Cryptosporidiosis

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. After exposure, the incubation period ranges from 1 to 12 days (median 7 days). In people with HIV , 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. Cryptosporidium oocysts are present in most surface waters (e.g. rivers, streams, and lakes) throughout the United States, and have shown resistance to chlorine. Oocysts are also difficult to remove by with filters. Epidemiological studies have shown that municipal water supplies, camping, swimming, direct contact with feces while caring for an infected person, or association with kittens, puppies and young livestock are the most frequently identified risk factors.

Cryptosporidiosis in Florida and the U.S. has a seasonal and cyclical trend. Following a sharp increase in cases in 2014 in all genders, races, and ethnicities, cases decreased in 2015, and remained steady through 2019. Cases decreased in 2020 and 2021 and then increased in 2022 to similar counts seen in 2015-2019. Incidence is highest in 1- to 4-year-olds followed by 75-84-year-olds.

During the past two decades, Cryptosporidium has become recognized as one of the most common causes of waterborne disease (recreational water and drinking water) in humans in the U.S. Cryptosporidiosis incidence peaked in 2014 when there were six waterborne outbreaks investigated, including 134 cases associated with swimming pools, a recreational water park, and kiddie pools. Additional community-wide outbreaks in 2014 were associated with person-to-person transmission and daycares.

There were no food or waterborne disease outbreaks due to Cryptosporidium in 2019 or 2020.  In 2021 there was an outbreak of Cryptosporidium linked to calves and no food or waterborne disease outbreaks due to cryptosporidium in 2022. Clusters of illness were reported and associated with person-to-person transmission, travel, daycares and contact with animals.

Data Summaries for Common Reportable Diseases/Conditions

CDC - Parasites - Cryptosporidium

Current Information

The CDC has a resource CDC Healthy Water  that will help local health departments and water utilities deal with Cryptosporidium in community water supplies. This webpage is available at https://www.cdc.gov/healthywater/ and provides information on drinking water, healthy swimming and health promotion materials focusing on community water treatment, and preventing waterborne germs at home. 

Resources

• Florida Department of Health, Cryptosporidiosis, Florida Morbidity Statistics. 2019-2020 pp. 38-39

• CDC, Outbreak of Cryptosporidiosis at a Day Camp-Florida MMWR Vol.45/No.21 May 31,1996; 42-44.

• Heymann, D. (2015). Cryptospordium. In Control of Communicable Diseases Manual (20th ed., pp.136-139) Washington DC: American Public Health Association

• Juranek, DD, Cryptosporidiosis: Sources of infection and guidelines for infection prevention. Clinical Infectious Diseases 1995;21(Suppl) S57-6