Opinion Express View: Checking Nipah

The Nipah virus has surfaced in Kerala for the fourth time in the past five years. Two people in Kozhikode district have succumbed after being infected by the pathogen. The district authorities have shut down educational institutions and cordoned off seven villages as containment zones. Neighbouring states have been put on alert. Kerala had used these measures with a fair degree of success during the past Nipah outbreaks. Even then, it needs to be vigilant against the virus, which, though not as infectious as influenza or Covid, can turn lethal very fast. In severe cases, patients develop respiratory distress and brain fever and the case fatality rate can be as high as 75 per cent. There is no vaccine against the pathogen and treatment, even in hospital settings, is limited to targeting the symptoms.

The Nipah virus was first identified during an epidemic that affected pig farmers in Malaysia and Singapore in 1999. Two years later, the pathogen claimed more than 40 lives in West Bengal. ICMR surveys have shown that the virus has a natural reservoir in fruit bats. One plausible theory is that it spreads after contact with secretions containing the virus on trees, fruits, date palm sap, juice or toddy. The infection can spread from human to human through close contact at home or in hospitals. Though the risk of super spreader events is currently low, experts caution against complacency. Each outbreak creates possibilities of the virus mutating and brings with it the risks of the emergence of a strain that transmits more efficiently. That’s why the WHO has classified Nipah as a virus of concern.

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Efforts are on to develop antidotes to the disease in several parts of the world, including India. The WHO also suggests that countries with Nipah hotspots develop strategies to anticipate, monitor and control outbreaks. It is important, for instance, to understand what is happening in the virus’s animal reservoir before it spills over to humans. Experts believe that checking zoonotic diseases, Nipah for example, will require cross-disciplinary collaborations between professionals in human, animal and environmental health. To understand Nipah, it is important to identify patterns of the virus’s circulation in fruit bats and document the spillover events between species. Studies show that though most fruit bats carry Nipah, only a minuscule number of them release the pathogen into the environment. But we do not know why and when they do so. There is much to be done in understanding the virus. The world’s experience with Covid should be a warning that the task shouldn’t be postponed for long.