Bat-borne Nipah Virus Could Become New Scourge in India

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Bat-borne Nipah Virus Could Become New Scourge in India
Bat-borne Nipah Virus Could Become New Scourge in India

Indian health authorities are sounding the alarm after dozens of people have become infected and a 12-year-old boy died from the Nipah virus, for which there is currently no vaccine. So what do we know about the outbreak?

A team of specialists was sent to the southern state of Kerala to assist local doctors after samples taken from a deceased child tested positive for the Nipah virus. Before he passed away on Sunday, the boy had symptoms of inflammation of the brain and heart muscle - conditions known as encephalitis and myocarditis.

To date, 11 people have been diagnosed with a rare zoonotic virus in Kerala. Among them are the boy's parents, his relatives and some doctors who treated him. More than 250 more people have been identified through contact tracing, 54 of whom are at high risk and are required to self-isolate.

How dangerous is the Nipah virus?

The World Health Organization (WHO) estimates that mortality rates range from 40% to 75%, depending on the effectiveness of the health system in the affected region. In contrast, the death rate for Covid-19 is between 1% and 2%, according to global data, although it is more contagious.

Nipah causes an acute respiratory infection with fever, headache, muscle pain, vomiting, and sore throat. In severe cases, encephalitis develops, which can lead to coma and death. The absence of specific symptoms in the early stages makes it difficult to detect nipach, which often leads to delays in implementing control measures and, consequently, to even more infections.

Where did he come from?

The virus gets its name from the Malaysian village of Nipah, where the first outbreak among pig breeders occurred in 1999. There have been no new cases in Malaysia since then, but outbreaks in Bangladesh have become an annual problem since 2001. Infections have also been detected periodically in India. The virus is thought to be hosted by fruit bats known as flying foxes, which form large treetop colonies throughout South and Southeast Asia, often close to human settlements.

How does it spread?

People usually contract the virus by eating fruit or drinking the raw juice of the bat tree, the date palm, that has been contaminated with the saliva or urine of sick flying foxes. Pigs, horses, goats, sheep, cats and dogs can also serve as intermediate hosts. Unlike Covid-19, which can be spread by airborne droplets, Nipah is transmitted from person to person through close contact, through secretions and secretions, so the relatives of the infected and the doctors caring for them are usually among the first to become infected. During the previous outbreak in Kerala in 2018, the Nipah R-number - an indicator of "reproduction" that shows how many people on average one sick person can infect - was 0.43, while the R-number of coronavirus is estimated at more than 1. An R number below 1 means that the infection will eventually die out.

What is the treatment?

The WHO has identified the Nipah virus as a priority disease for research and development, however, there are currently no drugs or vaccines specific for this virus. She recommends only intensive care therapy for those suffering from severe respiratory and neurological complications. Indian authorities ordered monoclonal antibody drugs from Australia that helped contain an outbreak in Kerala three years ago, and local doctors have also found the antiviral drug ribavirin to be effective in lowering viral load in patients with Nipah virus.