The Nipaj virus infected 18 persons before it was localized and contained.
Medics wearing protective gear examine a patient at a hospital in Kozhikode in the southern state of Kerala, India May 21, 2018.
Since these bats feed on any fruit they can find, there's a risk of exports of many fruits getting affected. Rajeev Sadanandan, Health Secretary issued the advisory, which said that although Kerala is safe if tourists are being cautious they were advised to avoid these four districts.
One of the 10 victims was a nurse who died on Monday after treating a Nipah patient in hospital. Her body was cremated soon after her death over fears the virus could spread; her family wasn't able to see her.
Meanwhile, a health ministry official said that as all means of transport can't be blocked, the state would have to prepare itself to take preventive measures. Two "control rooms" in the worst-hit Kozhikode district have been set up to closely monitor the spread of the virus.
State National Health Mission Director Keshvendra Kumar, who reviewed the situation in the district, said "ribavirin" - a medicine that has shown to be effective against Nipah virus - has been procured by Kerala Medical Services Corporation Ltd.
State health minister KK Shailaja told ANI that the Centre will send an expert team to the state within 2 days. Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours.More news: Iran seeks guarantees as JCPOA signatories meet to save deal
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Earlier, cases of Nipah virus were reported from West Bengal's Siliguri in 2001 and Nadia district in 2007 and around 47 deaths were reported.
There has not yet been an official statement from Public Health England about travel to Kerala, but the risks to travellers are likely to be extremely low.
The Nipah Virus began in the northern district of Kozhikode at the weekend that has now spread to the neighbouring Malappuram district in Kerala.
But this is not the first outbreak of Nipah virus in India.
According to the World Health Organization, between 1998 and 2015, more than 600 cases of Nipah virus human infections were reported.
In 2004, residents in Bangladesh also caught the infections after they ate contaminated fruits or consumed products such as raw date palm juice that were contaminated by saliva or urine of infected fruit bats. The virus also transmits from humans to humans.