Transmission

Cryptosporidiosis is a zoonosis. Infection is transmitted faeco-orally through person-to-person and animal-to-person routes or indirectly through environmental vehicles (e.g. contaminated water and food) (1).

• transmission commonly occurs when contaminated water is ingested e.g. - from oocysts contaminated recreational water sources (such as swimming pools and lakes) and drinking water supplies
• contact with infected individuals (particularly diapered children or in the child care setting) or infected animals (particularly pre-weaned calves) is an important cryptosporidiosis risk factor
• infective dose is very small and about two to ten oocysts are estimated to be sufficient to cause the disease
• foodborne transmission has been reported in association with unpasteurized apple cider, raw produce, including parsley, green onions, and chicken salad as well as transmission via ill food handlers (1,2)

Outbreaks have been reported in healthcare facilities and day-care centres, institutions, at open farms, within households, among bathers and water sports players in lakes and swimming pools, and in municipalities with contaminated public and private water supplies (1).

The Expert Advisory Group on AIDS has recommended that AIDS patients with a CD4 cell counts below 200 per mm3 be advised to boil water, from whatever source, before drinking it, as a measure to prevent waterborne cryptosporidiosis

Reference:

• (1) European Centre for Disease prevention Control (ECDC) 2012. Rapid risk assessment. Increased Cryptosporidium infections in the Netherlands, United Kingdom and Germany in 2012
• (2) Siberry GK et al. Guidelines for the prevention and treatment of opportunistic infections in HIV-exposed and HIV-infected children: recommendations from the National Institutes of Health, Centers for Disease Control and Prevention, the HIV Medicine Association of the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the American Academy of Pediatrics. Pediatr Infect Dis J. 2013;32 Suppl 2:i-KK4