Nipah kills two in Kerala: What is this virus – The Core IAS

Nipah kills two in Kerala: What is this virus

What is the Nipah virus infection?

  • As per the World Health Organisation (WHO), Nipah Virus (NiV) infection is a newly emerging zoonosis that causes severe disease in both humans and animals.
  • It is a zoonotic disease, which means it is transmitted to humans through infected animals or contaminated food. It can also be transmitted directly from person to person through close contact with an infected person.
  • Nipah Virus is an airborne transmission infection and can affect those who come in direct contact with contaminated bodies such as pigs or bats carrying the virus.
  • Infected bats shed the virus through excreta and secretions. Human-to-human transmission has also been documented.
  • NiV is also capable of causing disease in pigs and other domestic animals.
  • Direct contact with pigs is the prime mode of transmission of the virus in humans.
  • The organism which causes Nipah Virus encephalitis is an RNA or Ribonucleic acid virus of the family Paramyxoviridae, genus Henipavirus, and is closely related to Hendra virus.
  • Hendra virus (HeV) infection is a rare emerging zoonosis that causes severe and often fatal disease in both infected horses and humans.

How is Nipah transmitted?

  • The first outbreaks of the Nipah virus among humans was reported from Malaysia (1998) and Singapore (1999). The virus takes its name from the village in Malaysia where the person in whom the virus was first isolated died of the disease.
  • The transmission from animals happens mainly through consumption of contaminated food. Transmission can happen due to “consumption of raw date palm sap or fruit that has been contaminated with saliva or urine from infected bats. Some cases of NiV [Nipah] infection have also been reported among people who climb trees where bats often roost.”
  • The animal host reservoir for this virus is known to be the fruit bat, commonly known as flying fox. Fruit bats are known to transmit this virus to other animals like pigs, and also dogs, cats, goats, horses and sheep.
  • Humans get infected mainly through direct contact with these animals, or through consumption of food contaminated by saliva or urine of these infected animals. But human-to-human transmission is also considered possible. 
  • Since it was first identified in 1998-99, there have been multiple outbreaks of the Nipah virus, all of them in South and Southeast Asian nations. In Bangladesh, there have been at least 10 outbreaks since 2001.

Nipah Virus India 

  • The year 2001 saw the first outbreak of Nipah Virus in Siliguri, India followed by the 2007 outbreak in Nadia of West Bengal. 
  • The 2018 outbreak of Kerela was declared over soon after it was localized in Kozhikode and Malappuram districts of Kerala.
  • In Kochi, another case was seen in June 2019.

How fast does the Nipah virus spread?

  • The Nipah virus is known to spread far more slowly than SARS-CoV-2. 
  • However, so far, all outbreaks of the Nipah virus have been localised and contained relatively quickly. One of the main reasons for a relatively quick end to an outbreak is the fact that Nipah virus is not very infectious and human-to-human transmission is not very easy.
  • The reproductive number (R0) in the previous outbreaks of Nipah virus was about 0.48. The R-value is a measure of how quickly the virus spreads in the population. A value less than one means less than one person is being infected by an already infected person. In such a scenario, the outbreak is expected to diminish relatively quickly.

Symptoms of the Nipah infection

  • Nipah Virus is usually associated with inflammation of the brain due to which several days of fever can often lead to a state of confusion, disorientation and even persistent drowsiness.
  • Encephalitis may also emerge as an acute or late-onset and can be a fatal complication of NiV.
  • Neurological, respiratory and pulmonary signs also emerge in an infected individual.
  • Some common signs and symptoms of NiV are fever, headache, cough, sore throat, difficulty in breathing, vomiting, drowsiness, dizziness, nausea, fever, headache and mental issues such as confusion.
  • In severe cases, disorientation, drowsiness, seizures, encephalitis (swelling of the brain) can occur, progressing to coma and death.
  • Typically, the human infection presents as an encephalitic syndrome marked by fever, headache, drowsiness, disorientation, mental confusion, coma, and potentially death. During the outbreak in Malaysia, up to 50 per cent of clinically apparent human cases died. There is no specific treatment for Nipah Virus. The primary treatment for human cases is intensive supportive care.

Prevention of the Nipah infection 

  • While there is no vaccine available for the infection, preventive measures can be a key to control the spread. With fruits bats being the primary cause of infection, the farm animals should be prevented from eating fruit contaminated by bats. Consumption of contaminated date palm sap including toddy should also be avoided. Physical barriers can be put in place in order to prevent bats from accessing and contaminating palm sap.
  • Medical officials who are looking after the patients with suspected or confirmed NiV should take basic precautions like washing hands, using a gown, cap mask and wearing gloves. For laboratory personnel. 
  • In case of animals, wire screens can help prevent contact with bats when pigs are raised in open-sided pig sheds. Run-off from the roof should be prevented from entering pig pens. practice. Early recognition of infected pigs can help protect other animals and humans. Due to the highly contagious nature of the virus in swine populations, mass culling of seropositive animals may be necessary.

Nipah Virus and Fruit Bats

  • Fruit bats belong to the Pteropodidae Family – Pteropus genus.
  • They’re also known as flying foxes.
  • Found in South East Asia.
  • The Nipah Virus can survive in the bat’s body without causing disease, allowing it to jump to susceptible mammals like humans or pigs when bats come in contact with them.
  • Antibodies were found in the Indian Flying Fox during the Bangladesh outbreak. 
  • The Indian Flying Fox, hosts over 50 viruses. With around 1,200 species, bats comprise 20% of the earth’s mammalian diversity. Long periods of flying raise the temperatures of bats, boosting their immune responses and helps them survive the microbes’ pathogenic effects.