Nipah virus (NiV) infection is a new emerging zoonotic disease (transmissible from animals to humans) affecting both animals (pigs and other domestic animals) and humans. Fruit bats of the Pteropodidae Family, Pteropus genus are the natural host for the virus.
NiV was first identified in Malaysia in 1998, during an outbreak of disease that occurred in a place called Kampung Sungai Nipah. Pigs were the intermediate hosts in this outbreak and most of the human cases resulted from exposure to ill pigs. After that in Singapore during March 1999 eleven abattoir workers developed NiV infection following close contact with imported pigs from Malaysia.
Outbreak of Nipah virus infection was reported in Bangladesh in 2001. Since then, outbreaks of Nipah virus encephalitis have been reported almost every year in selected districts of Bangladesh. Consumption of raw date palm sap contaminated by flying bats was the primary source of human NiV infection in Bangladesh.
In India outbreaks of NiV infection were reported from Siliguri (January-February 2001) and Nadia (April-2007) districts in West Bengal. Seventy one cases with 50 deaths (70% of the cases) occurred in two outbreaks. Recently in May 2018 an outbreak of NiV infection is reported from Kerala.
Outbreaks reported from South-East Asia have a seasonal pattern with occurrence during winter and spring (December-May). This pattern could be associated with several factors like the breeding season of the bats, increased shedding of virus by the bats and the date palm sap harvesting season. Nipah cases may occur in a cluster or as an outbreak.
There is strong evidence that loss of natural habitats of bats by human activity may attribute to emergence of bat-related viral infection communicable to humans and animals.
Chadha MS, Comer JA, Lowe L, Rota PA, Rollin PE, Bellini WJ, et al. Nipah virus and encephalitis outbreak, Siliguri, India. Emerg Infect Dis. 2006 Feb; 12(2): 235-240 http://dx.doi.org/10.3201/eid1202.051247
Symptoms of disease may appear with in 5 to 14 days (incubation period) after an exposure to infection:
Nipah virus (NiV) infection is caused by a virus, that is named after the Malaysian village where it was first discovered. NiV is a member of the family Paramyxoviridae, genus Henipavirus.
Mode of transmission-
Fruit bats of the genus Pteropus have been identified as natural reservoirs of NiV. Bats are symptomless carriers of NiV, but infected bats shed virus in their excretion and secretion such as saliva, urine, semen and excreta. The NiV is highly contagious among pigs and spreads by coughing.
Transmission of disease can occur-
Laboratory confirmation of NiV Infection in a suspected case of NiV can be done during the acute and convalescent phases of the disease by using a combination of tests.
There is no effective treatment for NiV disease, Intensive supportive care is the primary treatment for human cases, though use of an antiviral medication (ribavarin ) may reduce the symptoms of nausea, vomiting, and convulsions.
Treatment is mostly focused on managing fever and neurological symptoms. Severely ill individuals may require the use of a ventilator.
A vaccine is being developed.
Nipah virus infection can be prevented by-