**3.17 X-linked severe combined immunodeficiency (SCID-X1)**

X-linked severe combined immunodeficiency (SCID-X1) is caused by the mutations of interleukin-2 receptor subunit gamma (IL2RG) gene. Patients with the disease lack of T cells and natural killer cells, their B cells are functionally impaired; therefore, they are extremely vulnerable to infections (Aiuti & Roncarolo, 2009; Cavazzana-Calvo et al., 2000; Gaspar et al., 2004; Hacein-Bey-Abina et al., 2002, 2010).


**10. Summary**

Poor long-term patencies of saphenous vein grafts coupled with the greater long term patency results of the LIMA as the gold standard conduit for CABG has prompted sur‐ geons to seek out additional arterial conduits [1,2]. Achieving total arterial revasculariza‐ tion of the myocardium would then be a natural progression for the procedure.

Since it is anatomically identical to the LIMA, the RIMA would be the next logical choice in arterial conduits, yet is rarely used in CABG operations due to the perceived technical difficulty of harvest and increased operating times, a higher risk of developing SWIs, and previous lack of long-term studies of clinical outcomes [7,8]. However, several studies have demonstrated significantly increased long-term survival rates for patients receiving BIMA grafting compared to SIMA grafting [9-12]. BIMA patients also have significantly improved cardiac event-free survival than SIMA patients [4, 6, 9]. Patency rates for RI‐ MA grafts have also been shown to be similar to those of the LIMA, even when consid‐ ering the sites of distal anastomoses and the proximal anastomosing techniques [16, 17, 18, 19, 20]. Further studies are needed to determine if there is any significant effect on operative length in BIMA grafting versus conventional CABG.

The incidence of SWI has been a significant concern for surgeons, especially among high-risk patients such as the morbidly obese, insulin-dependent diabetics, and those with COPD. BIMA harvesting is generally avoided in these patients [7, 8], however studies have shown that BIMA harvesting in general does not significantly affect the incidence of SWIs [12, 23]. The risk of SWI can be even further reduced with the use of skeletonized BIMA harvesting rather than pedicled harvesting [22, 23].

Studies have shown that the radial artery is also a good choice for an arterial conduit after the LIMA. Studies examining clinical outcomes and patency rates of the radial artery have been mixed, with some studies showing better short-term patency rates than saphenous vein grafts [25-28], while other studies have shown that radial artery outcomes are at least similar to those for the RIMA and saphenous vein [11, 32, 33].

While not all studies have been favorable with regards to BIMA and radial artery use [11, 15, 32, 33], studies generally find patency rates and clinical outcomes of these two arterial conduits are at least as good as the currently accepted standards of care, which should give surgeons flexibility in their choice of conduits, ultimately leading to total arterial revascularization.

Studies in general have provided favorable results for TAR, with TAR at least being similar in outcomes to conventional CABG [35]. Several studies have demonstrated that TAR, and the use of arterial conduits in general, provides significantly better late survival (especially in patients with three vessel coronary disease), cardiac event-free survival, and improved healthrelated quality of life when compared to conventional CABG [11, 21, 36].


**2. Methodology and System Modeling**

Figure 1 shows the proposed microgrid system infrastructure; which consist of the WT, PV, PHES, and AC loads connected through an AC bus. The energy management system is also included as the control center for the microgrid. The mathematical models that describe the behavior of each system component and the energy management strategies deployed in this study are discussed below.

