Micro: Parasites and Infestation Flashcards
Pathogenesis of the nematode that you catch in sandboxes or on the beach.
Ancylostoma braziliense: causes cutaneous larva migrans
-larvae penetrate the skin on feet but remains in the subcutaneous tissue until the eosinophilic response eliminates the infection.
Nematode contracted from drinking water containing an infected Cyclops microcrustacean.
Dracunculus medinensis
Treatment for D. medinensis skin infection.
Once the worm exits the skin to lay eggs, wrap it around a twig slowly.
Do not want to break the worm or use anti-parasites because the body may go into an anaphylactic reaction.
Presentation and treatment for a Black widow bite.
Bite releases a peripheral neurotoxin that causes muscle cramps, chest pain, nausea, vomiting, visual disturbance. Eventual cardiac or respiratory failure is fatal.
Tx: Antivenin (Abs to the venom usually obtained from hyperimmunized horses)
Presentation and treatment for Brown Recluse bite.
Bite introduces necrotoxin. Local tissue erythema and necrosis occurs. Treatment just involves keeping bite site clean to prevent secondary infection.
Describe the two scorpion toxins.
- Hemorrhagic/Hemolytic: causes local reactions, burning and radiating pain, welling, discoloration and necrosis.
- Neurotoxin: systemic effects, chills, muscle spasm, salivation, tachycardia, seizure, death
Treatment for scorpion stings.
Antvenin or analgesics for the pain
Condition that causes “interdigital itching”.
Scabies, caused by Sarcoptes scabiei mites. Females burrow into skin, lay eggs
What is Norwegian or Crusted Scabies?
Scabies infection in IC patients that leads to generalized dermatitis with extensive crusting and scaling.
Treatment for scabies.
Permethrin cream
Mites that infest hair follicles.
Demodex folliculorum mites
Bug that bites causing intense pruritic pain where clothing is tight or restricted.
Chiggers
-also a vector for scrub typhus
What is Tick Paralysis
Ascending flaccid paralysis, fever, general intoxication. It may lead to respiratory compromise and death.
What is Myiasis?
Maggots that live parasitically in human tissue.
Most important Myiasis.
Dermatobia hominis (human botfly) -usually the fly lays eggs that attach to mosquitos, the mosquitos bite a human and the eggs are deposited on the skin near the bite site. The eggs hatch and the maggots crawl into the bite.
