especially prevalent in certain areas; and (4) legal inquiry—certain states provide an easy to access legal history of their clients, which may disclose any legal matter that the patient might try to avoid or delay by staying in the hospital.

#### *3.5. A Multi-Disciplinary Approach*

Cases with possible legal implications should involve a multidisciplinary approach to minimize risk and improve quality of assessment and management. Obtaining health records from other medical facilities, reviewing prior medical records, and obtaining collateral information from family members can yield vital sources of information in such cases. Ruling out possible medical issues or lies, such as was done in the Case 1 example above, can provide useful pieces of information in support of malingering. Medical providers may need to involve the ethics committee of the hospital, or consult with the legal department if they are unsure about addressing the legal aspects in these cases, such as in the context of duty to warn, and possible implications of discharging such a patient from the emergency room.

#### *3.6. Duty to Protect*

In the landmark ruling of Tarasoff v. The Regents of University of California [7], the court ruled that therapists need to take reasonable actions to protect potential victims of possible harm from their dangerous patients. When a patient makes a verbal threat against an identifiable victim, and the provider assesses such threat to be credible, the provider is directed to warn potential victims, inform the authorities, and/or take other necessary action to protect the life of potential victims [10]. Different states in the U.S. have adopted different standards in this area. While some states recommend a duty to warn potential victims, other states recommend a duty to take all necessary steps in addition to warning potential victims, to save lives. Some U.S. states mandate while others merely permit a breach of patient–provider confidentiality to carry out the established duty to warn/protect. While duty to warn is an accepted exception to confidentiality in most countries, only recently has it gained a legal precedent or background in other developed countries. [11]

#### **4. Conclusions**

We summarize the recommended steps for the evaluation and management of feigned homicidality in Table 2.

With the use of two case examples, we highlighted the assessment and management of feigned homicidality with an emphasis on the risk of verbal threat, assessment of the seriousness of the risk, differentiation from pseudologia fantastica, understanding duty to protect, and using a multidisciplinary approach.

We propose the addition of the assessment of malingering to the risk assessment for homicidality, especially in cases where there are enough reasons to suspect it. For example, a thorough screening for inconsistencies in the narration and presentation as well as potential external incentives for feigning homicidal symptoms may be included while using Borum and Reddy factors (expanding the acronym to ACTION). Other scales may be developed to include this dimension of homicidality.

**Table 2.** Steps recommended towards the evaluation and management of feigned homicidality.

**Author Contributions:** A.R.F. conceptualized and designed the study. All authors are psychiatrists who collectively conducted the clinical interviews, wrote the manuscript, and contributed to editing the paper. All authors revised and reached an agreement on the final version of the work. All authors have read and agreed to the published version of the manuscript.

**Funding:** No funding was obtained for this project.

**Institutional Review Board Statement:** As a policy, the institution's IRB does not review articles involving a case report or case series with two cases.

**Informed Consent Statement:** Written informed consent for publication was obtained from participating patients.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


**Emerging and Disruptive Next-Generation Technologies for POC: Sensors, Chemistry and Microfluidics for Diagnostics**

Editors

**Maria Serena Chiriac `o Elisabetta Primiceri Francesco Ferrara**

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*Editors* Maria Serena Chiriaco` Institute of Nanotechnology of CNR (CNR NANOTEC) Consiglio Nazionale delle Ricerche (CNR) Lecce Italy

Elisabetta Primiceri Institute of Nanotechnology of CNR (CNR NANOTEC) Consiglio Nazionale delle Ricerche Lecce Italy

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