TOPSHOT - In this photograph taken on September 12, 2023, health workers wearing protective gear ... [+]
Anyone who watched the movie Contagion may remember the dramatic scene when Gwyneth Paltrow seized on her kitchen floor as the world battled a virus that causes severe encephalitis. The movie virus was inspired by the real-life Nipah virus, which causes a deadly infection of the brain. Nipah virus has no licensed treatment or vaccine, but that could finally change, according to a study recently published in the journal Science and Translational Medicine.
As reported in the study, scientists from multiple institutions, including the Uniformed Services University, University of Texas Medical Branch, Galveston and Mapp Biopharmaceuticals compared the effectiveness of two different monoclonal antibodies against Nipah virus. In order to infect and enter a cell, the virus has to first bind to the cell and then fuse with the cell membrane. A previously developed antibody (m102.4) against Hendra virus, a close “cousin” to Nipah that has caused deaths in horses and humans in Australia, targets the viral glycoprotein needed for binding. The m102.4 antibody was compared directly against a new antibody, hu1F5, which targets the fusion glycoprotein on the virus and blocks the virus’s ability to fuse and enter a cell.
In the study, two groups of six African green monkeys were infected with Nipah virus. Five days later, half of the monkeys received m102.4 and the other half received hu1F5. Only one monkey receiving m102.4 survived, whereas all six receiving hu1F5 survived. That’s a huge difference.
Where Did Nipah Virus Come From?
Nipah has caused deadly outbreaks in Malaysia, Singapore, the Philippines, India and Bangladesh. The most recent outbreak occurred in India in 2023, causing six confirmed cases and two deaths.
TOPSHOT - A bat flies between trees in Guwahati on May 23, 2018. A deadly virus carried by fruit ... [+]
Nipah represents a classic spillover problem where animals transmit pathogens to humans. Large fruit bats, commonly referred to as flying foxes, serve as the reservoir in nature. In the first outbreak in Malaysia in 1998, bats initially infected pigs, and then people who had contact with diseased pigs subsequently became ill. The disease was recognized when Malaysian pig farmers came down with severe and frequently fatal encephalitis. The outbreak led to over 265 cases of encephalitis and 105 deaths. It subsequently spread to Singapore, occurring in slaughterhouse workers.
The outbreak occurred due to an unfortunate convergence of ecological factors related to deforestation, causing the flying foxes to move into closer proximity to pigs, and therefore humans. The site of the initial outbreak served as both a pig farm and an orchard, making it an ideal location for roosting bats to cozy up to pigs. Climate change may also be aiding in the expansion of suitable areas for Nipah’s bat hosts.
In addition to human illness, the outbreak caused significant economic damage as a result of the slaughter of nearly 1 million pigs to control the outbreak.
Another strange convergence of ecological factors led to the emergence of Nipah virus in Bangladesh and India. During the process of collecting date palm sap with open vessels (similar to collecting maple syrup in the U.S.), bats roosted in the palm trees and contaminated the vessels with their urine or saliva. Subsequently, those who drank the raw palm sap became infected with Nipah. Some more frightening aspects of the outbreaks that occurred in central Asia included spread from person-to-person and higher fatality rates.
What Are The Clinical Features?
After infection with the virus, individuals become ill usually within two weeks. Typical symptoms in the Malaysian and Singaporean outbreaks included fever, headache, dizziness and vomiting, with over 50% developing diminished level of consciousness. Respiratory symptoms were an uncommon feature; however, in Bangladesh and India, respiratory symptoms were more common and may account for the increased person-to-person spread as well as transmission to healthcare workers.
Do You Need To Worry?
We have learned the hard way with multiple infectious diseases, including influenza, Covid-19 and Ebola virus, that diseases don’t respect international borders. The fruit bats that can carry Nipah have an extensive range, from Pakistan to Australia. There is the possibility that a traveler visiting the areas where the bats live could become infected and bring the disease back home. This is just one of the many reasons to avoid animals while traveling.
What Is The Impact Of This Study?
The results of the study provide promise for potential future testing of the hu1F5 monoclonal antibody in humans. Given that Nipah continues to surprise us with periodic outbreaks, it would be great to have such a potential new countermeasure expand our armamentarium, because we’ll need it when the next Nipah outbreak occurs. It’s a matter of when, not if.
