The recent outbreak of the Nipah virus in the state of Kerala in India has highlighted the problem of new and emerging viruses that are causing fatal infections in humans and animals. In recent years, the occurrence of zoonosis, that is diseases that are transmitted to humans from animals, has been growing rapidly. The natural host for the Nipah virus is fruit bats and the first outbreak of the disease was identified in Malaysia in 1998. In some cases, it has also been seen that sometimes pigs also serve as the intermediate hosts for Nipah virus.
While in many Nipah virus outbreaks, it has been observed that there were no intermediate hosts. For example, consumption of contaminated date palm sap that has been infected by fruit bats can also lead to an outbreak of Nipah virus infection. Human to human transmission of Nipah virus has also been documented. To understand the recent outbreak of Nipah virus infection better, lets us find out what exactly is the Nipah virus, how it is transmitted, what are the symptoms, treatment options, and whether or Nipah virus infection is contagious.
What is the Nipah Virus?
The Nipah virus (NiV) is a fairly new virus that causes severe disease in both animals and humans. The virus is a zoonosis, meaning that Nipah virus gets transmitted from animals to humans. In the case of Nipah virus, the animal which transmits this infection is Fruit bats from the Pteropus genus or the Pteropodidae Family. First identified in 1998 during an outbreak in Malaysia, the virus is named after the village it was discovered in – Kampung Sungai Nipah Village. Nipah virus, along with the Hendra virus, has been made into a new genus known as Henipavirus, under the subfamily Paramyxovirinae.
Fruit bats have been identified to be the natural carriers of Nipah virus (NiV) and even certain pigs are known to be the intermediate carriers of the virus. Due to the abundance of fruits bats all over South Asia, Nipah virus (NiV) outbreaks are more likely to occur in these affected countries. However, fruits bats are known to be migratory in nature, and therefore it is possible for the virus to crop up in unexpected places. So far, the Nipah virus (NiV) has infected 477 people and killed 252 people since 1998.
Outbreaks of Nipah virus infection have been observed to follow a strong seasonal pattern and have a limited geographical range till now. Usually, during a Nipah virus outbreak, the fatality rate of NiV infections have been seen to range between 50-75%, though it is possible for it to be as high as 100% in some outbreaks.
How Does Nipah Virus Get Transmitted?
Infected fruit bats shed the virus through their excretion and also through bodily secretions such as saliva, semen, and urine. However, these infected bats are usually symptom less carriers. Amongst pigs, though, the Nipah virus (NiV) is severely contagious and spread by coughing. In fact, coming into direct contact with infected pigs are known to be the predominant mode of transmission of the virus to humans. In the 1998 Nipah virus outbreak in Malaysia, 90% of the infected individuals were pig farmers or had some form of contact with pigs.
Drinking of fresh date palm sap is also known to be an indirect method of transmission of the Nipah virus to humans.
The Nipah virus also passes through contaminated fruits, for instance, if there are half-eaten fruits left by the fruit bats and someone else comes in contact with these, there is a high risk of catching the Nipah virus.
In the latest outbreak in Kerala, India, we are seeing evidence of human to human transmission as health workers are becoming infected.
Is the Nipah Virus Infection Contagious?
Yes, the Nipah Virus Infection is highly contagious.
What are the Symptoms of Nipah Virus Infection?
When humans become infected with Nipah virus infection, it causes an asymptomatic infection. Within 5 to 15 days of being exposed to the virus, the symptoms of the infections start becoming visible. The common signs and symptoms of a Nipah virus (NiV) infection include:
- Vomiting and/or nausea.
- A headache.
- Mental confusion
- Some people may have symptoms of epilepsy
- Respiratory distress or illness during the start of the infection
The initial symptoms of Nipah virus begin with a fever, a headache and drowsiness, followed by mental confusion and disorientation. From the time these symptoms of Nipah virus infection appear, an infected person can slip into a state of coma within 24 to 48 hours itself.
The Nipah virus is also associated with inflammation in the brain, due to which the fever may spike, leading to a state of confusion and delirium. Many patients may also experience respiratory, neurological, and pulmonary symptoms. Encephalitis is also another complication of Nipah virus (NiV).
How is Nipah Virus Infection Diagnosed?
Laboratory diagnosis of Nipah virus (NiV) includes histopathology, serology, virus isolation, and PCR. The Serum Neutralization Test, ELISA test, and RT-PCR are used for getting a laboratory confirmation.
What is the Treatment for Nipah Virus Infection?
There is currently no treatment available for a Nipah virus (NiV) infection. The treatment is only limited to providing supportive care to alleviate the symptoms of Nipah virus infection and give patient some comfort. However, the WHO points out that as with any infectious diseases, it is important that all standard infection control practices are followed to avoid the spread of the Nipah virus infection. Suspected cases of Nipah virus (NiV) infection have to be isolated and intensive supportive care has to be given to patients suffering from Nipah virus infection. The drug Ribavirin has shown to be effective in in vitro tests, but the drug has not been proven to be effective in human testing.
Prevention and Care in Nipah Virus Infection
As there is no vaccine available for Nipah virus (NiV) infection, the only way is to prevent becoming infected in the first place. Stay away from having date palm, as drinking raw date palm sap is known to cause Nipah virus (NiV).
- As the virus is contagious, it is necessary that healthcare providers in affected areas raise awareness about the infection’s symptoms and transmission methods to avoid human to human infections.
- Anyone who experiences any of the symptoms should immediately get tested at a certified laboratory or facility.
- Direct contact with infected bats, pigs and humans in affected regions has to be avoided. Awareness about the virus and how it spreads is necessary to prevent future outbreaks.
- Hospital workers and caretakers are at a high risk of getting infected with the virus as the virus is highly contagious.
Nipah virus infection is a fairly new disease that has been discovered. Spreading from animals to humans, the Nipah virus is highly contagious and proper care needs to be taken to control the spread of the Nipah virus infection. People living in and around the area where a Nipah virus outbreak has occurred, need to avoid having fruits that have been bitten by animals or birds. It is necessary to maintain good personal hygiene and also stay away from places where bats can be found in large numbers. Definitely avoid eating fruits that have fallen on the ground and also avoid coming in contact with people who are infected with the virus. If you are handling patients having Nipah virus (NiV), then make sure you wear a mask and gloves while handling them. A little bit of precaution can go a long way in preventing the spread of the Nipah virus infection.
- World Health Organization (WHO) – Nipah Virus Infection: https://www.who.int/health-topics/nipah-virus-infection
- Centers for Disease Control and Prevention (CDC) – Nipah Virus: https://www.cdc.gov/vhf/nipah/index.html
- National Center for Biotechnology Information (NCBI) – Nipah Virus: A Potential Therapeutic Target: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5960129/
- World Organization for Animal Health (OIE) – Nipah Virus: https://www.oie.int/en/disease/nipah-virus/
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