Nipah Virus
In 1999, a severe outbreak of an unknown disease plagued farmer communities in Malaysia and Singapore. Although only about 300 confirmed cases were reported, more than 1/3 of those succumbed to death [1,2]. After extensive tracing and analysis, the infection was confirmed to be caused by a virus that originated from fruit bats [2,3]. It was later named the Nipah virus, referencing the Sungai Nipah village that unfortunately suffered from the first wave of the virus outbreak [1].
1. How does the Nipah virus spread?
Nipah virus is a zoonotic virus, which means that it has the ability to spread from an animal to humans [2]. During the initial outbreak, it was discovered that the virus had first transmitted from infected bats to pigs. Then, Nipah virus spread within the pig population and eventually found its first human host after farmers came in close contact with the infected pigs [1]. There is also solid evidence of person-to-person transmission of the virus as well as human infection due to consumption of date palm sap contaminated (e.g. bitten) by infected bats.
However, the Nipah virus is much less contagious than the viruses that cause, for instance, the flu or COVID-19. This is because its only way of transmission is when a healthy individual comes into direct contact with body fluids (most commonly being saliva and urine) of the infected individual [2,3].
2. Symptoms and consequences
The most common symptom that an individual may develop after contracting the Nipah virus is brain inflammation. This may manifest as fever and headache in the early stages, but has a likelihood of developing into nervous system damage, which most commonly leads to a coma [1,5].
3. Why do we care?
During its initial outbreak in 1999, the Nipah virus first spread to pigs before infecting humans. More than a million pigs ended up being euthanized in order to cut off the virus spread, which resulted in a huge economic burden on affected farmers and governments [1]. Now, can you guess how many cases of the Nipah virus were confirmed since 1999 (up to 2021)? Although only a total of 634 cases have been confirmed worldwide, the death toll sits at 376 out of 634 – a near 60% death rate [6].
A Nipah virus outbreak was again reported in Kerala, a state in India, in September 2023. Two fatalities have since been confirmed, and local school closures and mandatory testing of close contacts are in place to prevent further spread of the virus [7].
If you are interested in reading more about infectious diseases and the spread of viruses from animals to humans, check out Spillover written by David Quammen. Interestingly, although written in 2012, the book hints at a "next human pandemic."
The virus’ high fatality rate in the human population along with the socioeconomic consequences caused, emphasizes the need for public attention to help curb its spread.
4. Are there any preventative measures?
Now this is what makes the Nipah virus even worse. As of October 2023, there are no vaccines available against it [8]. In the case of previous outbreaks, measures have been taken to reduce human contact with potential sources of infection (contaminated date palm sap, infected pigs, and infected individuals) [1,8]. Currently, the scientific community is working to develop medications that effectively alleviate symptoms after infection and vaccines that prevent the virus from breaking through our immune systems [3,9].
References
[1] “Nipah Virus (NiV).” n.d. https://www.cdc.gov/vhf/nipah/pdf/factsheet.pdf.
[2] CDC. 2020. “What Is Nipah Virus?” Centers for Disease Control and Prevention. October 30, 2020. https://www.cdc.gov/vhf/nipah/about/index.html.
[3] Yang, Sheng, and Supratik Kar. 2023. “Are We Ready to Fight the Nipah Virus Pandemic? An Overview of Drug Targets, Current Medications, and Potential Leads.” Structural Chemistry, March. https://doi.org/10.1007/s11224-023-02148-6.
[4] Mishra, Gayatree, Vishal Prajapat, and Debasis Nayak. 2023. “Advancements in Nipah Virus Treatment: Analysis of Current Progress in Vaccines, Antivirals, and Therapeutics.” Immunology, September. https://doi.org/10.1111/imm.13695.
[5] Lee, K. E., T. Umapathi, C. B. Tan, H. T. Tjia, T. S. Chua, H. M. Oh, K. M. Fock, et al. 1999. “The Neurological Manifestations of Nipah Virus Encephalitis, a Novel Paramyxovirus.” Annals of Neurology 46 (3): 428–32. https://pubmed.ncbi.nlm.nih.gov/10482278/.
[6] Geddes, Linda. 2023. “Seven Things You Need to Know about Nipah Virus.” VaccinesWork. Gavi. September 15, 2023. https://www.gavi.org/vaccineswork/seven-things-you-need-know-about-nipah-virus.
[7] Mogul, Rhea. 2023. “Indian Authorities Rush to Contain a Deadly Nipah Virus Outbreak in Kerala.” CNN. September 14, 2023. https://www.cnn.com/2023/09/14/india/kerala-nipah-virus-india-outbreak-intl-hnk/index.html.
[8] World Health Organization. 2018. “Nipah Virus.” World Health Organization: WHO. May 30, 2018. https://www.who.int/news-room/fact-sheets/detail/nipah-virus.
[9] “NIH Launches Clinical Trial of MRNA Nipah Virus Vaccine.” 2022. National Institutes of Health (NIH). July 11, 2022. https://www.nih.gov/news-events/news-releases/nih-launches-clinical-trial-mrna-nipah-virus-vaccine.
Author and designer of this learning module: Jason Yu
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