Short Wave - A Fatal Virus With Pandemic Potential

Episode Date: February 2, 2023

The Nipah virus is on the World Health Organization's short list of diseases that have pandemic potential and therefore pose the greatest public health risk. With a fatality rate at about 70%, it is one of the most deadly respiratory diseases health officials have ever seen. But as regular outbreaks began in the early 2000s in Bangladesh, researchers were left scratching their heads. Initially, the cause of the outbreaks was unknown to them. But once they identified the virus, a second, urgent question arose: How was the virus jumping from bats into humans?This episode is part of the series, Hidden Viruses: How Pandemics Really Begin.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Three years ago, the World Health Organization alerted the world that a major health crisis was brewing. It declared COVID-19 a public health emergency of international concern. And as we know now, that emergency became one of the world's deadliest pandemics in history. And to keep this from happening again, scientists all over the world have been studying how to detect and stop viruses with pandemic potential. And so we invited R.A. Daniel, one of NPR. PR's Global Health and Development Correspondence on today. He's been looking into this, specifically on a recent trip to Bangladesh.

So, Ari, it sounds like we can start with some good news. Researchers are making some progress, right? That's right, Regina. Just take the virus called NEPA. It's on the WHO's short list of diseases that could go global. So back in December, I visited a local family that got hit by that outbreak in 2004. A 50-year-old man named Kokan was sitting outside his home beside a rice paddy. Think Zeus, but more casual.

A fiery beer dyed a bright orange ringed his chin. And when I talked to him, he said he'll never forget that spring. So the first one was the mother-in-lawful hospital. So the mother-in-lawed-law. So the first one was the mother-in-law. of my elder brother. She was really sick. She had been sick for some time.

Then she died. We took her to the grave. Then my father got sick. And his father was a spiritual leader in the community. When he became ill, many came to pay their respects, offer prayers. Just 12 days after my father died.

Suddenly, he was no more. Many of those visitors also got sick. One traveled to an adjacent village where four more people fell ill. Wow. So what does that illness from NEPA look like? Well, at the time they didn't know. Mahmouda Rahman is the former director of the Institute of Epidemiology, Disease Control, and Research for the Bangladeshi government. He says in those days,

Some people who were transporting the patients to the hospital were also getting sick. Sick often meant encephalitis. So like swelling of the brain. rain. Exactly. Epidemiologist Emily Gurley, now based at Johns Hopkins University, was leading an on-site investigation at the time, and she says that swelling led to lots of other issues. The signs and symptoms of encephalitis are fever, headache, but often altered mental status, or coma, seizures. But many of these patients also had respiratory disease. Then Kokin and his wife, Unwara, fell ill. It's why I'm only using their first names.

because the disease carries stigma. The couple went unconscious, and they have no memories of their tangle with Nipa. people couldn't say, if we were dead or alive, they said that we had to be able to. They said that we had high fever, very high fever, like whenever, they were touching us. It was like touching fire. And NEPA has kept on resurfacing in different locations across Bangladesh almost every year since. But, and this is a big butt, researchers have since figured out a way to stop the virus.

But it's complicated. Today on the show, a virus with pandemic potential and how scientists figured out how it got from animals into people following a map drawn in the dirt of a local village. I'm Regina Barber. You're listening to Shortwave, the Daily Science podcast from NPR. So, Ari, it sounds like Nipa is an ongoing concern in Begledish, but what happened to Kukun and his wife? Miraculously, they both survived, but the rest of their close-knit family did not. Kukun's older brother, his sister, two uncles, his aunt, his nephew, and his mom and dad, all dead. It was numbing. This outbreak, Mahmouda says, made something brutal.

evident. This is obviously showing that we are unable to control it and it is spreading. But they still didn't know what the illness was that was sweeping through the area, right? Not at the time, no. Did it have a big death rate? Like 70%. Oh my gosh, that's huge. Yes, and so they were all scratching their heads, like what virus could be that lethal? We didn't know. I was just looking at the data. I was just looking at data to see what do we think is going on here. A few weeks later, Emily and our colleagues got an email from the CDC in Atlanta that this was the NEPA virus. Okay, so I got to admit, before you're reporting, I had never heard of NEPA. When and where was it for a scene? Well, back in the 90s in Malaysia, when it first

