The Indian Council of Medical Research (ICMR) confirmed on 3 July that fruit bats were the primary source of the Nipah virus outbreak in Kerala's Kozhikode and Malappuram districts, where 17 people died due to the virus earlier in 2018.
Initially, a central medical team had ruled out bats as the primary source of the infection after the samples collected from bats in two Kerala districts tested negative.
Later, another medical team in its report to the Union health ministry said bats cannot be ruled out as the samples were collected from insectivorous bats, which are not known to be Nipah carriers.
In the second round, samples from 55 fruit bats were collected and sent to National Institute of Virology in Pune.
An ICMR official said the samples from fruit bats tested positive for the virus, confirming that they were the source of Nipah infection in Kozhikode and Malappuram districts.
What is Nipah Virus?
According to the World Health Organisation, Nipah virus or NiV infection is a newly emerging infectious disease that causes severe illness in both animals and humans.
The natural host of the Nipah virus are fruit bats of the Pteropodidae Family, Pteropus genus.
Nipah virus is fairly new. The virus was first identified in 1998 in Malaysia and pigs were identified as the intermediate host. It spread to humans after they came in contact with pig feces and excretions. Nipah virus gets it’s name from the village where the virus was first spotted. The virus has also been found in species of domestic animals including dogs, cats, goats, horses and sheep after they came in contact with pigs.
Why Has Nipah Virus Emerged?
Epidemiologists attribute the emergence of this type of virus to the loss of the natural habitat of bats.
According to the WHO fact sheet on the Nipah virus, this loss results in bats getting stressed and hungry, their immune system gets weaker, their virus load goes up and a lot of virus spills out in their urine and saliva.
The outbreak of Nipah virus was first reported in Kampung Sungai Nipah, Malaysia in 1998. There is no vaccine or drug to treat Nipah infection.
The primary treatment for human cases is intensive supportive care.
Symptoms of Nipah Virus
According to the World Health Organisation, human infections range from asymptomatic infection, acute respiratory infection (mild, severe), and fatal encephalitis. Infected people initially develop influenza-like symptoms of fever, headache, myalgia (muscle pain), vomiting and sore throat.
This can be followed by dizziness, drowsiness, altered consciousness, and neurological signs that indicate acute encephalitis. Some people can also experience acute respiratory distress.
Encephalitis and seizures occur in severe cases, progressing to coma within 24-48 hours.
(With inputs from PTI)
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