E2- Ectoparasitic and Arthropod Flashcards
What is burrowing mite that is the most serious?
Sarcoptes scabiei
What ectoparasite causes scabies, crusted scabies, mange, and seven year itch?
Sarcoptes scabiei
What is the biology of a famale Sarcoptes scabiei?
- Fertilized on the skin surface
- Burrows into the epidermis
- Completes life cycle in 5 weeks and dies in the burrow
What is the biology of a male Sarcoptes scabiei?
- Remains on the skin surface or produces a shallow burrow
What is the life cycle of a Sarcoptes scabiei?
Eggs are laid under the skin
Larva emerges from the egg after 4 days
Adult mite develops 2 weeks after hatching
What is the main clinical manifestation of Scabies?
Pruritus (worse at night)
What causes the majority of clinical issues in a Sarcoptes scabiei infection?
Burrowing
What form of scabies has an incubation period of ~1 month, is observed readily in HIV patients, and has lesions that are teeming with mites?
Crusted (Norwegian) Scabies
What is similar to Crusted (Norwegian) Scabies, but lesions may be blood-filled?
Pediatric scabies
How is scabies usually transmitted?
Direct person contact (crowded living conditions)
In adults, likely and STI
May be zoonotic
How is scabies identified?
Apply mineral oil, scrape lesion and visualize microscopically
What is the causative agent of pubic lice “Crabs?”
Phthirus pubis
How are pubic lice transmitted?
Sexual contact or contaminated bedding
What is a causative agent of typhus?
Pediculus humanus
How long is the egg-to-egg cycle for Pediculus humanus?
3 weeks
How do Pediculus humanus mainly cause irritation?
Bite irritation (blood sucking parasites)
What can years of infestation of Pediculus humanus cause?
Vegabond’s disease (darkened, thickened skin)
What is the causative agent of human fleas?
Pulex irritans
What parasite is laterally compressed and has short spikes on the legs that allow attachment to the host?
Pulex irritans
What do Pulex irritans absolutely need to survive?
Blood