In India, the Nipah virus resurfaces and kills two people in Kerala

Indian authorities launched a virological testing campaign on Thursday September 14 to stop the spread of the Nipah virus, a deadly disease already causing two deaths in the state of Kerala, in the south of India. At least four people were hospitalized, including the child of one of the victims. More than 700 people, including 153 medical sector employees, are under observation after being in contact with infected people, health authorities said.

“We are working to quickly trace the contacts of infected people and isolate anyone with symptoms,” said Veena George, state health minister, who also indicated that the strain of the virus was in progress. review, according to Reuters. Since 2018, this is the fourth time that an epidemic of the Nipah virus has appeared in the country.

Rare, certainly, but deadly, this virus can cause fever, vomiting and severe respiratory and neurological complications: serious cases can lead to epileptic seizures and encephalitis, which can go so far as to cause a coma. The mortality rate from the virus is between 40 and 75%, according to the World Health Organization (WHO). Faced with this new epidemic, the authorities announced the supervision of public gatherings and the closure of certain schools.

Nipah is a type of Henipavirus, related to the Hendra virus, first discovered in Australia when it caused the deaths of humans and horses. The Nipah virus can infect humans directly through contact with the bodily fluids of bats, specifically their saliva and urine. Some cases of transmission between humans have also been recorded, or through contaminated pigs.

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“It is carried by fruit bats that live at the tops of trees,” Joanne Macdonald, associate professor of molecular engineering at the University of the Sunshine Coast, told the British newspaper The Guardian. “Bats contaminate fruit through their urine: when people eat these fruits, they catch the virus and get sick.”

Epidemics are rare, but Nipah has been listed by the WHO as a priority disease for research due to its global epidemic potential, placing it in the same category as Ebola, Zika and Covid-19. In addition to its epidemic potential, Nipah is considered a high-risk disease by the WHO due to the lack of vaccine or treatment.

The first outbreak of Nipah was detected in 1998. Starting from the village of Nipah, which later gave its name to the disease, the virus then spread among pig farmers in Malaysia and Singapore. This first epidemic infected nearly 300 people in Malaysia, and caused the death of around a hundred others. In order to contain the epidemic, a million pigs were slaughtered. The virus also spread to Singapore, where 11 cases and one death were recorded: slaughterhouse workers who had been in contact with pigs imported from Malaysia. Since then, the disease has mainly been recorded in Bangladesh and India, both countries having reported their first outbreaks in 2001. In India, the first two epidemics caused the death of 50 people, while Bangladesh has suffered more from the virus in recent years, with more than 100 people who have died since 2001. According to the WHO, 600 cases were recorded between 1998 and 2015.

In the last five years, India has faced four epidemics of the virus: in 2018, in 2019, in 2021, and a new one since last month in the state of Kerala, which has already caused two deaths. In 2018, at least 17 people died after being infected with the virus, also in the state of Kerala.

There is no known vaccine or treatment for this virus, which explains the fear it generates despite its relatively rare occurrences. “Once the disease is contracted, the only treatments are rest, hydration and treatment of the symptoms,” emphasizes Joanne Macdonald.

While the incubation period generally varies between about four and 14 days, it can be up to 45 days. In 2019, a study by the Institut Pasteur, the CNRS and the John Hopkins Bloomberg School of Public Health carried out on more than 2,000 cases of the Nipah virus in Bangladesh demonstrated that adult cases presenting respiratory symptoms infected more individuals than others.

During previous epidemics, the Indian authorities managed to stop contamination in a few weeks, by setting up widespread testing campaigns and strictly isolating contact cases.

Zoonoses, diseases transmissible from animals to humans, have increased in recent decades. For many scientists, this is explained by industrial agriculture and deforestation, in particular because these phenomena cause more contact between wild animals, domestic animals and humans. Global warming is also responsible for changes in the ecosystem of certain species. Finally, the increase in travel around the world has also enabled this rapid evolution of zoonoses. Scientists have warned that the climate crisis is increasing the risk of “zoonotic spillovers”. They predict that 15,000 cases of the virus will be transmitted between species over the next 50 years, according to The Guardian.