The Nipah virus is a zoonotic virus with a high mortality rate; it has recently struck again in southeast Asia, affecting Bangladesh and the southern Indian state of Kerala. Bangladesh has been home to seasonal outbreaks since 2001. The current episode has been the fourth in Kerala.
The Nipah virus is a viral hemorrhagic fever caused by the Henipavirus of the paramyxoviridae family. The first outbreak was recorded in Malaysian pig farms in 1998. Pteropus fruit bats are the natural reservoir of this disease. From bats, it spread to fruit products such as raw date palm juice, which humans consume. It spreads through contact with the bodily fluids of infected bats or humans. Transmission is higher in March- April during the breeding season of these fruit bats. This is the only virus that can cause encephalitis in family clusters!
The incubation period of the disease ranges from 5 -14 days. The patient first develops a fever, followed by respiratory symptoms. Human infections can fall anywhere on the radar, from mild respiratory infection to fatal encephalitis (brain inflammation). It spreads to every organ in the body but chiefly affects the heart, brain, and lungs. In severe cases, patients may develop pneumonia and respiratory distress. There are no specific risk factors. Much like Covid-19, Nipah can affect perfectly healthy individuals as well.
RT-PCR and IgM and IgG ELISA antibody testing are used to diagnose cases. Serological tests can only diagnose cases after 8-10 days of onset. This is a problem as the virus has such an indolent course. RT-PCR is used for early detection of viral RNA. Nipah virus is a biosafety level 4 pathogen (highly infectious organism with high mortality, no specific treatment, posing a very high risk to the handler and community). It can only be cultured in BSL4 labs. Molecular tests can be done in BSL3, however.
There is no specific treatment other than supportive treatment. Ribavirin has been found to be effective in some cases. The Australian Hendravirus has also been found to be similar to Nipah. Monoclonal antibodies against hendravirus may be put to use in future outbreaks. 40-75% of people who contracted the virus in the past few decades did not survive. Survivors may face personality changes or seizures. Outbreaks are managed by immediate isolation of cases, contact tracing and quarantine, culling infected animals, and prevention of contact and droplet transmission among humans.
In the past, it took six months to identify the Nipah virus in Malaysia during the first outbreak. In Bangladesh, it took three years. And in India, five years. Early detection can prevent a secondary wave of infection. Awareness of disease symptoms plays a crucial role in managing future outbreaks. Join hands and help fight the war on germs!
Citations:
Conroy, G. (2023). Nipah virus outbreak: What scientists know so far. Nature. https://doi.org/10.1038/d41586-023-02967-x Containing a nipah virus outbreak with g arunkumar. (n.d.). ASM.Org. Retrieved September 27, 2023, from https://asm.org:443/Podcasts/MTM/Episodes/094-Containing-a-Nipah-virus-outbreak-with-G-Arunk Nipah virus. (n.d.). Retrieved September 27, 2023, from https://www.who.int/news-room/fact-sheets/detail/nipah-virus Nipah virus infection—Bangladesh. (n.d.). Retrieved September 27, 2023, from https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON442 Nipah virus (Niv) | cdc. (2022, October 19). https://www.cdc.gov/vhf/nipah/index.html