tick-borne disease tick-borne disease tick-borne diseases, which afflict humans and other animals, are caused by infectious agents transmitted by tick bites. they are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa. the economic impact of tick-borne diseases is considered to be substantial in humans, and tick-borne diseases are estimated to affect ~80 % of cattle worldwide. tick-borne diseasespecialtyinfectious disease as of 2020 18 tick-borne pathogens have been identified in the united states according to the centers for disease control and at least 27 are known globally. new tick-borne diseases have been discovered in the 21st century, due in part to the use of molecular assays and next-generation sequencing. the occurrence of ticks and tick-borne illnesses in humans is increasing. tick populations are spreading into new areas, in part due to climate change. tick populations are also affected by changes in the populations of their hosts (e.g. deer, cattle, mice, lizards) and those hosts' predators (e.g. foxes). diversity and availability of hosts and predators can be affected by deforestation and habitat fragmentation. because individual ticks can harbor more than one disease-causing agent, patients can be infected with more than one pathogen at the same time, compounding the difficulty in diagnosis and treatment. as the incidence of tick-borne illnesses increases and the geographic areas in which they are found expand, health workers increasingly must be able to distinguish the diverse, and often overlapping, clinical presentations of these diseases. prevention exposure a tick crawling on a human head in a wooded area near leroy, michigan. ticks tend to be more active during warmer months, though this varies by geographic region and climate. areas with woods, bushes, high grass, or leaf litter are likely to have more ticks. those bitten commonly experience symptoms such as body aches, fever, fatigue, joint pain, or rashes. people can limit their exposure to tick bites by wearing light-colored clothing (including pants and long sleeves), using insect repellent with 20%–30% n,n-diethyl-3-methylbenzamide (deet), tucking their pants legs into their socks, checking for ticks frequently, and washing and drying their clothing in a hot dryer. according to the world health organization, tick-to-animal transmission is difficult to prevent because animals do not show visible symptoms; the only effective prevention relies on killing ticks on the livestock production facility. tick removal ticks should be removed as soon as safely possible once discovered. they can be removed either by grasping tweezers as close to the mouth as possible and pulling without rotation; some companies market grooved tools that rotate the hypostome to facilitate removal. chemical methods to make the tick self-detach, or trying to pull the tick out with one’s fingers, are not efficient methods. diagnosis in general, specific laboratory tests are not available for rapid diagnosis of tick-borne diseases. due to their seriousness, antibiotic treatment is often justified based on clinical presentation alone. assessing risk for a person or pet to acquire a tick-borne disease requires that the individual gets bitten by a tick and that the tick feeds for a sufficient period of time. the feeding time required to transmit pathogens differs for different ticks and different pathogens. transmission of the bacterium that causes lyme disease is well understood to require a substantial feeding period. in general, soft ticks (argasidae) transmit pathogens within minutes of attachment because they feed more frequently, whereas hard ticks (ixodidae) take hours or days, but the latter are more common and harder to remove. for an individual to acquire infection, the feeding tick must also be infected. not all ticks are infected. in most places in the us, 30-50% of deer ticks will be infected with borrelia burgdorferi (the agent of lyme disease). other pathogens are much more rare. ticks can be tested for infection using a highly specific and sensitive qpcr procedure. several commercial labs provide this service to individuals for a fee. the laboratory of medical zoology (lmz), a nonprofit lab at the university of massachusetts, provides a comprehensive tickreport for a variety of human pathogens and makes the data available to the public. those wishing to know the incidence of tick-borne diseases in their town or state can search the lmz surveillance database. examples major tick-borne diseases include: bacterial lyme disease or borreliosis organism: borrelia burgdorferi sensu lato (bacterium) vector: at least 15 species of ticks in the genus ixodes, including deer tick (ixodes scapularis (=i. dammini), i. pacificus, i. ricinus (europe), i. persulcatus (asia)) endemic to: the americas and eurasia symptoms: fever, arthritis, neuroborreliosis, erythema migrans, cranial nerve palsy, carditis, fatigue, and influenza-like illness treatment: antibiotics - amoxicillin in pregnant adults and children), (doxycycline in other adults relapsing fever (tick-borne relapsing fever, different from lyme disease due to different borrelia species and ticks) organisms: borrelia species such as b. hermsii, b. parkeri, b. duttoni, b. miyamotoi vector: ornithodoros species regions : primarily in africa, spain, saudi arabia, asia in and certain areas of canada and the western united states symptoms: relapsing fever typically presents as recurring high fevers, flu-like symptoms, headaches, and muscular pain, with less common symptoms including rigors, joint pain, altered mentation, cough, sore throat, painful urination, and rash treatment: antibiotics are the treatment for relapsing fever, with doxycycline, tetracycline, or erythromycin being the treatment of choice. typhus several diseases caused by rickettsia bacteria (below) rocky mountain spotted fever organism: rickettsia rickettsii vector: wood tick (dermacentor variabilis), d. andersoni region (us): east, southwest vector: amblyomma cajennense region (brazil): são paulo, rio de janeiro, minas gerais. symptoms:fever, headache, altered mental status, myalgia, and rash treatment: antibiotic therapy, typically consisting of doxycycline or tetracycline helvetica spotted fever organism: rickettsia helvetica region(r. helvetica): confirmed common in ticks in sweden, switzerland, france, and laos vector/region(s)#1: ixodes ricinus is the main european vector. symptoms: most often small red spots, other symptoms are fever, muscle pain, headache and respiratory problems treatment: broad-spectrum antibiotic therapy is needed, phenoxymethylpenicillin likely is sufficient. human granulocytic anaplasmosis (formerly human granulocytic ehrlichiosis or hge) organism: anaplasma phagocytophilum (formerly ehrlichia phagocytophilum or ehrlichia equi) vector: lone star tick (amblyomma americanum), i. scapularis region (us): south atlantic, south-central bartonella: bartonella transmission rates to humans via tick bite are not well established but bartonella is common in ticks. for example: 4.76% of 2100 ticks tested in a study in germany tularemia organism: francisella tularensis, a. americanum vector: d. variabilis, d. andersoni region (us): southeast, south-central, west, widespread viral tick-borne meningoencephalitis organism: tbev (fsme) virus, a flavivirus from family flaviviridae vector: deer tick (ixodes scapularis), ixodes ricinus (europe), ixodes persulcatus (russia + asia)) endemic to: europe and northern asia powassan virus/deer tick virus organism: powassan virus (powv), a flavivirus from family flaviviridae. lineage 2 powv is also known as deer tick virus (dtv) vector: ixodes cookei, ix. scapularis, ix. marxi, ix. spinipalpusm, dermacentor andersoni, and d. variabilis endemic to: north america and eastern russia colorado tick fever organism: colorado tick fever virus (ctf), a coltivirus from the reoviridae vector: dermacentor andersoni region: us (west) crimean-congo hemorrhagic fever organism: cchf virus, a nairovirus, from the bunyaviridae vector: hyalomma marginatum, rhipicephalus bursa region: southern part of asia, northern africa, southern europe severe febrile illness organism: heartland virus, a phlebovirus, from the bunyaviridae vector: lone star tick (amblyomma americanum) region: missouri and tennessee, united states severe febrile illness, headaches, coma in 1/3 patients organism: tentatively alongshan virus, jingmenvirus group in the flavivirus family vector: tick (likely ixodes persulcatus, ixodes ricinus), mosquitoes region: inner mongolia but potentially more widespread protozoan babesiosis organism: babesia microti, theileria equi vector: ixodes scapularis (deer tick), i. pacificus (western black-legged tick) region (us): northeast, west coast cytauxzoonosis organism: cytauxzoon felis vector: amblyomma americanum (lone star tick) region (us): south, southeast toxin tick paralysis cause: toxin vector (us): dermacentor andersoni (rocky mountain wood tick), d. variabilis (american dog tick or wood tick) region (us): d. andersoni: east, d. variabilis: east, west coast vector (australia): ixodes holocyclus (australian paralysis tick) region (australia): east allergies alpha-gal allergy - alpha-gal syndrome is likely caused by a hypersensitivity reaction to the alpha-gal (galactose-alpha-1,3-galactose) sugar molecule introduced by ticks while feeding on a human host. the immune reaction can leave people with an allergy to red meat and other mammalian derived products.