**Figure 1.** Proposed system model.


3. The 2014 West African Ebola outbreak

believed to be transmitted by bats being the primary reservoir mostly through body fluid or contact to humans and other primates. The virus can penetrate mucosal membrane to infect various cells in the body including macrophages, monocytes, dendritic cells, etc. and spread into the circulatory and lymphatic systems damaging blood vessels leading to haemorrhage. Though no approved standard treatment is available for the disease, it has been managed with certain antiretrovirals and supportive treatments such as rehydrating solutions for maintaining fluid and electrolyte balance as well as treatments against secondary infections. Thus, the availability of a standard approved drug is one of main concern in recent time following the 2014 fatal outbreak. More so, since this disease is sporadic and usually emerges as an outbreak, effective control is usually difficult as diagnosing viraemia is usually challenging. Also, no existing vaccine is available against the disease. Following the introduction of experimental drugs and vaccines during the 2014 West-Africa Ebola outbreak which contributed to its control [3], it has been of interest to know the progress so far and efforts that are been laid to ensure that these drugs and vaccines are licensed in future. Hence, this chapter will focus on the progress towards the provision of diagnostic tools, and availability of specific treatments and vaccines. However, an understanding of the aetiology and pathogenesis of Ebola virus disease is necessary so as to expose possible drug targets as well as various vaccine candidates

This viral disease emerged around 1976 with the first outbreak in the northern part of DRC, formerly known as Zaire which affected about 318 individuals with a mortality rate of 88% [1]. Almost at the same period and year, another outbreak emerged in southern Sudan with 284 cases killing about 150 individuals (53%) [4]. In 1976, a case of the infection of the Sudan virus was identified in England but there was no casualty [5]. The following year in 1977, a case was reported in DRC which the individual died. By 1979, there was reoccurrence of an outbreak in Southern Sudan which affected 34 individual with a 65% mortality rate. The disease was absent for about 2 decades before re-emerging in Gabon and Ivory Coast in 1994, with a mortality rate of 60% in Gabon [6]. The disease reoccurred in Gabon in 1996 and 1997 [6], and again in DRC in 1995 [7]. In 2000, an outbreak was reported in Uganda with over 80% mortality while the following year, another outbreak was reported in Gabon with 53% and 82% mortality rate respectively [8]. Since then, there has been reoccurrence of outbreaks in DRC between 2001 and 2008 [9] and in Uganda between 2007 and 2012 [10]. In 2012, there was another outbreak in DRC with a fatality rate of about 40% [11]. In 2014, the largest outbreak was recorded in DRC [12] and West Africa [13] that spanned across various countries including United State, Spain, Mali, Senegal and Nigeria [14].

It should also be noted that some non-human primate infections have also occurred. The first to be observed was in the United States between 1989 and 1990 [15] followed by another outbreak in Italy in 1992 which were related to the importation of monkeys from the Philippines [16]. In 2008, cases of respiratory and porcine reproductive syndrome in sows and piglets caused by the Ebola virus were observed in China and Philippines with high mortality. Animal farmer workers who were in contact with the virus became infected but the infection was

for a better management of the disease.

130 Current Topics in Tropical Emerging Diseases and Travel Medicine

2. The origin and epidemiology of Ebola virus disease

asymptomatic and no casualties were recorded [17].

The first trace of the infection was in Guinea in December 2013 which subsequently spread to Liberia and Sierra Leone. In 2014, the world recorded the largest Ebola virus outbreak in West Africa particularly in Sierra Leone, Guinea, and Liberia, with over 7178 infected cases 3338 deaths amounting to a mortality rate of 51% as of 1st October, 2014 [18]. Also, the disease spread to other countries including Nigeria and USA. [18]. In August 2014, the epidemic was declared by the World Health Organization (WHO) as a public health emergency of international concern [19]. By September 2014, the fatality rate of infected individuals was about 70.8% in Liberia, Guinea, and Sierra Leone. About 20 cases were report in Nigeria which originated from a traveller from Liberia in July 2014 with a fatality rate of 45.5%. As of 23rd October, 2014, about 450 health care personnel were known to be infected with Ebola virus of which 244 died [20]. In October 2014, two imported cases with one death, as well as two locally acquired cases from health care workers were identified in the United States. By November 2014, a cumulative total of 20,000 Ebola cases were reported in the West Africa outbreak including 5740 cases from Guinea, 9890 from Liberia and 5000 from Sierra Leone [20] killing over 11,300 individuals within the course of 2 years.


