What is cryptosporidium
Cryptosporidium is a parasite (a tiny organism) that causes an illness or disease called cryptosporidiosis affecting people and some animals, particularly farm animals. It can be found in the intestines and faeces of infected humans and animals, and may contaminate lakes, streams and rivers, swimming pools, untreated or poorly treated water, food, especially raw milk and fresh produce, and objects such as farm gates and outdoor boots and clothing.
Who is at risk
Anyone can get cryptosporidiosis, but it is most common in children aged between 1 and 5 years.
Others at risk include people:
- who handle infected livestock or their faeces (poo)
- exposed to human faeces through caring (such as changing nappies, toileting young children) or through sexual contact
- who drink from untreated, unprotected water supplies or swallow contaminated recreational waters (lakes, rivers, streams, swimming pools or splash pads)
- who travel to countries where these exposures are likely
It can be a serious illness in people who have immune systems that are not working properly.
How you get cryptosporidiosis
You can get cryptosporidiosis directly from another person or animal by touching faeces, for example when changing a nappy or petting a lamb and putting your hands near or in your mouth without washing them thoroughly.
You can also get cryptosporidiosis from swimming in or drinking contaminated water. Occasionally you can be infected by eating contaminated food, including unwashed or unpeeled vegetables or salads or drinking contaminated raw milk. Cryptosporidium in manure can contaminate fields, rivers, and crops.
Symptoms of cryptosporidiosis
Symptoms include profuse watery diarrhoea, stomach pains, nausea or vomiting, low-grade fever and loss of appetite which can lead to dehydration and weight loss.
Symptoms usually last for about 2 weeks but can be longer, especially in people with weak immune systems. During the illness, you might think that you are getting better and have shaken off the infection but then it returns a couple of days later before you fully recover. As symptoms are similar to many other tummy bugs, the only way to know you have cryptosporidium is for a doctor to ask for a sample of your faeces to be tested in a laboratory.
How to avoid getting and passing on cryptosporidiosis
Everyone should take the following steps to prevent becoming infected with a tummy bug including cryptosporidium.
Wash your hands thoroughly with soap and warm water:
- before preparing and eating food
- after handling raw food
- after going to the toilet or changing a baby’s nappy
- after working with, feeding, grooming or playing with pets and other animals
Help young children to wash their hands properly.
Always wash and/or peel fruits and vegetables before eating them.
Do not drink untreated water.
Do not consume ice or tap water in countries where the water supply might be unsafe.
Avoid swallowing water in lakes and swimming pools.
You should pay special attention to hygiene during farm visits, washing hands after any contact with animals, and eating only in designated areas.
Cryptosporidiosis is highly infectious, so you need to be very clean around your home for at least 48 hours after your symptoms stop. You are infectious to other people while you are ill and have symptoms. In addition to the above hygiene practices, you should also take the following steps to prevent exposure to cryptosporidium and to avoid passing the illness to others.
You should:
- wash all dirty clothes, bedding and towels on the hottest possible cycle of the washing machine
- make sure that everyone has their own towel and that they do not use anybody else’s
- clean toilet seats, toilet bowls, flush handles, taps and wash hand basins after use with detergent and hot water, followed by a household disinfectant
- not go swimming or take your child swimming while suffering from diarrhoea and for 2 weeks after the diarrhoea has stopped
- not prepare food for others until you have been symptom-free for at least 48 hours
You can pass cryptosporidium in your faeces for several weeks even if you no longer have symptoms.
How to treat cryptosporidiosis
There is no specific treatment for cryptosporidiosis. Most people with a healthy immune system will recover within one month. It’s important to drink plenty of fluids as diarrhoea or vomiting can lead to dehydration and you can lose important sugars and minerals from your body.
Staying off work or school
While you are ill and have symptoms, you are infectious and should stay off work or school. You should not return to work or school until you have been free from diarrhoea and/or vomiting for 48 hours.
You should tell your employer you have had cryptosporidiosis if you work with vulnerable groups such as the young, the elderly, those in poor health, or if you handle food.
UKHSA and cryptosporidiosis
The UK Health Security Agency (UKHSA) provides advice on controlling outbreaks. We look for the source of the infection so that we can help to prevent other people from becoming infected. We also monitor outbreaks of cryptosporidiosis and look for any patterns or trends which show possible connections between the people who are affected.
If you are concerned about your health or your children, please contact your GP.
If you have any further questions, please contact your local health protection team.
Find your local health protection team in England
Published 1 November 2023
