parasitology Flashcards
what are parasites
eukaryotes; chronic and prolonged course of infection; most of them have complex life cycles; exogenous to the human host
types of parasites
protozoa (unicellular: plasmodium sp.)
helminths (worms: tenia sp.)
exoparasites (arthorpods: lice)
cause and spread of malaria
protozoa: plasmodium falciparum, p. vivax, p. malariae, p. ovale
spread by the anopheles mosquito; definitive host; sexual cycle
developmental life stages of plasmodium spp.
mosquito stages; human liver stages; human blood stages
malaria symptoms
chills, fever, vomiting, headache
malaria etiology
mosquito bite introduces the protozoa into the host’s blood stream, protozoa infect and lyse red blood cells; causes anemia; lysed RBCs block blood vessels, leads to tissue death
trichomonas vaginalis
trichomonias; protozoa; sexually transmitted
trichnomoniasis
disease most common in women
symptoms: in men (rare) - burning after urination, mild discharge
in women - greenish-yellow discharge with a strong odor, itching, painful urination
toxoplasma gondii
protozoa; cats are the definitive host; sexual cycle of the parasite occurs in the cat
transmission of toxoplasma gondii
transmission occurs to humans; water and food contaminated with oocysts; changing cat litter box; eating undercooked meat of animals with tissue cysts; transplacentally; blood transfusions and organ transplants
toxplasmosis infection
in healthy people is mild
in immunocompromised patients: more dangerous
the primary dange is congenital infection (transplacental): stillbirth, child is born with brain damage/visual problems
water-born parasite species
protozoa - entamoeba histolytica; cryptosporidium sppp. giardia lambia
transmission of water-borne parasites
drinking water contaminated with animal wastes; swimming pools; resistant to chlorination
2 types of amebiasis
intestinal - cysts pass through the stomach where the exposure to gastric acid stimulates the release of the pathogenic trophozoits in the duodenum; the trophozoites cause necrosis in the large intestine
extraintestinal - mainly in the liver
cryptosporidium spp.
cryptosporidosis
cryptosporidosis
protozoa (c. hominis, c. parvum)
invade the epithelial cells of the intestines causing watery diarrhea, stomach pains, cramps and fever
giardia duodenalis
giardiasis
giardiasis
protozoa (giardia lamblia); flagetllate; attaches to the intestinal villi with an adhesive disk, resulting in localized tissue damage
