Natural Animal Host Reservoir
- Fruit bats, commonly known as flying foxes, serve as the primary reservoir for the Nipah virus. These bats transmit the virus to animals such as pigs, dogs, cats, goats, horses, and sheep.
- Human infection mainly results from direct contact with these animals or consumption of food contaminated by their saliva or urine.
Outbreaks in South and Southeast Asia
Outbreaks have occurred in South and Southeast Asian countries since its identification in 1998-99.
- Bangladesh has experienced at least 10 outbreaks since 2001.
- India has witnessed outbreaks in West Bengal (2001, 2007) and Kerala (2018, 2019, 2021).
Nipah Virus Spread and Mortality
- It spreads more slowly than COVID-19 but has a higher mortality rate.
- Mortality rates in past outbreaks have ranged from 68% to 100%.
- During the 2018 Kerala outbreak, 17 out of 18 confirmed patients died.
- All outbreaks so far have been localized and contained relatively quickly.
- A study observed that the reproductive number (R0) was approximately 0.48 during previous outbreaks. The R-value serves as an indicator of the virus’s rate of spread within the population. When this value is less than one, it implies that less than one person is getting infected by an already infected individual. In such circumstances, the outbreak is anticipated to subside relatively rapidly.