Why Nipah virus outbreaks are occurring only in Kerala

Why Nipah virus outbreaks are occurring only in Kerala

Why Nipah virus outbreaks are occurring only in Kerala


Since May 2018, when Kerala announced the first Nipah outbreak in Kozhikode district, there have been three more Nipah outbreaks, the most recent in late August 2023. Three of the four Nipah outbreaks in Kerala in 2018, 2021, and 2023 occurred in Kozhikode district for unknown causes; the 2019 epidemic occurred in Ernakulam district. Even after five years and four outbreaks, it is still unclear why three of the four epidemics have occurred in Kerala’s Kozhikode district. Fruit bats capable of causing Nipah virus outbreaks in people are not limited to the Kozhikode district.

Outbreaks in India

  • Nipah virus outbreaks have occurred in the Indian states of Kerala and West Bengal. In Kerala, outbreaks have been reported in Kozhikode and Ernakulam districts. Other parts of India may also have the potential for Nipah virus transmission, as evidenced by the presence of Nipah virus antibodies in fruit bats in multiple states.

Presence of Zoonotic Viruses in Animals 

  • Fruit bats, often known as flying foxes, are the Nipah virus’s (NiV) natural reservoir. The first Nipah virus case happened when people who came into contact with infected pigs became quite ill. The virus was discovered to have originated in bats, according to researchers.
  • The Nipah virus can infect both pigs and humans. The virus is most likely transferred from fruit bats to humans by the consumption of fresh date palm sap. Infected bats or pigs can transmit the virus to other animals through their bodily fluids.
  • Fruit bats are also a natural reservoir for the Hendra virus, which is closely related.

Transmission Pathways of Nipah Virus

    • Bat-to-Human Transmission: Fruit bats of the Pteropus genus, popularly known as flying foxes, are the natural reservoirs of the Nipah virus. Humans can become infected when they come into direct touch with infected bats’ saliva, urine, faeces, or other bodily fluids. Handling bats or being near regions where bats roost might cause this.
  • Consumption of Contaminated Food or Drink:
    1. Date Palm Sap: In certain epidemics, the Nipah virus has been transmitted to humans by the intake of raw date palm sap contaminated with bat saliva or urine. Bats are known to visit date palm trees to feed on the sap, and if the sap is gathered and ingested without sufficient hygiene procedures, it can lead to human diseases. (This was seen in Bangladesh)
    2. Fruits or Vegetables Contaminated with Bat Excreta: There is a danger of transmission if fruits or vegetables are cultivated in regions where bats are present and the produce becomes contaminated with bat excreta.
  • Human-to-Human Transmission: Although rare, the Nipah virus can be spread from person to person. Human-to-human transmission often happens by close contact with an infected person’s blood, saliva, organs, or other bodily fluids. This can happen in healthcare settings when healthcare personnel come into contact with infected patients’ fluids, or in families who care for sick people.
  • Transmission through intermediary hosts:
    1. Pigs: During the 1998-1999 Malaysian outbreak, pigs functioned as intermediate hosts for the Nipah virus. Bats infected pigs, and humans were infected as a result of handling or consuming infected pigs or their products. This route is less common, but it can pose a substantial risk in locations where pig rearing is common.
    2. Other Animals: Animals other than pigs may function as intermediary hosts in some cases. Horses and other livestock are examples of this.
  • Nosocomial Transmission: Nosocomial transmission occurs in hospitals when healthcare staff or other patients come into touch with infected surfaces, equipment, or fluids.

How was Kerala able to hold disease at bay before it became a pandemic?

  • Surveillance and early detection: Case detection had to be done quickly. Kerala’s healthcare system was extremely watchful in detecting and reporting uncommon ailments. There were robust surveillance procedures in place, including the formation of teams comprised of virologists to assess undiagnosed fever cases for probable Nipah virus infection.
  • Quick Isolation and Quarantine: Individuals infected with the virus were swiftly identified and isolated to prevent the infection from spreading further. Close contacts were quarantined and symptoms were thoroughly monitored.
  • Communication and coordination: The state administration built efficient coordination systems in partnership with central government organizations and the World Health Organization (WHO).To keep things open and calm the public, regular updates and communication were given.
  • Contact tracing and monitoring: Careful contact tracing was done to find and keep tabs on people who had had frequent interaction with confirmed cases. These contacts underwent routine health exams and symptom monitoring.
  • Healthcare System: Kerala’s efficient management of the outbreak was greatly aided by its excellent healthcare system. Hospitals had what they needed to treat Nipah patients and handle the situation.

What are the challenges faced by the health sector when handling the Pandemics like Nipah virus in the country?

  • Early Detection: Early Nipah virus detection and diagnosis are essential to stopping the infection’s spread. However, because the symptoms of the Nipah virus are similar to those of other prevalent infections, diagnosing it can be difficult. To promptly identify and confirm instances, health systems need to have strong surveillance and diagnostic capabilities.
  • Risk Assessment: Health officials must accurately determine the risk presented by the virus and make this information available to the public. During a pandemic, misinformation and panic can spread quickly, so effective and prompt communication is crucial to keep people informed and calm.
  • Resources Under Pressure: Combating a pandemic puts a significant demand on healthcare resources. There could be a lack of medical supplies such as personal protective equipment (PPE), ventilators, and drugs as well as an overcrowding of patients in hospitals. It is essential to plan for such resource limitations.
  • Infection Control and Prevention: Nipah virus is extremely contagious, and healthcare personnel are at a higher risk of infection than the general public. To safeguard patients and healthcare staff, it is crucial to implement effective infection control measures, which include the use of PPE, case isolation, and stringent cleanliness guidelines.
  • Public Health Infrastructure: A nation’s ability to respond to a pandemic is greatly influenced by its public health infrastructure. A robust healthcare system that has the resources, staff, and facilities is better able to meet the problems posed by Nipah and other pandemics.