ENTO 208 1st EditionExam # 3 Study Guide Lectures: 18 - 21(Also contains the online lectures)Lecture Main PointsPractice questionsLecture 18Ticks (Intro)I. Phylogeny a. Ixodida (order/suborder) i. Families: Ixodidae (hard ticks), Argasidae (soft ticks), Nuttalliellidae (African ticks)II. Importancea. All ticks are parasitesb. Greatest variety of disease transimittance among arthropodsc. Second most important animal/human health vectorIII. Anatomy (main parts for Tick ID)a. Male vs. Female for soft ticksi. Scutum: covers upper half of dorsal side for females, covers entire dorsal side formalesIV. Generaa. Ixodesi. Lyme disease vectorii. Largest tick genus speciesb. Dermacentori. Short palps Scutum ornamentedc. Amblyommai. Long palpsii. Scutum ornamented (lone star tick has a white dot on dorsal side)d. Otobiusi. Single host tickii. Adults leave host, don't feed, just mate and lay eggsiii. Not known to transmit disease (there are soft ticks known to do so)V. Tick life stagesa. Larvae – 6 legsb. Nymph – 8 legs, highest risk of human infection (host seek in late spring, summer)c. Adult -host seek in fall as well*Tick must be attatched for 48 hours to transmit agentLecture 19Tick borne diseases Tick behaviorHost seeking - passive (ambush), active (hunters)Questing behavior (ixodes scapularis)Hunting (lone star)Tick EcologyVarying degrees of host specificityHost utilization depends on availabilityNidicolous ticks: live in nests or other shelters used by the hostsNon-nidicolus: Dispersed throughout landscape attacking passing hostsDirect impactDermatitis/AlopeciaExsanguinationTick toxicosisTick paralysisAllergies Lyme diseaseAgent: Borrelia burgdorferi (spirochete)#1 reported vector borne disease in USVectored by: Black legged tick (ixodes scapularis), carried by white footed mouseIn humans: early stage (bulls-eye rash, flu-like symptoms)Late stage (several months later, cardiac, neurologic, arthritic abnormalities) Rocky Mountain spotted feverAgent: rickettsia rickettsiiVectored by: Dermacentor variablisBabesiosisAgent: babesia spp protozoaVectored by (in US): Ixodes scapularisHuman babesiosis: Babesia microt, emerging disease, malaria-like symptomsCattle babesiosis: B. bovis or B. bigemina, affect the central nervous systemCattle tick fever, Cattle tick*most important tick of livestock in the world, has been confined to Mexico*short mouth partsLecture 20Tick-borne diseases (continued)- Equine Piroplasmosiso Agent: Thelieria equi & Babesia caballio Vectored by: Dermacentor variablilis, Amblyomma cajennense, Rhipicephalus micropluso Symptoms: fever, reduced aappetite, anemiao *chronic lifetime infection w/ T. equi; B. caballi is cleared by the immune systemo *King Ranch Texas out break - Relapsing Fevero Agent: Borrelia turnicatae (spirochete)o Hosts: humanso Vectored by: Argasidae- African Swine Fevero Agent: icosahedral DNA virus (Family: Iridoviridae)o Host: Domestic/feral pigs, european wild boar, and warthogso Vectored by: Ornithodors spp.- Ehrilichiosis (rickettsia)o Human type Agent: Ehrlichia chaffeensis and E. ewingii Vectored by: lonestar ticko Canine type Agent Ehrlichia canis Vectored by: Rhipicephalus sanguines- Anaplasmosis (granulocytic anaplasmosis)o Agent: anaplasma phagocytophilum (humans, dogs, cats, horses), A. marginale (cattle), A. centrale (cattle), A. ovis (sheep)o Vectored by: Ixodes spp., Tabinae (mechanical transmission), D. andersoni, D. occidentalis, D. variabilis Tick & Tick borne disease control:Personal protectionEnvironmental ReductionHabitat modificatoinHost RemovalRotational grazing (reduce population density per paddock)Acaricides: pesticides to kill ticks and mites(Pyrethroids is the safest and most effective)Passive treatment of wildlife Treatment of livestockHost Removal Lecture 21Kissing Bugs Order: Hemiptera, Suborder: Heteroptera, Family: Reduviidae, 13 genera in the western hemisphereAll stages are obligate hematophagous5 nymph/immature stages, winged adultsAttracted by CO2, heat, light (Houses have all of these)They are dark brown/black, with stripes, thin legs, a cone-nose, and thin rostrum (mouth part)Where?Can be found across the country, mainly the southern halfLocal hosts: sylvatic (opossums, rats, bats, anything really), peridomestic (dogs, chickens, rabbits), domestic (in houses, some have lost the ability to live outside) Chagas diseaseIn Texas: found in dogsLife cycle of agent: deposited on skin by bug's feces, rubbed into bite wound by host, enters body and travels to heartSterocorial transmission: some people think that the cases are fewer in the US because the bugs here wait to poop till they are off the host, not proven**Diagnosing Chagas disease: antibody detection, microscopic detection of parasite, culture, detection of parasite DNAOnline/Camtasia LecturesMitesTaxonomy: Subclass: Acari (ticks and mites)Superorders: Acactinotrichida & ActinotrichidaAbout 250 species are recognized as causing health-related problems Morphology:Ticks vs. MitesTicks MitesSize Larger, macroscopic Smaller, microscopicExoskeleton Leathery, harder to squish MembranousHypostome Contain teeth, obligate blood-feeders @ all stagesNo teethParasites? Always Sometimes, some live in the soil, some are only parasitic @ certain stages LifecyclePre-larval are (non-feeding)Larva have six legs (hematophagous, like ticks)Protonymph, Deutonymph (is non feeding and is a transportation stage), TritonymphAdultMite ProblemsDirect & Indirect>90% of humans have follicle mites (demodex mites)Can lead to: Skin irritation (possibly mange) Dermatitis Allergies (dust mites, allergic reactions) Transmission of pathogens Intermediate hosts for helminthes (ex: cestodes and a filarial nematode) Delusory acariosis (psychological condition – false belief that mites are present)Direct Problems:Dermatitis and Allergies Penetrate skin -> dermatitisInhaled -> respiratory tract infections, digestive system infectionsDust MitesFeed on fungi (found commonly in areas of high humidity)Large problem for health -> respiratory allergiesChiggersLarvae of the Trombiculidae family (mites)Only parasitic stage of mites, variety of hostsFeed on skin cells, do not burrow into skinEggs are laid in soil, larvae feed in soil for several days, drop off to moltNymphs and adults are free-livingSarcoptes scabiei Agent of mange (scabies)Female burrows into skin, male follows to mate, female continues to burrowIndirect Problems:Mite-borne diseaseTsutsugamushi disease