Parasites 3 Flashcards
What is the organism and transmission of Amebiasis?
Entaoeba histolytica, related E. disbar
lives in the lumen of lumen and leads to invasion of tissue transmitted by ingestive (fecal/oral) or direct (anal sex) common with human waste used as fertilizer or faulty water purification
infective acid-resistant cysts are ingested, attach and divide in the colonic mucin resistant cysts form in the large intestine are shed in feces but can also penetrate the mucosal layer leading to invasive disease
What are the different pathological outcomes of E. histolystica?
carriers can be chronically asymptomatic and shed millions of cysts a day
dysentery occurs, can be accompanied by invasion of colonic epithelium and submucosal ulcers
invasion is rare and not always associated with dysentery; dissemination can occur throughout the body, mostly the liver (and lungs)
may be acquired immunity in endemic areas
How is amebiasis dx and tx?
cysts present in stool; trophozoites and cysts in blood diarrhea, trophozoites; stool antigen and PCR to confirm
tx. with metronidazole or tinidazole for invasive tissue phase or paromomycin for luminal phase
How is giardiasis transmitted?
is intestinal bug that its reservoir is wild and domestic animals and it transmitted via ingestion of contaminated water/ oral-anal sex (infectious dose is very low) leading to encystation in the upper and large intestines with excretion of cysts
common in day care center, nurseries and ski resorts
What is the symtoms, dx. and tx. of giardiasis.
asymptomatic to explosive diarrhea, flatus, belching, cramps and nausea; self cure in 1-4 weeks
dx. presences of cysts but excretion is intermittent, confirm with guard antigen ELISA on stool specimen
tx. metronidazole, tinidazole or nitazoxanide
paromomycin for pregnant women
What organisms are contained in the apicomplexan group?
cyrptosporidium, palsmodium and toxoplasma
What are the characteristics of apicomplexan parasites?
obligate intracellular parasites (hidden from the immune system)
complex life cycles that alternate between asexual and sexual reproduction (within the intestinal epithelium of the definitive host)
Name the organism and route of transmission for cryptosporidiosis.
C. hominid and C. pram (both shared with cattle)
infection stays luminal within the intestine transmitted from the reservoir of wild animals/livestock via fecal/oral (cysts are very robust)
US transmission often associated with institutions and faulty water purification; shedding of oocytes highest in acute phase
self limiting infection except in immunocompromised
dx: acid fast stain of cysts in stool- red ‘cup and saucer’
tx. oral rehydration, especially in immunocompromised
short course of nitazoxanide for immunocompromised in adults
What are the signs of cryptosporidosis, and how is it dx and tx?
3 or more loose water bowel movements in 24h, PROFUSE watery diarrhea
How is toxoplasmosis transmitted?
definitive host in cats, intermediate hosts are any warm blooded animal transmit
What is the symptoms and tx. of toxoplasmosis.
acute infection: often asymptomatic
rapid control by cellular mediated immunity and latent infection; immunodeficient cannot control primary/reactivated infection;
also in utero infection causing from mild to severe consequences, chrorioretinitis, still birth, miscarriage, retardation and birth defects
tx: essential for immunocompromised or activate chrorioretinitis: pyrimethamine/sulfaonamide’ pyrimethamine/clindamycine
HIV prophylaxis TMP/sulfa
spiramycin if pregnant not FDA
Discuss how serology is used to describe infection as either acute or chronic immunity.
dx serology, indirect immunofluorescence (IFA)
acute: IgM
chronic immunity IgG
How do we distinguish toxoplasma with lymphoma?
multiple ring enhancing rings in the brain is suggestive of toxoplasmosis
What are the consequences of congenital Toxoplasma infections.
ocular lesions
hydrocephalus
