Nipah Virus Case Reported in West Bengal

Nipah Virus Case Reported in West Bengal

Why in News? 

Recently, two suspected cases of the Nipah virus identified at the Virus Research and Diagnostic Laboratory at AIIMS Kalyani have drawn urgent attention to West Bengal’s public-health preparedness. 

• Both suspected cases are healthcare workers serving in a hospital located in Barasat, North 24 Parganas district. Their medical condition was described as ‘critical’. 
• Following the detection, the Union Ministry of Health and Family Welfare coordinated with West Bengal. The Central Government deployed a National Joint Outbreak Response Team to examine this. 

What is Nipah Virus (NiV)?

• About: Nipah virus is a dangerous infectious agent that belongs to the Henipavirus genus within the Paramyxoviridae family of viruses. It causes a disease known as Nipah virus infection. The infection is zoonotic, which means it naturally spreads from animals to humans and can also spread between people under certain conditions. The virus was added to the World Health Organization’s priority list due to its high fatality and potential to cause outbreaks.

• Origin: The virus was first identified during a large outbreak in Malaysia and Singapore between 1998 and 1999. In that outbreak, over 300 people became ill, and more than 100 died after close contact with infected pigs that got the virus from fruit bats. 

• Naming: The name “Nipah” is derived from the location where the virus was first isolated. It was linked to a village named Sungai Nipah in Malaysia. The early outbreak was traced to infected pigs, which acted as an intermediate host between bats and humans.

• • Transmission: The virus can enter the human body through several routes:
    • Animal-to-human transmission: Direct contact with infected animals such as bats or pigs can transmit the virus.
    • Food-borne transmission: Consumption of fruits or food products contaminated by infected bat excretions or secretions.
    • Human-to-human spread: Close contact with body fluids of infected persons can transmit the virus. This has been seen in family and healthcare settings.
  • Host: Nipah virus was first discovered in farm and domestic animals like pigs, dogs, and horses. It spreads through fruit bats, which carry the virus in their saliva, urine, and droppings.

• Symptoms: Symptoms of infection usually begin 4 to 14 days after exposure, but in rare cases, symptoms have appeared much later. Initial signs are often general and non-specific, such as: Fever and headache, Muscle pain and fatigue, Sore throat and cough, Vomiting and breathing difficulties. If the infection worsens, it can quickly affect the brain and lungs. Severe cases may develop acute encephalitis, which means inflammation of the brain.

• Case Fatality Rate: One of the most concerning features of Nipah virus infection is its high case fatality rate (CFR). Estimates from multiple outbreaks place the CFR between 40% and 75%. In some outbreaks, rates approached or exceeded 80–90%.

• Diagnosis: Early diagnosis remains critical due to Nipah’s non-specific initial symptoms like fever and headache. Real-time Polymerase Chain Reaction (RT-PCR) is the standard for detecting viral RNA. Later stages are identified via Enzyme-Linked Immunosorbent Assay (ELISA) to detect specific antibodies. 
• Treatment: There are currently no licensed vaccines or specific antiviral drugs for Nipah virus. Experimental therapies such as the monoclonal antibody m102.4 and the antiviral Remdesivir have been used on a compassionate basis.

Nipah Virus Earlier Detections in India

• 2001: The first confirmed outbreak of Nipah virus in India occurred in January–February 2001 in Siliguri, West Bengal. A total of 66 people were infected, of whom 45 individuals died from severe encephalitis and respiratory illness. The case fatality ratio was high, at about 68 percent.

• 2007: A second outbreak was reported in 2007 in Nadia district, also in West Bengal. It involved a smaller cluster of 5 confirmed patients. All individuals who tested positive for the virus died. This resulted in a 100 percent fatality rate among detected cases. The outbreak remained geographically limited.

• 2018: In May 2018, the first major outbreak in southern India occurred in Kozhikode and Malappuram districts of Kerala. There were 19 reported cases, including 18 laboratory-confirmed infections of Nipah virus. Out of these, 17 individuals died, resulting in an exceptionally high fatality rate of around 89 percent. Human-to-human transmission was significant.

• • 2019: A single laboratory-confirmed case of Nipah virus infection was detected in Ernakulam district in June 2019. This event involved one person who survived after treatment. Prompt identification and isolation helped prevent further spread in the community.

• 2023: Between 12 and 15 September 2023, Kerala reported six laboratory-confirmed cases of Nipah virus in Kozhikode district. Of these, two deaths occurred. The remainder were contacts of the first confirmed patient. Health authorities traced over 1,200 contacts, including family members and healthcare workers, and placed them under monitoring for signs of illness.

India’s Zoonotic Disease Management

• • India operates the Integrated Disease Surveillance Programme (IDSP) to detect and monitor zoonotic diseases. IDSP collects data from health facilities across states and tracks trends in both human and animal disease occurrence.

• The National Centre for Disease Control (NCDC) has developed a specialized Manual of Zoonotic Diseases. This manual provides evidence-based guidance for frontline health workers, veterinarians, wildlife officials and policymakers. The manual strengthens decision-making.

• India’s zoonotic disease management is increasingly guided by the One Health approach. The National One Health Mission (NOHM) was launched to operationalize this idea. It promotes collaboration between ministries of health, animal husbandry, agriculture and environment to share data.
• The World Bank approved USD 82 million for zoonotic disease prevention in India in 2023 to support the One Health model. It benefits states like Assam, Karnataka, Odisha, Maharashtra and Madhya Pradesh by improving veterinary services and disease response.
• India implements routine vaccination campaigns and animal health programmes for diseases like rabies and foot-and-mouth disease (FMD). Under the National Animal Disease Control Programme (NADCP), the government approved substantial funding to control FMD and brucellosis, with a long-term goal of elimination by 2030.