Recently, news about the Nipah virus (NiV) has sparked widespread concern on social media.
Due to the high fatality rate of this virus and its multiple outbreaks, many netizens are worried that it will become the next global pandemic threat like COVID-19.
To help everyone understand this virus scientifically and rationally, I will provide an in-depth interpretation for you from the nature of the Nipah virus, its transmission routes, preventive measures, and its potential impact on our country.
What is the Nipah virus?
The Nipah virus is a highly lethal zoonotic virus, first identified in 1998 in a pig farmer near the Nipah River (Sungai Nipah) in Malaysia, which led to 265 infections, 105 deaths, and the culling of over 1.1 million pigs.
Research has found that the Nipah virus is mainly divided into two genetic lineages , named after their places of initial discovery:
Malaysian strain (NiV-M): Mainly outbreaks in Southeast Asia, with clinical manifestations mainly encephalitis, and human-to-human transmission is relatively rare.
Bangladesh strain (NiV-B): Mainly prevalent in Bangladesh and India. Compared to NiV-M, this strain shows greater genetic heterogeneity, is more likely to cause severe respiratory diseases, and has a significant increase in human-to-human transmission.
The most alarming feature of the Nipah virus is its extremely high case fatality rate, which varies between 40% and 94% depending on the outbreak records in different regions.
Therefore, the World Health Organization (WHO) has listed the Nipah virus as a priority pathogen for research, and the US Centers for Disease Control and Prevention (CDC) has classified it as a Category C biothreat. Its potential threat stems from the following points:
Its natural host—the fruit bat has a wide geographical distribution.
It has the ability to infect a variety of mammals (including pigs, horses, cats, dogs, etc.) .
There is currently no approved human vaccine or specific drug available.
How does it spread?
The transmission chain of the Nipah virus is complex, involving multiple interactions between wildlife, livestock, and humans.
Fruit bats (Pteropus genus) are considered the natural reservoirs of the Nipah virus. These bats typically do not show symptoms after infection but intermittently shed the virus through saliva, urine, and feces.
When human activities (such as deforestation, urbanization) disrupt the natural habitats of bats, bats migrate to orchards or areas near human settlements to forage, thereby increasing the risk of virus spillover from wildlife to humans.
Direct contact with contaminated food is the most common mode of transmission in India and Bangladesh. Fruit bats often feed on date palm sap at night, and their saliva or urine can contaminate the sap in collection vessels. Humans are highly susceptible to infection after consuming this raw sap. Additionally, consuming fruits bitten by bats and left with saliva is also a source of infection.
In the Malaysian outbreak, fallen fruit from bats entered pigpens, leading to pig infections and widespread transmission, with humans getting infected through contact with respiratory secretions or body fluids from sick pigs. In the Philippines, horses were also found to act as intermediate hosts.
The virus is mainly transmitted from person to person through respiratory droplets or direct contact with the infected person’s body fluids (such as saliva, urine, blood) . Therefore, healthcare settings and home care are high-risk environments for transmission.
Will it spread within the country?
This is the most concerning question for many people. According to existing information, the likelihood of the Nipah virus causing large-scale transmission in our country is extremely low, but vigilance is still required.
Firstly, fruit bats are mainly distributed in South and Southeast Asia. Although there are related bat species in some southern provinces of our country, and serological surveys have detected viral antibodies in bats from many Southeast Asian countries, so far, no human Nipah virus infection cases have been reported in China.
Our country has extremely strict inspection and quarantine systems for pig farming and international live animal trade. The large-scale amplification and human transmission through pig herds as seen in the 1998 Malaysian outbreak, is hard to replay under the modern epidemic prevention system. China has also established a mature infectious disease surveillance network. For fever, encephalitis, or severe respiratory symptoms in returning personnel, the disease control department has the ability to screen and identify quickly.
Additionally, the basic reproduction number (R0) of the Nipah virus is usually significantly lower than that of the novel coronavirus. In most outbreaks, its R0 is close to or less than 1.1 , which means that without specific environmental (for example, unprotected medical environments) support, it is difficult to form a sustained chain of human-to-human transmission.
Basic Reproduction Number R0
The basic reproduction number R0 refers to the average number of healthy people one person with a certain infectious disease can infect without any external intervention (for example, no vaccines, no isolation, no immunity) , it is a core indicator for measuring the transmission capacity of infectious diseases , the higher the value, the more easily the disease is naturally transmitted.
How can we prevent it? What should we pay attention to in daily life?
Faced with a virus that has an extremely high fatality rate and no specific drugs, “prevention” is the only hard truth.
1. Personal Life Prevention
The most critical point is to strictly prohibit the consumption of untreated raw date palm sap or palm sap. In threatened areas, all collection containers should have bat-proof devices (such as covered with bamboo mats) .
Do not pick up fruits that have fallen on the ground, especially those with tooth marks or claw marks ,all fruits should be thoroughly washed before consumption.
Additionally, maintain good hand-washing habits, especially after contact with animals or suspected contaminated environments.
2. Be Alert for the Following Symptoms
If the following symptoms occur, and there is a recent travel or contact history in Southeast or South Asian regions, seek medical attention immediately:
Initial Symptoms : High fever, headache, muscle aches, vomiting, sore throat, and other non-specific symptoms similar to the flu.
Respiratory System Manifestations : Cough, shortness of breath, severe cases can quickly develop into acute respiratory distress syndrome (ARDS) .
Nervous System Manifestations : Disorientation, somnolence, confusion, convulsions, and even coma, which are typical signs of encephalitis.
3. Medical and Community-Level Prevention and Control
Suspected cases should be immediately placed in single rooms, preferably negative pressure isolation wards. Medical staff must strictly follow contact, air, and droplet precautions when caring for patients, wearing N95 masks, gloves, goggles, and protective clothing.
In summary, the Nipah virus is not the novel coronavirus. Its transmission mainly depends on close-range bodily fluid contact or contaminated specific foods, and unlike the novel coronavirus, it does not have a strong ability to spread through the air. As long as we avoid direct contact with wild bats and their secretions, do not drink raw palm sap, reduce travel to epidemic areas, or pay attention to fruit hygiene in epidemic areas, the risk to the general public is very small.
However, due to its high fatality rate and the current lack of drugs, we must not take it lightly. The emergence of this virus is a test of the global human monitoring system. Strengthening international cooperation, improving grassroots diagnostic capabilities, and accelerating vaccine research and development are the necessary paths to deal with this “Disease X”.
Peer Review Expert Zhang Lei
Distinct Health Pediatrician, Allergist, Children’s Respiratory & Asthma Specialist
Harbin Medical University Doctorate
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