TAMU ENTO 210 - Final Exam Study Guide (19 pages)

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Final Exam Study Guide

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Final Exam Study Guide


A study tool for the material from lectures 17-24, and brief summaries of the required reading.

Study Guide
Texas A&M University
Ento 210 - Global Public Health Ent
Global Public Health Ent Documents
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ENTO 210 1st Edition Final Exam Study Guide Lectures 17 24 Lectures 17 Sandflies and Leishmaniasis Leishmania a genus of Trypanosomatidea like Chagas and Sleeping sickness considered a Neglected Tropical Disease NTD Sandfly is the vector 2nd most important protozoan medically and economically a few are almost entirely human very common 70 000 500 000 deaths annually Leishmania life cycle involves promastigotes and amastigotes fly bites human and injects promastigotes promastigotes change to amastigotes inside the macrophages of the human the amastigotes in the macrophages multiply and taken up in a blood meal by the sandfly they change to promastigotes in the midgut of the sandfly and migrate to the proboscis where they are injected into another human Leishmaniasis Transmission sandfly bites are the most common it can also pass mother to fetus and through blood transfusions Sandfly diptera psychodidae phlebotominae almost 1000 species about 70 carry human disease important genera Phlebotomus old world sand fly semiarid conditions seasonal cutaneous leishmaniasis visceral leishmaniasis and mucocutaneous leishmaniasis which is the rarest Lutzomyia new world sand fly forest conditions regularly present cutaneous leishmaniasis visceral leishmaniasis and mucocutaneous leishmaniasis females usually nocturnal feeders larvae not commonly found total life cycle is 30 60 days some are endophagic adults are weak flyers and usually stay close to home Cutaneous Leishmaniasis causes a pizza like lesion usually scars 90 of cases occur in the Middle East and some of South America most people get in childhood scars can cause social issues in some cultures abandonment etc at one point they would infect children in a place not very visible so they would get it over with and not risk persecution maintained in rodents hyraxes and dogs some systemic drugs work many are expensive Mucocutaneous Leishmaniasis Espundia 90 in South America mostly caused by L brasiliensis usually starts with lesion and then chronic ulcers can affect nose cartilage need systemic drugs and surgery Visceral Leishmaniasis black fever mostly in Asia Brazil and Sudan can affect bone marrow liver and spleen fatal if left untreated often victim to other diseases old world vectors L donovani L infantum new world vectors L chagasi lesion swelling fever infections maintained in dogs need systemic drugs Control IRS treated bed nets control the reservoirs War has had great affect in the sudan civil war largely because of the malnourished people risk for American soldiers Lecture 18 Ticks Ticks Cheliceriforms Arachnida Acari large have a toothed hypostome 2 major families Argasidae soft ticks have 8 legs Ixodidae hard ticks have scutum and 8 legs it s important to note that the larvae have 6 legs Argasidae over 180 species females blood feed more than males lay several eggs after each meal found in burrows and nests medical issues tick paralysis more so in hard ticks neurotoxin can cause death tick born relapsing fever Borellia found everywhere but Australia and New Zealand can last 2 9 days and recurs regularly can live up to 7 years able to withstand long term starvation Ixodidae over 700 species temperate climates stay on host for up to 4 weeks then drops and hides female lays thousands of eggs and dies larvae and nymph prefer small animals males usually mate with female on host Questing ticks wait for CO2 increase as sign of host review the differences between soft and hard ticks Lyme Disease newly emergent first identified in 1970s most widespread vector borne disease Borellia burgdorferi deers are not a reservoir over 20000 US cases annually Ixodes scapularis is the main vector on the east coast frequently on deer why deer associated with lyme disease cases have to be reported to health officials Stage 1 Erythema chronicum migrans bullseye rash 80 frequency can also have symptoms that resemble flue Stage 2 pathogen spreads through blood stream rash can be all over body pain in muscles and joints affects the heart dizziness Stage 3 if untreated can have severe symptoms chronic neurological symptoms are possible like encephalomyelitis lyme arthritis It s important to note there is no correlation with poverty level treatment antibiotics must be used early it s important to remove ticks early reduce the primary hosts treat deer with tick killing substances Lecture 19 Lice Phthiraptera Mallophaga chewing lice about 3000 species feed on hair Anoplura sucking lice feed on blood higher fecundity reproductive rate about 500 species high host speciation most affect rodents 3 species affect humans body louse head louse pubic louse Human lice both sexes feed 3 6 times a day lay several eggs daily prefer temperate regions survive 2 4 weeks Body louse pediculosis infestation with lice can have 100s at once common in areas with poor hygiene jails refugee camps etc Vagabond s disease long term exposure skin can change texture and color can also affect behavior Head louse nits cement onto hair little medical significance more common among children Pubic Lice aka crabs found in course body hair spread through sexual contact most frequently no serious medical significance Control hygiene makes a huge difference shave hair treat with insecticides Diseases Trench fever Bartonella quintana non fatal transmitted through lice feces infection by inhalation big during World war 1 5 day relapsing fever headache pain can cause heart failure rare Louse borne relapsing fever Borellia recurrentis bacteria enters people through cuts scrapes Central and East Africa most in Sudan and Ethiopia high fever cough weight loss up to 40 fatality if untreated Epidemic Typhus Rickettsia prowazeki obligate intracellular parasite kills lice bacteria enter humans through skin cuts and inhalation fever rash 50 frequency pain heart failure up to 40 fatality children don t normally die humans are reservoir common in wars camps jails Anne frank was a victim Control hygiene helps a lot insecticides treat clothes and beds antibiotics help vaccine no longer used in US potential for biological weapon Lecture 20 Fleas Siphonaptera about 95 of species feed on mammals have specialized hind legs for jumping evolved from winged insects wingless now life cycle varies from about a week to almost a year both genders blood feed most don t remain on host Ctenocephalides felis does Results of having fleas Nuisance mostly cat flea bite area varies by time can cause allergic reactions often also

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