Nipah virus outbreak in India: the escalating threat of zoonotic diseases
India is currently grappling with a rare Nipah virus outbreak, a zoonotic disease with a high mortality rate. The Nipah virus was first identified in 1998 amongst pig farmers in Malaysia, with the name originating from the village where it was first detected. Though occurrences are infrequent, the World Health Organization (WHO) has categorised Nipah alongside Ebola, Zika, and Covid-19, as a disease requiring priority research due to its potential to incite a worldwide epidemic.
The virus typically transmits from animals to humans, usually through contaminated food, but there is also a possibility of human-to-human transmission. Fruit bats have been pinpointed as the primary carriers of the virus, which commonly causes symptoms such as severe fever, vomiting, and respiratory infection. More serious cases can escalate into seizures and brain inflammation, often leading to a coma. Presently, there is no known vaccine for the Nipah virus, and the mortality rate lies between 40% and 75%, depending on the effectiveness of the public health response, according to the WHO.
In past outbreaks, the Nipah virus has proven to be devastating. The initial outbreak in Malaysia resulted in over 100 fatalities and led to the slaughter of one million pigs to curb the virus spread. The disease also extended to Singapore, causing 11 cases and one death amongst slaughterhouse workers who had been in contact with pigs imported from Malaysia. Since then, the majority of Nipah cases have been reported in Bangladesh and India, both of which experienced their first outbreaks in 2001.
Bangladesh has suffered most in the recent past, with over 100 Nipah-related deaths since 2001. Two initial outbreaks in India resulted in more than 50 deaths before they were successfully contained. Kerala, a southern state in India, has reported two deaths and four confirmed cases of Nipah since last month. In response, authorities have closed several schools and initiated mass testing.
This is the fourth recorded Nipah incidence in Kerala within the past five years. The first occurrence in 2018 resulted in 17 deaths. However, the state has managed to swiftly contain past outbreaks within weeks through extensive testing and stringent isolation of those in contact with infected patients.
Zoonoses, diseases transferable from animals to humans, have increased in frequency over the past 20 to 30 years, despite first appearing thousands of years ago. The surge in international travel has facilitated their spread.