Infection of large intestine by parasite,<unk> 
Large, ciliated protozoan
Simple life cycle: dormant cyst to trophozoite to cyst
Reservoir host is pig (asymptomatic)
Pig sheds feces with cysts => contaminated water and food => ingested by humans => parasite resides in large intestine
Parasite usually resides in lumen of intestine but can also penetrate mucosa
Opportunistic infection
Human-to-human transmission via fecal-oral route as well
Worldwide prevalence 0.02-1% and found wherever pigs are found
Risk factors:
Close contact between human and pigs
Lack of appropriate waste disposal that can contaminate drinking water sources
Subtropical/tropical climates (warmth and humidity favor survival of cyst)
Compromised immune system, elderly, malnourished, alcoholics
Large, ciliated protozoan
Simple life cycle: dormant cyst to trophozoite to cyst
Opportunistic infection
Close contact between human and pigs
Lack of appropriate waste disposal that can contaminate drinking water sources
Subtropical/tropical climates (warmth and humidity favor survival of cyst)
Compromised immune system, elderly, malnourished, alcoholics
Balantidium coli
Entamoeba histolytica
Bacteroides fragilis
Shigella
Giardia lamblia
Salmonella
Enterobius
Campylobacter