The arrival of hot weather is an unbeatable breeding ground for norovirus, a gastrointestinal virus which spreads very easily and generally results in nausea, vomiting, liquid or soft diarrhoea, generally feeling unwell and fever. The symptoms normally last for 24 to 48 hours and then the patient recovers.
Medical experts say they see more cases of norovirus for two or three weeks once the heat begins, and then the situation returns to normal.
Norovirus is highly contagious. It is spread through food or water that is contaminated during preparation or through contaminated surfaces. It can also be spread by close contact with someone with the infection.
The diarrhoea, abdominal pain and vomiting normally start between 12 and 48 hours after exposure to the virus. The symptoms usually last for 24 to 48 hours, although they can go on for three days. Most people recover completely without treatment although some, such as young children, elderly people and those with other health conditions, can become dehydrated and need medical attention.
Norovirus spreads most often in enclosed spaces where there are a lot of people, such as hospitals, care homes, nursery schools, schools and cruise ships. Some people catch the virus but experience no symptoms, but they are still infectious and can pass it on to others.
To prevent contagion, it is important to wash your hands with soap and water for at least 20 seconds, especially after going to the bathroom, changing a nappy, before handling food and before eating and drinking. Hand sanitisers are not effective at preventing norovirus, experts say.
They also recommend washing fruit and vegetables before eating them, and cooking shellfish well. Any surfaces which may have been contaminated should also be disinfected.
Any adult who catches the virus is recommended to stay at home and not go to work and children should not go to school or nursery.