Introduction to Parasitology and Arthropods Flashcards
Definitive host
Where adult or sexually reproductive stages live
Intermediate host
Where the larval stages live
Vector
Organisms that transmit disease from host to host
Reservoir host
Animals that maintain a human infection
Insect characteristics
3 pairs of legs, head, thorax abdomen, various types of mouthparts, may have wings
Where multiplication of infectious agent usually occurs
Within the vector
phthirus pubis
crab louse, large claws on back 2 legs
Pediculus humanus capitis
Hair louse, intense pruritis depending on number and host sensitivity
Lice treatment
- Medicated shampoo plus nit picking
- Repeat one week later
- Treatment of clothing and furniture with heat/insecticides/seal off for 2 weeks
- Treat family (highly contagious)
Disease transmission of lice
Body louse only - epidemic typhus, trench fever and relapsing fever
Pediciculus humanus humanus
nit on clothing
Cimex lectularius characteristics
Bed bug
No wings, covered with hairs. Night feeders. Can live a year without feeding. No disease transmission.
Triatomid characteristics
Assassin bug or kissing bug, have wings, bite on face, lips and outer angle of eye. Transmit trypanosoma cruzi (chagas)
Myiasis
Fly larval infection due to invasion, treat with petroleum jelly to get fly larvae to exit, or surgical intervention
Mosquito transmission of disease?
Via the females only, feed on blood and transmit malaria, filarial worms, yellow fever, dengue, viral encephalitis.
Tick and mite characteristics
No external segmentation, four pairs of legs, mites are smaller and have no teeth on hypostome
Hard tick characteristics and vector for?
Dorsal scutum, not host-specific. Long feeding period. Can cause tick paralysis especially if bite is along spinal column. Vector for Rocky Mountain Spotted Fever, babesiosis, Lyme, ehrlichia, tularemia.
Soft tick characteristics
No scutum, bite is short duration, transmit endemic relapsing fever
Sarcoptes scabiei
Mite, seen beneath breasts, belly folds of babies and interdigital webs. Adults lay eggs in tunnels, hatched larvae migrate to surface of skin. Severe dermatitis. Disease: scabies or mange.
Secondary bacterial infection is a problem.
Demodex folliculorum
50-100 percent of adults infected. Found in hair follicles, sebaceous glands of face. Rarely requires treatment.
House dust mites
Feed on organic debris, cause allergic responses including asthma.
Centipedes vs Millipedes
Centipedes cause painful wound from venomous claws, one appendage/segment.
Millipedes have no claws and have two appendages/segment.
Scorpions
Found in arid regions including SW US. Neurotoxic and hemotoxic venom. 8 legs. Specific anti-venom available.
Black widow spider
Latrodectus mactans. Red hour glass on ventral aspect of abdomen. Neurotoxic venom. Pain and swelling, severe burning and aching sensation, leads to cramps with board-like rigidity of abdomen.
