How a bat virus found new ways to infect people
STORY: India’s tropical state of Kerala has a message for residents: avoid eating fruit clawed or bitten by bats.
The warning is meant to prevent further outbreaks of the deadly Nipah virus, which is finding new and worrying pathways from bats directly to humans, as rapid urbanization encroaches ever further into once-remote breeding grounds.
In 2018, the Nipah virus killed Muthalib’s family members, including his father and two brothers.
His older brother Sabith was rushed to hospital first with fever, vomiting, delirium, tremors and violent coughing.
It took nearly two weeks after his death for doctors to realize what had killed him.
By then, another 22 people had become infected with Nipah virus. Only two of them survived.
But how did Sabith, the first to get sick, come down with Nipah?
A search of his family’s neighborhood led to a colony of flying foxes, a common fruit bat.
Some of the bats tested positive for Nipah.
(Muthalib) "We had many guava trees at home, as my father used to grow different varieties of them.So we had many varieties of guavas in our land itself. We used to have those fruits when they fell down. It is a common thing in our area that we have fruits like mango and all. We don’t eat mangoes if they have bite marks, but guavas, we eat after removing that part."
Fruits are just one theory offered by scientists of how Sabith became infected.
Nipah can infect people when they come into contact with fluids containing the virus: saliva, urine, blood and nasal or respiratory droplets.
There is no vaccine to prevent infection, and no known cure.
It’s considered one of the most dangerous pathogens circulating in the wild and is on the World Health Organization's short list of pathogens with epidemic potential.
(Veena George, Kerala Minister for Health and Family Welfare)
"The fatality rate with Nipah is very high, it is from 70-100%. And the mortality, the fatality rate of Nipah virus is much higher than COVID.”
The 2018 outbreak underscored the fast and aggressive path the pathogen can take.
Reuters analyzed conditions that make outbreaks like this one possible and found that by the time Sabith fell ill, this corner of India had become one of the likeliest places on Earth for a spillover to humans from bats.
We’ve dubbed places like this ‘jump zones’.
Reuters identified more than 9 million square kilometers in 113 countries where human alteration of bat habitats has created conditions that closely match those around past spillovers.
Kerala has some of the world’s riskiest jump zones.
It’s home to more than 40 species of bats and 35 million people.
Its forests, prime bat habitat, have been progressively cleared to make way for farming and development, creating ideal conditions for a virus like Nipah to emerge and infect people, often with lethal consequences.
And compared with prior known spillovers elsewhere in Asia, the outbreaks here have been particularly deadly, killing 90% of those infected.
Residents like Gokul Krishna say bats have become increasingly difficult to avoid.
Gokul says he cannot leave home without encountering them.
He caught and survived Nipah, but suffered memory loss and depression, long-lasting neurological problems shared by other Nipah survivors.
(Gokul Krishna, Nipah virus survivor)
"Yes. The big bats used to come to our courtyard. I had seen bite marks on the mangoes that fell down. Sometimes I would take those mangoes and throw them away to clean the pathway and leave my hands unwashed.”
India’s national government didn’t respond to Reuters phone queries or emails.
The press secretary for Kerala’s Chief Minister Pinarayi Vijayan emailed Reuters a statement citing the state’s efforts to mitigate spillover risk. The statement noted mapping of ecologically vulnerable areas and an initiative by two Indian universities to improve surveillance of animals and people for Nipah and other zoonotic viruses.
In Bangladesh – doctors pound the pavements with Nipah warnings.
Here though a different message: don’t drink raw date palm sap.
In early 2023, 7-year-old Soad Hossain died of Nipah…after drinking sap from a tree in his yard.
(Afroza Begum, Soad’s mother) “Doctors say he was attacked by the Nipah virus, and this is all we heard. My son is gone.”
Until people began getting sick from Nipah in Bangladesh, scientists had only seen the virus jump from bats to humans by way of an intermediary animal. It passed through pigs to infect people in a Malaysian outbreak.
Now, studies show that through the sap, the virus can infect people directly.
Despite warnings by public health officials to avoid drinking raw date palm sap, more than 160 have died since scientists discovered the connection in 2005.
Officials say some Bangladeshis, especially those who are illiterate, remain hard to reach despite the government’s public awareness campaigns.
(Mohammad Sanwar Hossain, Soad's father) “My son died. We will never get him back now. My advice to the others is that no one should drink date juice, especially not children.”