Agricultural Disaster Preparedness and Recovery, Food Safety November 21, 2011 Print Friendly and PDF


This is a stool smear micrograph revealing Cryptosporidium parvum as the cause of this patient’s Cryptosporidiosis. Image courtesy of CDC/ Dr. Peter Drotman.

Members of the Cryptosporidium genus are protozoa (single-celled animals) that live by invading other cells and are therefore parasites. “Crypto” organisms have a protective outer covering that makes them resistant to most disinfectants and able to survive outside of hosts for a long time.

Cryptosporidium species can be found in drinking water, recreational water (swimming pools, hot tubs, reservoirs, lakes, streams, etc.) and any other water source that could be contaminated with human or animal feces.

Cryptosporidiosis is a diarrheal disease often caused by C. parvum. Symptoms of this illness can include severe watery diarrhea, weight loss, dehydration, abdominal pain/cramps, nausea, vomiting, and fever, although some infected persons show no signs of illness. Occasionally, the parasite can also invade the respiratory system, causing coughing and fever in addition to gastrointestinal issues.

Transmission is fecal-oral, meaning the infective organism is passed out in the feces of an infected host and picked up by the next host through oral contact with any food, water, soil, or surface contaminated with infected feces. Those most at risk of contracting cryptosporidiosis include the very young, the elderly, and the immuno-suppressed. Other risk groups include those who contact untreated water (hikers, swimmers, etc.), childcare workers, international travelers, and parents of infected children. Humans can transmit the disease to other mammals and vice versa.

Signs of illness usually begin two to ten days after ingestion of the parasite (average = seven days). Symptoms last one or two weeks and can even be cyclical. Diagnosis is made through microscopic fecal examination.

As with all cases of severe and/or prolonged diarrhea, affected persons should contact their health care providers. Management of cryptosporidiosis often focuses on rehydration. Most otherwise-healthy people will not need treatment.

Prevention of cryptosporidiosis includes personal hygiene and environmental sanitation practices.

  • Wash hands before handling or eating food
  • Wash hands after going to the bathroom
  • Wash hands after changing diapers
  • Do not go swimming if you have a diarrheal disease
  • Do not eat food that could be contaminated with the organism
  • Do not drink water that could be contaminated unless it has been boiled for at least one minute or run through filter with a pore size of no more than one micron.


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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.