According to WHO, the Nipah virus infection is a newly emerging zoonosis, that is, a disease transmitted from animals to humans. The virus belongs to a new genus termed Henipavirus (subfamily Paramyxovirinae).
Which animals can spread the disease?
The natural host of the virus are fruit bats belonging to the family Pteropodidae. In 2004, humans were affected after eating the date palm contaminated by infected fruit bats. Pigs can also act as intermediate hosts.
When was it first reported?
It was first identified in 1998 in a village of Malaysia. The virus is named after this village.
What are the symptoms in humans?
The symptoms of Nipah are similar to that of influenza: fever, muscle pain, and respiratory problems. Inflammation of the brain can also cause disorientation. Late onset of Encephalitis can also occur. Sometimes a person can have an asymptomatic infection, and be a carrier of Nipah and not show any symptoms.
Are there any vaccines?
Currently, there are no vaccines for both humans and animals. Intensive supportive care is given to humans infected by Nipah virus.
Who were affected in India?
In 2018, infection with the Nipah virus has killed at least 10 people out of 12 confirmed cases in Kerala. While underlining the dangers of the disease, which has a high mortality rate, experts stress that there is no reason to panic because outbreaks, usually caused by fruit bats, have been generally localised.
The reservoir for the virus is fruit bats, which live on trees and rarely come into contact with humans. Bats can infect pigs, too, another way the disease can spread to humans. Infected humans can spread it to others they come in contact with.
Containment vs treatment
Timely laboratory confirmation and aggressive tracing of contacts with patients and isolation can contain spread of the virus. This is important because there is no effective specific treatment for the infection. Treatment is symptomatic and supportive. Severely ill individuals need to be hospitalised and may require intensive care. Because Nipah virus encephalitis can be transmitted person-to-person, standard infection control practices and proper barrier nursing techniques are important.
The disease has a very high mortality rate, which is the reason for the rush to contain it. In the previous two outbreaks in India, both in West Bengal, there were 42 deaths out of 72 cases in Siliguri in 2001, and five deaths out of 30 who showed the symptoms in Nadia in 2007.
The virus leads to rapidly progressive encephalitis with or without respiratory involvement. Nipah encephalitis occurs with fever and headache, followed by drowsiness, disorientation and mental confusion. Acute encephalitis may progress to coma. Symptoms include cough during the early part of the disease.