Gaston Farm near Slindon has been shut as a precaution following a lambing event.
At least 14 people were affected. One child needed hospital treatment.
Specialists from Public Health England South East are warning people to be aware of a serious stomach infection caused by cryptosporidium.
They say the outbreak is most likely the result of contact with animals. The farm says its priority is ensuring visitors are safe.
Dr Kevin Carroll- Public Health England tells us how germs could spread.
The farm says its priority is ensuring it's safe for visitors.
What is Cryptosporidium?
Cryptosporidium is a genus that causes a respiratory and gastrointestinal illness i.e. vomiting and diarrhoea in those affected.
Anyone suffering from diarrhoea symptoms is being advised not to attend school or childcare settings for 48 hours after recovery.
If you have been diagnosed with cryptosporidium you must not swim until at least two weeks after the symptoms have ended.
Cryptosporidium spreads easily in swimming pools because it is not killed by chlorine used to treat the water and you may continue to excrete cryptosporidium for up to two weeks after you have recovered.
Cryptosporidium is highly infectious so as with all gastrointestinal illness it is important to be scrupulously clean around your home.
Clean toilet seats, toilet bowls, flush handles, taps and wash hand basins after use. Make sure all members of your household wash their hands thoroughly with soap and hot water after going to the toilet and after handling soiled clothing or bedding. Make sure that everyone has their own towel and that they do not use anybody else's. Wash all soiled clothes and linen on as hot a machine wash as possible.