The deadly Nipah virus has killed two people in the southern Indian state of Kerala.
Three people, including a child, have tested for the virus and are being treated in hospital.
In some areas, schools and offices have been shut.
What is the Nipah virus?
The Nipah virus was first identified in 1998 during an outbreak of illness among pig farmers in Malaysia, which killed more than 100 people and infected nearly 300.
Since then, it has spread thousands of miles.
The World Health Organization (WHO) says the fatality rate is estimated at 40 per cent to 75 per cent. The WHO adds: “This rate can vary by outbreak depending on local capabilities for epidemiological surveillance and clinical management.”
More than 600 cases of Nipah virus human infections were reported between 1998 to 2015, according to data from the WHO.
In 2001 an outbreak in India and two more in Bangladesh killed 62 of the 91 people infected.
In 2018, an outbreak in Kerala claimed 21 lives, there were other outbreaks in the state in 2019 and 2021.
Kerala is now battling its fourth outbreak since 2018.
There are no vaccines to prevent or cure the virus, which spreads through contact with the body fluids of infected bats, pigs or people. It can also be transmitted through contaminated food.
Scientists suspect the Nipah virus has existed among flying foxes for millennia and fear a mutated, highly transmissible strain will emerge from bats, Reuters has reported.
An investigation published by Reuters in May identified parts of Kerala as among the places most at risk globally for outbreaks of bat viruses.
It said: “Deforestation and development bring humans ever closer into contact with once-remote breeding grounds for bats and the viruses they carry.”
It added that Kerala, a tropical state, has suffered “extensive tree loss and rapid urbanization in recent decades” which had “created ideal conditions for a virus like Nipah to emerge”.
Where have the cases been?
All the cases have been reported in Kozhikode in the state of Kerala.
One death took place earlier this month, while the other happened on 30 August.
On Wednesday authorities said that they had tested 706 people, including 153 health workers, for the virus.
They are awaiting the results which will help determine the spread of Nipah.
What are the symptoms?
Reported initial symptoms may include:
- Muscle pain
- Sore throat
According to the BBC, in some people this could be followed by:
- Dizziness/and or drowsiness
- And/or altered consciousness
- And/or encephalitis
- And/or atypical pneumonia
- And/or other severe respiratory problems
What have government officials said?
People have been asked to avoid public gatherings in Kozhikode. They have also been asked to wear face masks and only visit the hospital in an emergency.
According to the BBC the state’s chief minister, Pinarayi Vijayan, has asked people to avoid public gatherings in Kozhikode for the next 10 days.
On Wednesday, the state’s Health Minister Veena George said tests had shown that the virus strain in the current outbreak was the same as the one found in Bangladesh in 2001.
Additional reporting by agencies