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Kingdom Protista
- this is a parasite family
- unicellar, eukaryotes
- classified into 4 subphylas based on their means of locomotion: ameobas, ciliates, flagellates, and sporozoa
- have 2 forms of life cycle: trophozoite and cyst
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Sarcodina
- it is an amoeba class
- moves by means of cytoplasmic protrusions called pseudopodia
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Entamoeba hystolytica
- causes amoebic dysentery AKA amoebiasis
- produces bloody diarrhea
- endemic in tropical and subtropical areas (Central and South America, Mexica, Phillipines, and Mexico)
- this parasite feeds on RBC in the large intestine
- Dx: exam stool speciman for O&P (look for worm eggs)
- Tx: Flagyl
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Mastigophora
- is in the class flagellates
- move by flagella
- 2 groups: intestinal flagellates and hemoflagellates
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Giardia intestinals (lambia)
- it is an intestinal flagellate causes giardiasis
- most common in our area
- AKA Beaver Fever
- 2 forms: Troph (motile) and Cyst (non-motile)
- Trophs: pear-shaped, has sucking disk to resist peristalsis, have a pair of nucleii that looks like eyes, several pairs of flagella
- Cyst: is a resistant resting stage and has axostyles
- Disease: frothy green diarrhea, flatulence, dehydration, cramping in upper GI tract
- Dx: stool speciman under O&P for cyst eggs. If negative, perform a string test for troph. Blood test for antibody
- Tx: Flagyl
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Trichomonas vaginalis
- Disease: men - often asymptomatic, but the parasite lives on urethral surfaces, prostate or seminal vesicles; women - lives in the genital mucosa, can cause itching frothy discharge,vaginitis, and urinary problems
- Transmission: can be a STD or live on fomites
- Dx: wet prep of vaginal secretions so can be found in a pap smear-look for active motile trophs with undulating membrane
- Tx: Flagyl
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Hemoflagellates
- live in bloodstream or parasitic tissue
- transmitted by biting insects
- parasites: Leishmania
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Leshmania spp.
- transmitted by the sandlfly insect---found in the desert
- cutaneous "Baghdad boil"
- infects WBC and causes fever and enemia
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Plasmodium spp
- is a sporozoa -- no motility
- Diseases: causes malaria , fever, chills, fatigue, periodic cyclic fevers, and can cause liver damage
- Dx: see infected RBC in blood smears called ring form
- Tx: Quinine drugs
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Toxoplasmic gondii
- Disease: mild, self limiting disease and often asymptomatic. Only causes severe congenital defects if pregnant
- Transmission: found in cat, cow, sheep feces; transmitted by contact with cat feces or eating undercooked infected beef or lamb
- Dx: taxoplasmosis antibodies
- Tx: no tx, mild sx
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Cryptosporidium spp
- Disease: intestinal parasite infects intestinal lining--> causing diarrhea for 1-2 weeks, severe dehydration even death
- Transmission: fecal-oral route, contaminated water with oocytes
- Dx: FA smear with stool
- Tx: no effective treatment
- Prevention: filtration of water to remove cryptosporidium as chlorine does not kill the species
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