emerged, NEPA was spreading from local fruit bats to pigs to pig farmers. But in Bangladesh, the virus was behaving differently. It was being transmitted person to person, which had never been reported before. So that was a scary time. Without the pigs as intermediaries in Bangladesh, just how was NEPA spilling over from bats into humans in the first place? Yeah, that's the $20 million question, right? To shut this thing down and prevent future outbreaks. Exactly. And it was tricky because these outbreaks, each one tragic, they fizzled pretty fast. But each time the virus leaps from bats into people, it gets another opportunity to mutate, possibly becoming more transmissible. The fear being, Regina, that the right combination of mutations could propel it into the realm

of a deadly pandemic. So what we did is walk through the village and thought about all the possible ways people could come into contact with bats or bat secretions, bat urine, bat saliva. Finding this link, it's agonizing. slow work. And so it wasn't until 2007, a few years later, that the researchers got a break with the help of Rebecca Sultanah, an anthropologist who joined the investigation team. She's with the International Center for Diareal Disease Research Bangladesh, or ICDDRB for short. After spending some time in the village, she asked the community to meet her in the town market to help her draw a map of the village. I don't do anything. I just ask question and then they draw it.

They draw it. Yeah, they draw it. Using sticks in the dirt, the residents roughed out houses, roads, bat roosts, and then they began sketching in date palm trees. Oh, okay, I see where this is going, bat and human food. Yes, exactly. The date palm trees produce a sweet sap that both the bats and people like to drink. And we thought, well, this would be a great way to have contact with bats secretions

because I'm sure the bats love the sap, and so do people. So Rebecca and her colleagues tracked down the sap harvester, and he led them to a few pals of the guy who was patient zero. They said we all used to drink raw sap in the morning. So it sounds like she kind of had an aha moment with the sap. Yes, the line between the bats, the sap, and the outbreaks was becoming clear. Over the next few years, researchers took infrared cameras and caught the bats at night drinking from,

and sometimes peeing into the same stream of sap that people were harvesting. Eventually, the government had enough evidence to launch a campaign against the drinking of raw sap. Some heard that message, but many people have continued to drink the sap. And the spillovers of NEPA virus from bats to people have continued too. So people are still drinking raw sap. Is there anything else that can be done? As a matter of fact, yes. So I was in Bangladesh back on December 1st.

That's the beginning of what's known around there, notoriously, as NEPA season. The four months when the virus is most likely to show up. This is when the sap is harvested and by some consumed raw. Every month, Ashrafal Islam, a veterinarian and infectious disease specialist at the ICDDRB, he brings a team out here near 4Aipur to capture greater Indian fruit bats. He's looking for another way to stop NEPA. Are they capturing the bats to get rid of them? No, not at all.

Usherful actually has enormous respect for them and their importance to the local ecosystem. He's interested in collecting them because here's the thing. Even though so many of them harbored the virus, fewer than 1% of them actually release it into the environment through their urine or saliva. Really? Why do so few of them shed the virus? Well, Ashrifl thinks it's most likely connected to stress.

Is it lack of food? Is it pregnancy stress? Is it lack of habitat? Knowing what's behind the shedding could help Osirful and his colleagues figure out how to keep NEPA from infecting people in the first place. What just happened? We are able to catch our bats. So a bat just flew into the net.

The bat was big. An adult's wingspan can easily reach like three feet. If it gets the chance, it will bite you like 10, 15 times. They're very bitey. They've just untangled it. I hope they're putting it in the bag. The team nabbed one more bat, and then they called it quits. It was getting too light.

They put the bats into a three-wheeler and ferried them to a local lab, an unassuming one-room building down an ordinary lane. And yet, this little place is a crucial outpost in the battle against NEPA. It's where the researchers took blood and... urine samples from the bats, and once they were done, they released the animals back into the woods. It was on the drive to the lab when Ashrafal made a pit stop in a village to show me the date palm trees, the boiling molasses. It is possible that they will offer you a glass of sap. Please gently deny it, okay? Thank you so much for this story, Ari. Of course, Regina. Thank you for

having me. This is the first story in a series called Hidden Viruses, how pandemics really begin. Check npr.org in the following weeks for more of the series. Today's episode was produced by Liz Metzger, edited by our supervising producer Rebecca Ramirez, and fact-checked by Anil Oza. This story was edited for radio broadcast by Rebecca Davis and Vicki Valentine. The engineer was Valentina Rodriguez-Sanchez. Brendan Crump is our podcast coordinator. Our senior director of programming is Beth Donovan, and the senior vice president of programming is Anya Grannman. I'm Regina Barber. Thanks for listening to Shortwave from NPR.