General Information and Symptoms
Cryptosporidiosis in humans is caused by infection with a
protozoan parasite classified
as Cryptosporidium parvum. Oocysts, the infective stage
of this parasite, cause an illness that presents as watery
diarrhea with abdominal cramps, possibly accompanied by fever,
nausea, vomiting, and myalgias.1 After exposure, the
incubation period ranges from 1 to 12 days (median 7 days). In
AIDS patients, the
illness varies from asymptomatic carriage to
severe watery diarrhea with weight loss, electrolyte imbalance
and dehydration. Duration of illness can range from days to
months, but usually resolves within 2 weeks in otherwise healthy
patients. Shedding of oocysts, however, can occur
up to 2 weeks
after the patient is clinically well.
Oocysts may be transmitted via contaminated food or water, by direct
contact with infected livestock or pets, and from person to
person by the fecal-oral route.2
Cryptosporidium oocysts are present in most surface waters
(i.e. rivers, streams, and lakes) throughout the United States,
and have shown resistance to chlorine. Oocysts are also
difficult to remove by filters. Epidemiological studies have
shown that municipal water supplies, camping, swimming,
association with kittens, puppies and young livestock or direct
contact with feces while caring for an infected person prior
were the most frequently identified risk factors.
Cryptosporidiosis in Florida
Cryptosporidiosis has been reportable in Florida since 1992,
when 27 cases were reported. Case reporting increased somewhat
in 1993 (54) and 1994 (86), but more than tripled in 1995 (1.9
per 100,000) when 275 confirmed cases were documented.3
Since 2000, the annual average of cryptosporidiosis cases
acquired in Florida has remained near 130 cases per year.
Incidence is highest in children less than five years old and
males 30 to 39 with rates in non-whites of both sexes more than
twice as high as whites. Most cases occur sporadically with the
incidence highest in Dade, Broward and Palm Beach Counties.
However, a waterborne outbreak at a school day care facility in
Alachua County involving 77 individuals, mostly children, was
investigated in 1995.4
The CDC has recently produced a handbook entitled Cryptosporidium and
Water that will help local health departments and water
utilities deal with Cryptosporidium in community water supplies.5
Copies can are available online at
http://www.cdc.gov/ncidod/diseases/crypto/crypto.pdf or may
be obtained by writing to: Centers for Disease Control and
Prevention, National Center for Infectious Diseases, Division of
Parasitic Diseases, Mailstop F-22, 4770 Buford Highway N.E.,
Atlanta, GA 30341-3724.
Klass, J., Cryptosporidium. In Clinical and Pathogenic
Microbiology 2nd edition, Howard, BJ, et al., Mosby-Year Book Inc., St.
Louis, Mo. 1994; pp. 704-07.
Juranek, DD, Cryptosporidiosis: Sources of infection
and guidelines for infection prevention. Clinical Infectious Diseases
Florida Department of Health, Cryptosporidiosis,
Florida Morbidity Statistics.1995 pp. 32-34.
CDC, Outbreak of Cryptosporidiosis at a Day Camp-Florida MMWR Vol.45/No.21 May 31,1996;42-44.