**Abstract**

Monitoring is essential to evaluate the effects of wetland restoration projects. Assessments were carried-out after 6 years of restoration efforts on a wetland located in two agro-ecological zones (AEZ): the Mountains agro-ecological zone– *Khalongla-lithunya* (KHL) and the Foot Hills–*Ha-Matela* (HM). The former was under conservation and the latter non-conserved. Mini-pits were dug along transects for soil sampling. Runoff water was collected from installed piezometers into pre-rinsed plastic bottles with de-ionized water once a month for between 3 and 6 months. Soil and water samples were analyzed in the laboratory for Ca, Mg, K, Na, total nitrogen, and phosphorus, and soil samples were further analyzed for Cu, Fe, Zn, and Mn and vegetation isotopic N15. Water quality, soil organic matter (SOM), carbon pools, base cations, ratios (silt:clay & SOM:silt clay), texture, and N-15 isotopes were chosen as indicators. Results showed that base cations were significantly (p < 0.05) higher in the groundwater and soils of KHL wetlands compared with those from the HM. The soils of the KHL wetlands have higher (p < 0.05) clay, silt contents, SOM, and silt clay ratios compared with the HM. Furthermore, results of the N15 isotopes were between 2.52 and 2.93% (KHL) compared with 2.00 and 6.18% (HM). Similarly, the results of the δ13C showed significant negative values at KHL (28.13–28%) compared with HM (11.77–12.72%). The study concludes that after five years of rehabilitating the KHL wetlands, the soil indicators showed that restoration efforts are positive compared with the HM wetlands that are non-conserved.

**Keywords:** catchments, grazing, N15 isotopes, Lesotho, wetland, nutrient dynamics, restoration

## **1. Introduction**

The Kingdom of Lesotho covers a land area of 30,355 sq. km and is situated within the Southern African plateau at an elevation of between 1500 m and 3482 m above sea level. It has four agro-ecological zones (AEZ) based on climate and elevation (**Table 1**). All the AEZ's are replete with wetlands. Wetlands locally called *mekhoabo* (*plural*) and *mokhoabo* (singular) occur as extensive bogs and spongelands especially in the Mountains AEZ, though may be small in extent, collectively, they could cover thousands of hectares.

In Lesotho, over the years, more emphasis of agriculture (cropping and grazing) has been placed on upland soils, but due to increasing degradation of uplands coupled with lack of vegetation for grazing, attention is now shifting to wetland soils as it now constitutes an important component of rural livelihoods for the *Basothos*. Wetlands are defined as "areas that have free water at (or on the surface) for at least the major part of the growing season" [1]. In Lesotho, land ownership is vested in the paramount chiefs, hence, no land is privately owned. These chiefs thus grant the right to cultivate lands to individuals or groups, but all citizens are free to graze livestock on all lands [2].

Wetlands are critical to maintaining and improving the quality of lives in sub-Saharan Africa (SSA) by improving livelihoods of rural populations and reducing poverty especially in the summer seasons and in times of droughts [3]. In Lesotho, wetlands are also known to support grazing, forestry and cropping activities, hence can be said to be ecologically, economically and socially important [3]. According to Grenfell et al. [4], wetlands in the Southern African region was classified into seven main groups: marine, estuarine/lagoon, endorheic, riverine, lacustrine, palustrine and man-made wetlands. However, the wetlands investigated were of lacustrine and riverine systems. Lacustrine wetlands include lakes, lagoons, and dams; riverine wetlands include rivers, streams and channels. Palustrine, lacustrine and riverine wetland systems are found in Lesotho with the palustrine system being the most dominant. The palustrine system in Lesotho comprises of mires (bogs and ferns) in the highlands region, while, lacustrine system comprises of artificial impoundments for water supply and riverine system found along streams are generally small and localized [5, 6].

