29 May 2018 //

A Newly Emerging Zoonosis: An Outbreak of the Nipah Virus in India

An Outbreak of Nipah Virus in India

Originated from a village named Sungai Nipah which is located in the Malaysian Peninsula, where an outbreak of encephalitis (inflammation of the brain) and respiratory illness once occurred among pig farmers, Nipah Virus (NiV) is now a disease included in the World Health Organization’s priority list of emerging diseases that may cause a global pandemic—alongside Zika and Ebola. Recently, this rare and deadly Nipah virus has emerged as an outbreak in the southern part of India, killing at least 11 people and causing more than 25 others to be hospitalized.

Nipah virus is a newly emerging zoonosis which causes humans to be infected through its natural host of fruit bats. This disease may cause ranges of clinical presentation, being a fatal encephalitis as the worst case. There is currently no vaccine for humans of animals, and the primary treatment for this disease is through intensive supportive care.

 The Transmission of Nipah Virus

Transmission may occur after having direct contact with infected bats, infected pigs (via respiratory droplets, throat or nasal secretions, or their contaminated tissues), or from other NiV infected people. Drinking raw date palm sap which NiV-infected fruit bats had also sipped and contaminated may also risk the transmission of NiV to humans, as it happened in the NiV outbreak in Bangladesh (2001 to 2007). A 31-year-old nurse who had been treating Nipah patients in the latest outbreak was reported to be infected by the virus.

Smears of Virus Nipah in the cerebrospinal fluid of an infected patient. Source: India Today

 

Nipah Virus Pathological Process in the Body

When the virus finds its way to the human body, there will be an incubation period which may last for 5 to 14 days. After that, patients would usually develop 3-14 days of fever and headache. Some people may also experience atypical pneumonia and severe respiratory problems. In severe cases, patients may develop encephalitis (the inflammation of the brain which is marked by dizziness, drowsiness, and altered consciousness) and seizures which may progress to coma within 24 to 48 hours. The case fatality rate is estimated at 40% to 75%—which varies according to local capabilities for surveillance and clinical management.

The infection of NiV to the human’s respiratory pathway and the brain may be explained through its pathogenesis in the human body. According to studies, NiV would initially targets the respiratory system before spreading to the nervous system as such the brain. NiV would then latch onto proteins called ephrin-B2 and ephrin-B3 which are located on the surface of nerve cells and the endothelial cells lining the blood and lymph vessels. Most patients who died, pass away as a result of to an inflammation of the blood vessels and the swelling of the brain.

 

Relatives and hospital officials wearing safety masks at the burial of a Nipah virus victim, at Kannam Parambu graveyard. Photograph: PTI Photo. Source: rediff

 

Can Nipah Be the Next Ebola?

Although considered as a disease that may emerged as a global pandemic, infection occurrence is not as simple as the Ebola and measles. For a disease to spread globally, each person must infect at least more than one person, yet according to the CDC, a NiV-infected person tends to only infect one or zero person. In parallel, a person with measles can infect 10 others who aren’t vaccinated and Ebola (2014) can infect between one and three others, in average.

Yet, preparedness is compulsory as the virus could evolve and adapt to that human-specific environment while being in the human body—the worst-case scenario being a future strain that may transmit more easily among humans. Thus currently, the WHO and many global health experts are urging research on NiV vaccine and more effective treatments.

 

Forest officials in the south Indian state of Kerala is testing to see if a bat might be carrying the Nipah virus, Source: TIME

 

Prevention of Nipah Virus

As NiV is a zoonosis, prevention can be done by avoiding contact to sick pigs and bats and by not drinking raw date palm sap in endemic areas. Surveillance and awareness by the government will surely help in preventing future outbreaks.

Research to investigate questions of ecology of bats and Nipah virus—including its seasonality and emergence cycles, effective vaccine and reliable assays for early detection in humans and animals, and the reinforcement of better infection control in communities and hospital settings is important in controlling future outbreak of NiV.

For now, the Coalition for Epidemic Preparedness Innovations (CEPI), a global coalition that aims to derail epidemics by speeding up the development of vaccines, will be granting $25 million to two American biotech companies to accelerate their work in producing NiV vaccine. It should be of note that researchers have currently tested experimental Nipah vaccines on animals, but have yet to conduct clinical trials.

 

Alessa Fahira
Indonesia One Health University Network
Communication and Networking Team

References

  1. Nipah virus infection [Internet]. World Health Organization. 2018 [cited 23 May 2018]. Available from: http://www.who.int/csr/disease/nipah/en/
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  3. Susan Scutti C. Nipah virus: What you need to know [Internet]. CNN. 2018 [cited 23 May 2018]. Available from: https://edition.cnn.com/2018/05/23/health/nipah-virus-explainer/index.html
  4. What You Should Know About the Nipah Virus Outbreak [Internet]. Time. 2018 [cited 23 May 2018]. Available from: http://time.com/5287104/nipah-virus-outbreak-india/
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  6. Singh M. Here’s what we know about the deadly Nipah virus [Internet]. Science News. 2018 [cited 26 May 2018]. Available from: https://www.sciencenews.org/article/here-is-what-we-know-about-deadly-nipah-virus
  7. Nipah Virus (NiV) | CDC [Internet]. Cdc.gov. 2018 [cited 26 May 2018]. Available from: https://www.cdc.gov/vhf/nipah/index.html