Cryptosporidiosis

Description

Cryptosporidiosis is a parasitic infection caused by Cryptosporidium parvum and occasionally other species of Cryptosporidium. It is transmitted by ingestion of faecally contaminated food or water, including water swallowed while swimming; by exposure to faecally contaminated environmental surfaces; and by the faecal-oral route from person to person (e.g., while changing nappies (diapers), caring for an infected person, or engaging in certain sexual behaviours).

Occurrence

Cryptosporidiosis occurs worldwide.

Risk for Travellers

For travellers to developing countries, risk of infection is highest for those with the greatest exposure to potentially contaminated food or water.

Clinical Presentation

Symptoms include watery diarrhoea, abdominal cramps, vomiting, and fever. In immune competent persons, symptoms last an average of 6-10 days but can last up to several weeks. In persons with severely weakened immune systems, cryptosporidiosis can become chronic and can be fatal.

Prevention

No vaccine is available. To avoid contracting cryptosporidiosis, travellers should be advised to follow the precautions described in the section Risks from Food and Drink. Cryptosporidiosis is poorly inactivated by chlorine or iodine disinfection. Water can be treated effectively by boiling or filtration with an absolute 1-micron filter. Specific information on preventing cryptosporidiosis through filtration can be found in "Preventing Cryptosporidiosis: A Guide to Water Filters and Bottled Water" at http://www.cdc.gov/ncidod/dpd/parasites/cryptosporidiosis/factsht_crypto_prevent_water.htm.

Treatment

The FDA has approved nitaxozanide suspension (Alinia, Romark Laboratories) for treatment of cryptosporidiosis and giardiasis in children and nitaxozanide tablets for treatment of giardiasis in adults. Nitazoxanide tablets are a potentially useful treatment for immunocompetent adults with cryptosporidiosis.

Bibliography
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  • Guerrant RL. Cryptosporidiosis: an emerging, highly infectious threat. Emerg Infect Dis. 1997;3:51-7.
  • Kosek M, Alcantara C, Lima AA, et al. Cryptosporidiosis: an update. Lancet Infect Dis. 2001;1:262-9.
  • Roy SL, DeLong SM, Stenzel SA, et al. Risk factors for sporadic cryptosporidiosis among immunocompetent persons in the United States from 1999 to 2001. J Clin Microbiol. 2004;42:2944-51.
  • Taylor DN, Connor BA, Shlim DR. Chronic diarrhoea in the returned traveller. Med Clin North Am. 1999;83:1033-52.
  • Thielman NM, Guerrant RL. Persistent diarrhoea in the returned traveller. Infect Dis Clin North Am. 1998;12:489-501.
  • Nitazoxanide (Alinia)—a new anti-protozoal agent. Med Lett Drugs Ther. 2003;45:29-31.

- Caryn Bern

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