Agricultural activities (such as grazing and cropping) are thought to be the major contributors to non-point wetland pollution in the highlands and foothills respectively while industrial effluents and domestic waste disposal are thought to contribute significantly to wetlands' pollution in urbanized and industrialized Lowlands AEZ. In Lesotho, wetlands are important for livestock grazing and the problems related to wetlands management, in particular, soil erosion, are related to overgrazing [3]. Land degradation in upland areas is thought to also be a major contributor to the conversion of wetlands into crop lands as the upland areas are degraded beyond use [7]. There are sparse data on the chemical characteristics of wetlands in *Khalong-la-Lithunya* (KHL) and *Ha-Matela* (HM) catchments which are located in

#### **Table 1.** *Agro-ecological characteristics of Lesotho.*

### *Wetland Health in Two Agro-Ecological Zones of Lesotho: Soil Physico-Chemical Properties… DOI: http://dx.doi.org/10.5772/intechopen.101836*

two different AEZ of Lesotho. The former has been under conservation practices for over 6 years. A restoration project was introduced in some wetlands in Lesotho 2006 to restore some degraded wetlands back to their original status in view of their importance in the country. The latter wetland (HM) is still being used for livestock grazing, watering, cropping and gathering of biodiversity. In 2006, the country was awarded a grant by the Millennium Challenge Corporation (MCC), USA to plan restoration and conservation activity in selected wetlands in Lesotho which will address the widespread overgrazing and degradation of wetlands which are prevalent throughout the highlands of Lesotho. These wetlands are an important ecological and economic resources as they naturally regulate flow in the Senqu/Orange River Basin and provides livestock pasture, medicinal plants, thatch, and other rural livelihood benefits. Several reports abound on wetland restoration activities (Gray et al., 2002; [8–12]). These authors reported that wetland restoration focuses on restoring three key components—hydrology, biology, and soil—of wetlands. It is required that detailed investigation of these components is examined and how they change during the ecosystem restoration process. Some of the properties that may be observed include changes in hydro-periods and water chemistry [9, 13–15]; changes in the wildlife habitats [12, 16].

The effects of wetland restoration are commonly evaluated by analyzing changes in the hydrology, biological components and the physical and chemical properties of soil [9, 10, 17]. Also of importance is the changes in the vegetation composition and structure, in terms of percent cover, biomass, plant diversity associated with re-establishment of species [18–20] as well as the changes in the soil microbial communities, and functioning [21, 22] and isotopes.

Stable nitrogen isotope measurements may be used to examine the nitrogen cycle within landscapes [23, 24]. Biological discrimination between the two stable isotopes 14N and 15N often leads to natural isotopic fractionation [23, 24]. It is well established that denitrification results in isotopic changes in the nitrate (NO3 ) pool, as bacteria preferentially reduce 14NO3 over 15NO3 , leaving an enriched pool of 15NO3 [23, 24]. The isotopic signature has been used to identify regions of significant denitrification in groundwater aquifers, streams and riparian buffer zones [23, 24]. Partitioning carbon contributions from different species to the soil carbon is challenging. Among the numerous methods, the carbon isotopic technique based on the difference in stable carbon isotope composition (δ13C) ratios between older soil carbon and inputs of new carbon appears promising [25, 26]. This technique studies soil carbon dynamics over a few years or several 100 years, and the results can help to understand the consequences of human induced land use change [27, 28].

This study focused on changes in soil characteristics, especially selected soil physico-chemical characteristics and hydrochemistry of the run-off water. The hypothesis was that conservation/restoration of wetlands coupled with the introduction of freshwater/rainwater would alter the soil characteristics resulting in increased accumulation of SOC, total N (TN), base cations (Ca, Mg, Na & K), Cpool as well as increased clay and silt contents, increase in silt:clay and soil organic matter:siltclay ratios (SSCR). The aim of the management effort was to reduce the wetland degradation, which is the primary threat to the wetlands in Lesotho, and provide conducive habitats for wetlands vegetation and faunal species. The specific objectives of the current study were to evaluate whether there were differences in the soil (i) physicochemical properties and (ii) hydrochemistry of a wetlands under conservation and the one that is not conserved to assess the effect of restoration after 5 years; the results are intended to support the ongoing restoration efforts in selected wetlands in Lesotho and (iii) to estimate the δ C and δ N in the plant samples of the conserved and non-conserved wetlands.