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Arthropoda Arachnida
Acari
Trombiculid (chigger) mites
Demodex folliculorum, D. brevis
Prevalence: 1/3 of children 1/2 of adults 2/3 elderly
SarcopEc/PsoropEc mange
• Sarcoptes scabiei: humans, related forms in other animals.
Adult inseminated female burrows under skinfeeding on digested Essues, periodically (2 – 3 eggs per day) laying an egg. AIer 3-‐4 d eggs harch into larvae which go to surface and repebetrate form a moulEng chamber.
Acari, ParasiEformes
• Dermanyssus gallinae • Ixodida: the Ecks
Dermanyssus gallinae, red chicken mite.
Micropredator. Live in cracks/crevices during the day feeding on the host at night when it is resEng. Pathology: Itching, scratching secondary infecEon. Repeated feeding can transmit disease
Argasidae and Ixodidae
• SoI Ecks: e.g Argas persicus. Micropredator
• Capitulum and mouthparts not visible from above.
• Feed repeatedly on different host individuals: good . potenEal vector.
Life cycle diversity in Ixodid Ecks
Eggs in external environment hatch. Larvae search for host, feed; moult to nymph, feed; moult to adult feed. One host, two host and three host cycles exist depending on the Eck.
Dermacentor andersoni • Larva and nymphs feed on rodents and small mammals; adults feed on deer, moose, elk, or occasionally humans
Disease: Eck paralysis (BC) Rocky Mountain spoWed fever (SW USA)
Amblyomma americanum
Large mammals including man. Vector: Tularemia, Rocky mountain spoWed fever
Rhipicephalus sanguineus
• Brown dog Eck. Cosmopolitan with man.
• Feeds on dogs as larva, nymph and adult
• Vector potenEal very high: babesiois, ehrlichiosis
Boophilus microplus
• A one host Eck. Infects caWle and other Bovidae throughout tropics/subtropics.
• Babesia (causes a malaria like disease) transmiWed by the Eck: Babesia parasite infects the Eck eggs.
Ixodes scapularis
Lyme disease: Borrelia burgdorferi
• Endemic in wild rodent populaEons • Tick enable transmission to humans especially in eastern North America
• Ixodes pacificus can serve as vector in west.