Cryptosporidium is a microscopic parasite and is protected by an outer shell that allows it to survive for long periods of time. It is very resistant to chlorine disinfection.
According to Health Protection Scotland, cryptosporidium is an infection that affects many animals including sheep, cattle, cats and dogs as well as humans. Human infection may be acquired from other people, from animals and from drinking water contaminated from either agricultural or human sewage sources.
Those at increased risk of disease associated with infection include people with occupational exposure to animals, such as farmers, veterinarians and slaughterhouse workers, and people who use swimming pools.
Immunocompromised people are at greater risk of severe disease. Cryptosporidium is the fourth most commonly identified cause of human gastrointestinal infection in the UK and incidence rates are highest in young children, and during the spring and summer months.
Health Protection Scotland say the main clinical features include diarrhoea, which may contain mucus, but rarely blood, lasting from two days to four weeks, which may be accompanied by vomiting (especially children), anorexia and abdominal pain. The infection is usually more severed and protracted, and may be life threatening, in those who are severely immunocompromised, such as those with AIDS.
