The Nipah virus is lethal, killing nearly 75% of the people it infects, but the circumstances under which bats, known as the Indian flying fox, transmit the virus to humans are still a mystery.
Now, a six-year multidisciplinary study has revealed how the Nipah virus, which took the lives of 17 people in Kerala in 2018, spread among fruit bats – the findings could help predict when pathogens could infect humans.
According to research published recently in the journal PNAS, Nipah virus (NiV) can circulate among fruit bats, not only in places where there have been outbreaks of human disease but also in any areas where they exist.
Lead author of the study, Jonathan Epstein from EcoHealth Alliance in the US, told PTI: “To prevent human outbreaks, we need to know when bats can transmit the virus and this research provides insight. about Nipah infection patterns in bats.
While previous studies from Kerala and parts of Bangladesh have shown that Indian flying foxes can transmit the virus, Epstein says there is “the theoretical possibility of infecting humans any time of the year, any time of year. wherever this bat and person come into contact.
However, it̵7;s crucial to have these bats around as they are essential to pollinate fruit tree seeds, says Epstein, who belongs to the group that identifies horseshoe bats as animal hosts of the pandemic virus. Said SARS 2002-03.
“So it is not about eliminating them, therefore, it is more important to understand the pathways of virus transmission, and to know when they contaminate our food and water,” he explained.
According to the disease ecologist, it is important to extend bat species surveillance for viruses to other parts of India.
These bats are well adapted to living with humans, and are common across the Indian subcontinent, “stretching to Nepal”.
“In the villages, we see hundreds to thousands of these bats perched on hardwood trees. The size and density of these flocks is important,” says Epstein.
He warned that chasing the bat away wouldn’t solve the problem as it would only redistribute them to other plants, creating denser colonies.
As long as 60 to 70 percent of the bats in the population have antibodies that protect against the virus, there is no possibility of an outbreak, the scientists said.
“What this study shows for the first time is that, over time, bats in nature lose the antibodies that protect them from NiV reinfection,” says Epstein.
When a large enough proportion of the bats are immune to the virus, there won’t be much transmission, but when the ratio drops below the threshold, the entire herd becomes susceptible, he said.
When that goes down, sometimes down to 20%, the population is like a pile of dry wood and as soon as someone throws a match – that is, when NiV is put in by an infected bat – you will Epstein explain.
Scientists say bats outbreaks in Bangladesh appear to occur every two years, adding that it is important to understand this cyclicality.
When there is an outbreak among bats, “the largest number of them” will shed the virus in their feces, urine and other body fluids, and give NiV a chance to jump to humans, Epstein said.
Studies have shown that the virus can be transmitted to humans through date packaging or infected fruit from infected bats.
“During an earlier outbreak in Malaysia, pigs amplified the virus,” says Epstein. They are infected and produce more viruses than bats.
Researchers say people can be protected from exposure to the virus by “simply preventing contaminated dates or by not eating fruit that has a bat bite and making sure that the fruit. do not feed the animals “
“Fortunately, the Indian Government has started to pay attention since the Kerala outbreak, and is also conducting an investigation of the bat,” added Epstein.
“It is important to determine the spectrum of NiV strains circulating in India and South Asia, know if there are more virulent strains and make a general prediction of when the bat will be on the outbreak,” Epstein said. Epstein said.
He added that even if NiV outbreaks in fruit bats in India could follow a similar cycle pattern, the cycle could be different.
Commenting on the study, virologist Upasana Ray, who was not involved with the research team, said the findings underscore the importance of animal pathogen surveillance to predict the likelihood that they will spread. people.
Ray, a senior scientist at CSIR-IICB, Kolkata, told PTI: “NiV is one of many bat-transmitted viruses and is included in the headlines every year, or every year in countries including India.
She believes identifying such viruses and developing treatment strategies early can help reduce their impact on people’s lives.
“The Nipah virus continues to jump from bat to person and we can’t wait for another pandemic to take action,” says Epstein.
“Those actions don’t mean killing bats, but protecting our food from bat feces,” he added.