Parasites Flashcards
Protozoan Diseases
TROPHOZOITE (A term for the live adult protozoa)
Malaria, African Sleeping Sickness
Cysts, spore, or “eggs” are non-adult forms
MOST OF THESE DISEASES ARE SPREAD BY THE FECAL-ORAL ROUTE
GIARDIASIS
Giardia lamblia, a flagellate, is a common pathogenic protozoan.
Infects duodenum and jejunum of humans.
Causes the disease giardiasis.
GIARDIASIS Treatment
Metronidazole (Flagyl) 250mg twice daily for 5 days will clear over 90% of Giardia lamblia infections.
Oral tinidazole and nitazoxinide are alternatives.
Cryptosporidiosis
A coccidian protozoan parasite which causes the disease Cryptosporidiosis
Associated with contaminated water supplies
One of the most common causes of waterborne illness in the United States
Cryptosporidium: Site of infection
Epithelial cells of the gastrointestinal tract
Has affected other tissues such as respiratory tract tissues and conjunctiva of the eye
Cryptosporidium Diagnosis
examining stool specimens, (3 stools) Microscopy with an acid fast stained stool smear is usually diagnostic
Enzyme immunoassay for greatest sensitivity and specificity or molecular methods using PCR
Intestinal Amoebas Strains
Entamoeba histolytica
Dientamoeba fragilis
Amoebiasis- Diagnostic Laboratory Tests
Stool Specimens
Fluid feces— Fresh and warm for immediate examination for trophozoites, After a saline purge for cysts and trophozoites.
Formed feces for cysts
Serology is available
EIA (Enzyme Immunoassay)
Amoebiasis- Treatment
Asymptomatic intestinal infection –
Paromomycin
Symptomatic disease –
Paromomycin as above AND Metronidazole
Malaria
Vector (Mosquitoes)
Five species infect humans…Plasmodium falciparum most serious
Plasmodium vivax most common
Parasites multiply within liver cells and RBCs
Malaria-Treatment and prophylaxis
Chloroquine *(most strains of Plasmodium show resistance) Atovaquone & proguanil (Malarone) Hydroxychloroquine(Plaquenil) Doxycycline Mefloquine(Larium)*
Chloroquine and Mefloquine are safe with pregnancy
Toxoplasma gondii - Toxoplasmosis
death attributed to food borne illness in the US
Oocysts develop in the cat GI tract, pass into the gut lumen of the cat, and pass out via the feces.
These cysts can then be ingested by other creatures, including humans (i.e. changing litter box of pet cat)
Toxoplasmosis - Symptoms
Immune competent patients – most will be asymptomatic
Immune compromised patients - can cause: hepatitis, pneumonia, blindness, and severe neurological disorders.
Toxoplasmosis-treatment
Acute infections can be treated with a combination of pyrimethamine orally once a day with a sulfonamide and Leucovorin
For use in pregnancy, spiramycin (Rovamycine) continued until delivery
Pinworm (Enterobius vermicularis)
Spread: Fecal- Oral route; self contamination and internal reinfection
Worms resides in cecum, colon… crawl out of anus at night
Symptoms: ITCHY BUTT! Squirming when sitting
Rarely, worms get in vaginal canal
