Cryptosporidium parvum is an intracellular protozoa that is spread by the fecal-oral route. Ingested oocysts excyst in the gastrointestinal tract and replicate in epithelial cells, usually in the small intestine. It is common in many developing countries and has been associated with epidemic spread in the United States and Europe..
Risk Factor
Higher Risk
Lower Risk
water source
untreated environmental water, contaminated community sources
bottled water, high grade municipal sources
economic status
low
high
sexual preferences
anal intercourse, oral sex
protected
immune status
immunocompromised
immune competent
household pets
less than 6 months of age, from commercial breeder or pet shelter, previous stray, with diarrhea
older pet in good health with no or limited outside exposure
Risk of epidemic spread:
(1) day care centers
(2) swimming pools
(3) contaminated public water supplies
(4) within households
(5) in health care settings
(6) contaminated ice machines
Other features:
(1) Seroprevalence for antibodies to Cryptosporidium increases with age in endemic countries.
(2) The presence of infection with Cryptosporidium should prompt an evaluation for other enteric pathogens, and vice versa.
(3) The oocysts are resistant to chemical water purification techniques but may be removed by sand filtration.
(4) Infections in immunocompromised patients may be severe and extra-intestinal. AIDS patients infections may involve the gallbladder, pancreas and respiratory tract.
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