Nipah Cases Rise to 5 in Bengal; Experts Warn Against Intruding Animal Habitats

The first two patients -- a male nurse from Purba Medinipur district and a female nurse from Mongolkot in Purba Bardhaman district who worked at a private hospital in Barasat in North 24 Parganas district -- continue to remain in the ICU. All three new cases -- a doctor, a nurse, and a health staff member -- have been admitted to the infectious diseases' hospital in Beleghata.

The West Bengal government has also sent around 100 people into home quarantine since the first confirmed cases on Monday. Of these, around 30 are being closely monitored.

Human intrusion into animal habitats, primarily through deforestation and intensive farming, has been a key driver of Nipah virus (NiV) emergence. This disruption forces the natural reservoir hosts, fruit bats (flying foxes), into closer contact with human settlements and domestic animals, leading to the virus "spilling over" to new populations.

According to experts, the exact mechanism by which the virus jumps to humans is not fully known, although consumption of bat-contaminated fruit and drinking raw date palm sap have been proposed as possible routes.

"Nipah virus is known to circulate in certain species of bats. Human infection is rare and is the result of an accidental spillover at the human-bat interface, also called a zoonosis. This is more likely in rural and forest-adjacent areas where agricultural practices increase contact between humans and fruit bats searching for food," Rajeev Jayadevan, Ex-President of IMA Cochin and Convener of the Research Cell, Kerala, told IANS.

"Human-animal interphase, intruding their domains, consuming raw date-palm rack (toddy or tadi) that is contaminated by bats, eating half-eaten raw fruits that are leaked by bats," are potential reasons behind the recent outbreak, added Dr Ishwar Gilada, Secretary General of People's Health Organisation (PHO).

But can the disease potentially turn into a pandemic?

The experts noted that although person-to-person transmission can occur on a limited scale, the prevailing version of the Nipah virus does not have the characteristics of a pandemic virus.

Nipah is essentially a zoonotic infection -- from animals to humans -- and then from human to human. Nipah virus spreads through saliva, urine, and other body fluids of an infected person.

Airborne transmission through droplets among close contacts of an infected person, especially if the patient develops a cough or vomiting, is also likely. The risks can be reduced by following universal precautions, such as wearing masks and gloves while caring for patients.

"Theoretically, any zoonotic infections that spread from human to human have the potential of causing an epidemic or pandemic. But, from its first outbreak in Malaysia in 1998 till date, it has not happened," Gilada told IANS.

As there are no proven antiviral therapies or human vaccine against the Nipah virus, early detection is crucial to control an outbreak.

"Because Nipah carries a high mortality rate, it is important to arrest the spread of infection as early as possible. This requires systematic contact tracing, where all close contacts of the patient are identified, monitored for symptoms, and kept in isolation according to protocol," Jayadevan said.

If the initial diagnosis is delayed, the disease may spread further, making containment more difficult.

Importantly, the expert stressed the need for increasing public awareness, especially to avoid contact with bats.

"Misguided attempts by well-meaning individuals to trap, handle, or drive bats away can be counterproductive and may actually increase the risk of spillover. Besides, bats can fly dozens of kilometres each day, so driving a few bats away from one property will not keep them away permanently," Jayadevan told IANS.

Gilada also urged people to not intrude on the habitats and domains of animals, birds, and the environment.

"Not consuming bats, raw fruits, especially half-eaten ones, not consuming Toddy/Tadi, strict infection control precautions- SMS-sanitiser, mask, and social distancing from infected persons, etc.," he said.

"Healthcare systems must stay alert for early warning signs, which unfortunately can resemble other viral infections," added Jayadevan.

"Patients presenting with features of viral encephalitis and pneumonia in Nipah-prone areas must also be evaluated for this infection. This is especially important for patients who develop seizures, confusion, or coma," he said.

- IANS