VIII-Parasitic SSTI Flashcards
life cycle of leishmania
infected person (parasite in macrophages) biten by sandfly that bites someone else
-reservoir: canines and rodents
cutaneous leishmaniasis agents
L. major/tropica/mexicana
mucotaneous leishmaniasis agents
L. braziliensis
cutaneous leishmaniasis prez
raised dry crusty lesions at site where parasite inoculated > slowly enlarges > ulcerates
mucocutaneous leishmaniasis prez
typical cutaneous lesion > ulcerates > severe disfigurement
@nasal mucosa and septum
onchocerca volvulus life cycle
river blindness
blackfly uptakes microfilariae from infected person and spread
-larvae dev into adults after years @subcutaneous nodules then migrate to tissues
onchocerca vulvulus prez
intense pruitic rash or if eye then sclerosing keratitis = hardening cornea
onchoceraciasis diagnosis
skin snips show microfilariae
treat with ivermectin to mass iradicate but repeated dosing required
life cycle of guinea worm
- lesion with worm comes in contact with water = microfilariae release
- crustaceans ingest
- people drink contaminated water
- larvae migrate thru tissue esp lower limbs
- blister forms when female worm ready to release larvae
dracunculosis agent
dracunculus medinensis (guinea worm)
-largest tissue dwelling nematode
diagnosing dracunculosis
wash out microfilariae from ulcer
-wind worm out on a stick
cutaneous larva migrans cause
Ancylostoma (hookworms) normally infect dogs and cats accidentally penetrate human skin so burrow deep into epidermis
cutaneous larval migrans prez
red serpentine pattern , intense inflamm resp, pruitic
-usually soles of feet
sarcoptes scabei life cycle
scabies mite (small arthropods) transferred to human thru direct contact > larvae hatch and burrow = superficial dermatitis
infestation
scabies prez
itching, short, serpentine, raised, lesions @webbing fingers, wrists, elbows, trunk
-can become hyperinfection from thousands of mites = norwegian/crusted scabies so crust hands, feet, body
diagnosing scabies
pick up female mites from skin scrapping
head lice cause
transmit thru physical contact/sharing head accessories
so school children yuck
P. humanus capitis
body lice cause
found on clothing of infected indivs but will move to body to feed
-spread direct physical contact/sharing clothes
pediculus humanus
crab lice
sexual contact spread so in pubic and perianal region hair (axillary and facial too)
phthirus pubis
diagnose lice
id lice or eggs in hair or seams of garments
lice treatments
products with insecticides - shampoo, lotion, cream + retreat to destroy newly hatched
-high heat washing clothing/bedding
-nit combs
human botfly cause
myiasis
infest tissue by larvae (maggots) of flies
-transmit by bite of diff arthropod
dermatobia hominis
human botfly prez
painful foul smelling exudate
bed bugs cause
*cimex lectularius *
hide during the day in mattresses, furniture then blood feeding at night
-not disease transmiting
bed bug prez
red itchy welts @ trunk and limbs
chagas disease
T. cruzi
spread by reduvid bug
-if chronic can infect cardiac muscle and myenteric plexus
trichinosis life cycle
- ingest undercooked contaminated swine, boars
- Trichinella spiralis encysted larvae released into stomach > mature in small intestine
- will penetrate striated muscle and encyst ‘nurse cells’ =
appears as spiral in muscle
trichinosis prez
initial abdom pain, vomit, diarrhea > muscle pain, fever, eosinophilia, myocarditis, periorbital edema
lung fluke life cycle
paragonimus westermani transmitted thru ingestion of freshwater crabs or crayfish, snails > excyst in stomach and GI > lung parenchyma > eggs escape fibrotic cyst to be coughed up in sputum/swallowed/feces
lung fluke prez
cough + blood tinged/rusty sputum + fever
eggs are coughed up and swallowed
