Nipah virus

Nipah virus
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Name	Nipah virus
Caption	Colorized transmission electron micrograph of Nipah virus particles (blue) from a clinical isolate.
Taxon	Nipah henipavirus
Order	Mononegavirales
Family	Paramyxoviridae
Genus	Henipavirus
Species	Nipah henipavirus

Nipah virus is a zoonotic pathogen belonging to the genus Henipavirus within the family Paramyxoviridae. It was first identified during an outbreak among pig farmers in Malaysia in 1998. The virus is notable for causing severe disease in both animals and humans, with fruit bats of the genus Pteropus serving as its natural reservoir. Outbreaks have been recorded in several Asian countries, leading to significant public health concerns due to high mortality rates and the potential for human-to-human transmission.

Virology

Nipah virus is an enveloped, single-stranded, negative-sense RNA virus. Its genome organization is typical of members of the Paramyxoviridae, encoding six major structural proteins: nucleocapsid, phosphoprotein, matrix protein, fusion protein, glycoprotein, and large protein (RNA-dependent RNA polymerase). The virus is closely related to Hendra virus, another member of the Henipavirus genus. Research into its virology is conducted at institutions like the Centers for Disease Control and Prevention and the World Health Organization collaborates on global studies. The International Committee on Taxonomy of Viruses officially classifies it as *Nipah henipavirus*.

Transmission

Primary transmission occurs from the natural reservoir, Pteropus fruit bats, to other animals or humans through contact with contaminated secretions, such as bat urine or saliva on partially consumed fruit. In the initial outbreak in Malaysia, infected pigs acted as amplifying hosts, transmitting the virus to humans. Direct human-to-human transmission has been documented in subsequent outbreaks, particularly in Bangladesh and India, often through close contact with infected patients' respiratory secretions or bodily fluids. The role of intermediate hosts like pigs was also observed in Singapore.

Symptoms and diagnosis

Infection can range from asymptomatic to acute respiratory distress and fatal encephalitis. Initial symptoms often include fever, headache, myalgia, vomiting, and sore throat, which can rapidly progress to dizziness, drowsiness, and altered consciousness. Severe cases involve seizures and progression to coma, with a high case fatality rate. Diagnosis is confirmed through laboratory testing using methods like enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR) on samples from the cerebrospinal fluid or throat swabs, and virus isolation. The National Institute of Virology in India has been instrumental in outbreak diagnostics.

Treatment and prevention

There is no licensed specific antiviral treatment for infection; management is supportive, focusing on intensive care for severe respiratory and neurological complications. The monoclonal antibody m102.4 has been used under compassionate use protocols. Preventive measures center on reducing exposure to bats and sick animals, avoiding consumption of raw date palm sap contaminated by bats, and implementing infection control practices in healthcare settings. Research into vaccines, including candidates using the ChAdOx1 platform, is ongoing, with trials supported by the Coalition for Epidemic Preparedness Innovations.

Epidemiology and outbreaks

Since its discovery in Sungai Nipah, Malaysia, major outbreaks have occurred in Bangladesh and India, with frequent, smaller annual outbreaks in Bangladesh. Significant outbreaks were recorded in Siliguri, Kozhikode, and Kerala. The virus is considered a priority pathogen by the World Health Organization in its Blueprint for Research and Development. The National Centre for Disease Control in India and the Institute of Epidemiology, Disease Control and Research in Bangladesh are key agencies in outbreak response. The geographic range of the reservoir bats extends across South and Southeast Asia.

In popular culture

The high mortality and outbreak narrative of the virus have inspired several fictional portrayals. It features in the 2011 American thriller film *Contagion*, directed by Steven Soderbergh. The virus is also a central plot element in the 2019 Indian Malayalam-language film *Virus*, which depicts the 2018 outbreak in Kerala. Furthermore, it appears in episodes of television series such as the Canadian medical drama *The Hot Zone*.

Category:Paramyxoviruses Category:Zoonoses Category:Infectious diseases