Thirteen students of a veterinary college in Kerala’s Wayanad district have tested positive for norovirus, Kerala Health Minister Veena George said on Friday.

The students were living outside the hostel, college authorities told Hindustan Times. Their samples were sent to the National Institute of Virology, Alappuzha, which confirmed the presence of the virus.

According to the United States’ Centers for Disease Control and Prevention, norovirus can spread from one infected person to another or through contact with contaminated surfaces or food. The most common mode of transmission is through contaminated food or water.

It causes diarrhoea, vomiting, stomach pain and gastrointestinal problems, especially in children. The virus is “highly contagious”, notes the CDC.

While the virus is not known to be fatal and is treatable, there is so far no vaccine to prevent it.

The Kerala health department said that the outbreak was being contained locally.

Health Minister George on Friday issued guidelines on preventive activities after the 13 students tested positive for the virus. The guidelines advise infected people to rest at home, and drink oral rehydration solutions and boiled water, ANI reported.

The guidelines also advise people to wash their hands well with soap and water before eating and after using the toilet. “Those who interact with animals should pay special attention,” they state.

The health ministry’s guidelines further advise people to use fruits and vegetables only after thoroughly washing them. Also, it urges people to eat sea fish and shell fish such as crabs and mussels only after they are well-cooked.

George said that there is currently no cause for concern, but asked people to be vigilant, according to ANI. “With proper prevention and treatment, the disease can be cured quickly,” she said. “Therefore, everyone should be aware of the disease and its means of prevention.”

She noted that authorities are carrying out super chlorination of water, and noted that sources of drinking water need to be hygienic.