Cryptosporidiosis

Cryptosporidiosis is a diarrhoeal disease caused by the parasite, Cryptosporidium, which infects the intestine. Cryptosporidium infections have been reported in humans and in a variety of farm, pet and native animals. Although there are several species of Cryptosporidium, only two species, Cryptosporidium parvum and Cryptosporidium hominis, are thought to cause infection in humans.

Cryptosporidiosis has been notifiable to the NSW Health Department since 1996, and is a common cause of waterborne disease in NSW. Several hundred cases are usually reported in NSW each year and the number of cases tends to increase in the warmer months.

The most common symptom of cryptosporidiosis is watery diarrhoea. Other symptoms include stomach cramps, fever, nausea, vomiting and loss of appetite. Some people with the infection have no symptoms at all.

The first signs of illness appear between 1–12 days (average 7 days) after a person becomes infected. Symptoms may come and go, but they usually disappear in less than 30 days for people with healthy immune symptoms. People with a weak immune system may have more severe symptoms that can last for many weeks.

The cryptosporidiosis parasite is present in the faecal matter of infected humans and animals. The disease is passed on when the parasite is ingested. Transmission most often occurs through:

• person-to-person contact, particularly in families and among small children (for example, in child care centres)

• drinking contaminated water

• swimming in contaminated pools

• handling infected animals or their manure

• food (in rare cases)

A person is most infectious when they have diarrhoea, but the parasite may be excreted for several weeks after symptoms disappear.

People who are most likely to become infected with Cryptosporidium include:

• people in close contact with others who have cryptosporidiosis

• children who attend day care, including children in nappies

• parents of infected children

• child care workers

• swimmers who accidentally swallow swimming pool water

• people who drink untreated water (for example, from contaminated rivers, lakes, dams, wells or streams).

• travellers to developing countries

• people who work with animals

• men who have sex with men.

People with weakened immune systems are at risk for more serious disease and should see their doctor if symptoms develop.

To avoid catching cryptosporidiosis people should:

• always wash hands thoroughly with soap and water after using the toilet, handling animals or their manure, contact with faeces, changing nappies, working in the garden and before preparing food or drinks

• avoid drinking untreated water (e.g. from rivers, lakes, streams or dams – boiling water from these sources for one minute will kill germs, including cryptosporidiosis)

• avoid swallowing water when swimming

• avoid swimming in natural waters (e.g. rivers, creeks, dams, surf) within a week after heavy rain events

• in developing countries avoid food or drinks that may be contaminated (e.g. raw vegetables, tap water or ice made from tap water)

To avoid spreading cryptosporidiosis, people with cryptosporidiosis should:

• not swim for at least two weeks after the diarrhoea has stopped

• not share towels or linen for at least 2 weeks after the diarrhoea has stopped

• keep small children who have diarrhoea home from school, preschool, childcare or playgroup until 24 h after the diarrhoea has completely stopped

• do not handle food for at least 48 h after the diarrhoea has stopped

If you have diarrhoea the only way to tell if it is cryptosporidiosis is by going to a doctor and having a stool specimen taken.

There is no specific treatment for cryptosporidiosis. Drink plenty of fluids to avoid dehydration.

Laboratories are required to notify cases of cryptosporidiosis to the local Public Health Unit under the Public Health Act, 1991. Public Health Units investigate cases, and review possible sources of infection to prevent further spread.

Please contact your doctor, local public health unit or community health centre.