Editorial: Return of Nipah virus

Outbreak of the fatal virus is a wake-up call for authorities on the need to improve disease surveillance

At a time when the country is still grappling with the devastating impact of the Covid pandemic, the outbreak of the Nipah virus in Kerala is causing a major concern. It highlights the lurking biological threats. At least six cases of infection with the deadly virus have been reported in the State so far, bringing back the Covid-era curbs. The return of the fatal virus is a wake-up call for health authorities on the need to improve disease surveillance. Since May 2018, when Kerala reported the first Nipah case in Kozhikode district, there have been three more such outbreaks, including the latest one. Kozhikode, once again the epicentre of the infections, has been cordoned off as a containment zone. Businesses, schools and public places have been shut, and the only people visible are health workers in personal protective equipment (PPE) suits in a stark reminder of the year 2020. What is more alarming is that the disease has a high fatality rate of 45% to 70% and there is no known treatment or vaccine available. Nipah is a zoonotic virus that can be transmitted to humans from animals such as fruit bats and pigs. When the virus was first detected in 1999, the outbreak was believed to have originated in bats, which passed the pathogen on to pigs, which then infected pig farmers. The fruit bat is known to be the reservoir for the virus and at least two other species, pigs and humans, are susceptible to it.

Such zoonosis is what has worried infectious disease specialists for decades. The fear is that similar evolutionary strides can lead to another Covid-19 or, worse, a virus with Covid-19’s pandemic-grade infectiousness and the 25-90% fatality rate of Ebola, another zoonotic virus. There are urgent steps that need to be taken jointly by the Centre and State governments, including contact tracing, quarantine, isolation, collection and transportation of samples for lab testing, and a detailed study of the surrounding areas by the National Centre for Disease Control (NSDC) from an epidemiological standpoint. Nipah’s later-stage symptoms resemble Japanese Encephalitis, another viral disease that involves the fatal swelling of the brain. Both these traits make it hard for disease surveillance mechanisms to detect signs in time. Having learnt lessons from the past experience in handling the outbreak, Kerala has moved in quickly and identified from the first couple of patients — including the index patient who died on August 30 — that this was a Nipah outbreak. Since then, it has identified close to 1,000 people who may have caught the disease or passed it on. Swift identification and contact tracing can make the difference between nipping an outbreak in the bud or letting it snowball to epidemic proportions. Though Nipah is a deadly pathogen, there has been little progress on test kits, therapeutics and vaccines for it.