A recent outbreak of Nipah virus encephalitis in India, an often fatal viral disease without cure, has raised international alarms regarding the virus's potential to become the next threat to global health.
Nipah outbreaks begin with the spread of the virus from its natural reservoir ̵
The virus causes severe brain swelling called encephalitis and in some cases respiratory disease, and usually kills three quarters of infected people. So far, the virus has not spread so easily from human to human, said veterinarian and epidemiologist Jonathan Epstein, V02, MPH02, since 2003 on ecology and epidemiology of the Nipah virus.
But with every spill of the Nipah virus from bats to humans, there are fears that a strain that could more easily be transmitted among humans could arise, said Epstein, vice president of science and public relations at EcoHealth Alliance, the adjunct faculty Appointments to the Tufts School of Medicine and Cummings School. Epstein talked to Tufts Now about the origins of the Nipah virus, which is why the World Health Organization has declared it one of the top ten priority pathogens and what we've learned so far about the outbreak in India where Nipah had killed at least fourteen people on the 30th. May.
Tufts Now: The Nipah virus is as deadly as Ebola, right?
Jonathan Epstein: Yes, it is comparable. Each outbreak has its own mortality rate, and outbreaks can vary greatly depending on how easily they spread among humans and how deadly they are, depending on who gets infected and what genetic strains the virus itself has. But in general, Nipah tends to have an average mortality rate of 75 percent – and some outbreaks were 100 percent deadly. From this perspective, Ebola has had similar mortality rates.
Do we know what caused this outbreak?
We do not know exactly, as there is still no good information about the original human cases were infected. In Bangladesh, there were fifteen recognized Nipah virus outbreaks – it occurs almost every year, such as a seasonal disease – and this is the third Nipah outbreak in India since 2001. The first known Nipah outbreak was in 1998 at a pig farm in Malaysia, the inspired the plot for the movie "Contagion" 2011.
In most previous outbreaks in Bangladesh and India, the virus's first spill over contaminated food, typically date-palm juice. To collect the juice, people shave the bark off palm trees so that it falls into a collection pot. The juice is then eaten either fresh as a sweet drink – a delicacy similar to sugarcane juice – or fermented. Humans can become infected with the Nipah virus when bats come at night to lick the trunks of the trees while the juice is flowing, and when they drink a sugary drink, they contaminate the juice or underlying pot with saliva or urine, who carries the virus] Is there anything that particularly concerns this outbreak?
Fortunately, the outbreaks of Nipah disease were self-limiting because the virus does not spread very easily from human to human. Outbreaks tend to fizzle out after four or five chains of transmission in humans.
But our concern every time there is a new outbreak is that a genetic burden will arise from Nipah that spreads efficiently among humans so that we could have another situation like Ebola in West Africa, which is more than Killed 11,000 people. And with Nipah we just do not know if this version is already lurking in nature.
Is there any danger of Nipah traveling outside of India?
Yes, theoretically it is possible that if Nipah Falls are heading to a city where there is an international airport, someone who is infected with Nipah could get on a plane and go to another country. That's why it's important to keep an eye on all the cases we know about now, and the people they've come in contact with, and restrict their travel and make sure they're treated in a hospital. The outbreak in Kerala is not far from an international airport in Mangalore, but the outbreak seems to be well contained by the Indian health authorities, so a broader spread seems unlikely at this time.
Why is Ebola so much better known than Nipah?
Many people have heard of Ebola for several reasons. For beginners, Ebola has been known since 1976; Nipah virus was discovered about twenty years later. Ebola also made headlines at the end of 2014, when people infected with Ebola moved from West Africa, the site of the deadliest Ebola outbreak in history, to the United States and countries in Europe.
Ebola is also a very dramatic and frightening disease that – in addition to killing many people like Nipah – has the rather alarming symptom of heavy bleeding. Nipah occurs in parts of the world where other diseases that cause less deadly brain swelling are common – and it can be associated with these and other typically less lethal diseases for similar early flu-like symptoms such as fever, headache, muscle aches and vomiting and sore throats
Is there any positive news about the reaction to the current Nipah outbreak?
The good news is that the Government of India has the ability to deal with Nipah. The Indian Institute of Virology in Pune has conducted research and research on the virus in the past, and India has a good public health infrastructure. A nationwide investigation into this outbreak was swiftly launched and the country has the resources to curb it. Although there is currently no approved vaccine or treatment for Nipah, India has turned to Australia to try an experimental therapeutic in development that hopefully will reduce the severity of symptoms and prevent mortality
Although there are hundreds of species of bats, the research primarily involves huge fruit bats that travel a long distance to feed at night, up to fifty kilometers – 31 miles from their sleeping place. This means you will not have to find giant fruit bats that are where people first became infected. They could have fled ten kilometers-six miles-to eat some fruit or drink juice the night someone got infected. For this reason, an adequate wildlife experimentation requires an understanding of bat ecology and behavior. it's not just about grabbing the closest bats to the house of the infected person. Will there be a fight in India?
We do not hope. I am encouraged to see many Indian news stories that remind readers that bats are not to blame and are ecologically important. I think we must continue to emphasize that spillover events like these are fortunately quite rare. And although there are plenty of bats that carry Nipah, evidence suggests that the virus is rarely found even in these bats.
People also need to remember that humans are responsible for the pathway of disease transmission. by cultivating food resources that bats and other wildlife have learned to use. Date palm juice is the perfect example. If humans did not scrape off the bark from trees, bats would never have access to the sweet liquid flowing in it. So, to be protected from diseases like Nipah, we do not need to get rid of bats, but understand our intertwined relationships so we can make our food safer.
Nipah claims another victim in India, the death toll is now 13