Nipah Virus (NiV) outbreak in Kerala India

NiV (RNA virus) infection is an emerging infectious disease (EID) of global importance. The virus causes a life threatening respiratory and neurological illness (encephalitis) in animals and human (zoonosis). The current outbreak in Southern India has claimed more than 10 lives, and the havoc is not yet over. This is my first post so far, highlighting essentials of NiV illness by than and now.

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NiV zoonosis in Kerala: Rooting to epidentre

The third Indian NiV outbreak epicentre is rooted to an old well in Perambra (Koyilandy, Kozhikode, North Malabar region of Kerala). It has claimed more than 10 lives. (image source maps4news)

Kerala outbreak news facts

  • The source of NiV has been rooted to  an old well (owned by Valachekutti Moosa) in Changaroth village [Perambra, Koyilandy, Kozhikode, North Malabar region], because dead bats has been found in the well. The test report from the bats samples is awaited for clarification). For the time being the well has been sealed.
  • The family of Valachekutti Moosa has been reported as the epicentre of current outbreak. It has been assumed that the two of his son [Mohamed Saliah (age 28 year) and Mohammed Sadiq (age 26 years) who had been involved in cleaning of the well were the first to encounter with NiV infection. It is suspected that their parental aunt Mariumma (died) got infection from them. Moosa (age 62 years) and his sons wife are in critical condition. It is a sad tragedy to the family.
  • It can be also a human-to-human contact transmission, experts are sceptical to declare it.
  • The nurse Lini Puthussery the nurse who treated NiV victims died from human-human contact transmission. The dependent husband and children are now the responsibility of government of Kerala. 
  • Twelve deaths has been reported(two are from Malappuram the nearby district).
  • The suspects of NiV victims contact are set under quarantined observation. 

Cause of zoonosis and risk reduction

Humans interventions in natural habitat of the bats is the major cause of NiV zoonosis. Climate change and urbanisation have their due contribution in emerging outbreaks.

Risk reduction

  • Avoid bats to human contacts [minimisation in bats to human transmission] 
  • Handle sick animals with care [minimisation in animals to human transmission] 
  • Avoid contacts with Nipah patients [minimisation in human to human transmission] 

History of NiV and Natural Reserviors

  • NiV was identified in 1999 [from Sungai Nipah village Malasiya, during pig farmers outbreak. 
  • The 1999 outbreak caused infection to 300 people, 100 died, but it does not cause sever impact to pigs (pigs were euthanized for human safety).
  • No recurrent infection reported from Malasiya.
  • The 2001 outbreak in Bangladesh was caused from bats to human through contaminated date palm sap. It repeated annually. The strain was different from Malaysian outbreak. It was endogenous.
  • In 2001 infection were reported from Siliguri, India (in hospital settings due to person to person contacts). 
  • Now India is facing with the third NiV outbreak
  • Till date NiV outbreaks has been reported from 
  •  Pteropid fruit bats the natural reservoir of NiV are distributed across continents of Africa (Madagascar), Asia (India, China, Indonesia,  Laos, Bhutan  Brunei, Myanmar, Nepal, Philippines, Singapore, Taiwan, Thailand, Vietnam) and Australia (Papua New Guinea). 


  • It may take 5-14 days (incubation) to develop the symptoms which may last for 3-14 days. 
  • The successive symptoms of infection are: (1) Fever (2) Headache (3) Drowsiness (4) Vomiting (5) Disorientation (6) Mental confusion (7) encephalitis (brain swelling),  delirium etc.
  • Within 24-48 hrs, the symptoms may progress to coma within
  • During early phase of infection, patient may also experience sever respiratory illness. In late phase of infection, due to inflammation associated changes in brain tissues, patient may suffer with persistent convulsions and differential personality. 


  • Virus gene specific RT-PCR (real time polymerase chain reaction) from body fluids
  • Isolation of virus
  • Detection of anti-NiV antibodies by ELISA (enzyme-linked immunosorbent assay)  


Intensive care support (for treating respiratory & neurological complications) in isolation (quarantining) is the only option available. [example ICU support: for fever-give paracetamol, for dehydration-give IV fluid, for breathing problems-provide oxygen support, doctors may take all life supporting safety measures as per requirements].

There is no WHO approved vaccine available for treatment of NiV zoonosis. 

National/Sub Alertness. 

  • Kerala health ministry has issued a statement that current outbreak is limited to Kerala.  
  • Kerala government has advised travellers to avoid visit in northern Kerala (Kozhikode, Malappuram, Wayanad and Kannur districts).
  • Fear is mounted in the air, the indoor patients have evacuated the hospitals and others also avoiding visit to Kozhikode hospital. 
  • Rajasthan healthcare system is on high alert for Nipah management.
  • Karnataka; spread of virus has been suspected in neighbouring states (samples from the two suspect have been sent for testing, declaration are on hold). 
  • National Centre for Disease Control (Govt of India), is closely monitoring the progress.


Ph.D. , Indian Institute of Science Education and Research Bhopal

Ranjeet Singh Mahla, Research Scholar IISER Bhopal, (Research interest: Emerging Infectious Diseases & Antimicrobial Resistance).