UK health authorities have issued a stark warning regarding the Nipah virus, highlighting its potential to cause fatality in up to 75 percent of infected individuals. This rare yet serious infectious disease, primarily carried by bats, can infect both pigs and humans, often leading to irreversible brain damage. The UK Health Security Agency (UKHSA) has updated its guidance amid global pandemic fears, advising travelers to areas where the virus circulates to understand the risks, even though the immediate risk to most people remains very low.

Currently, there is no vaccine or specific treatment for Nipah virus infection. Estimates suggest a mortality rate between 40 and 75 percent, with survivors frequently experiencing lasting neurological difficulties such as persistent seizures and personality changes. Health officials also note the virus's rare ability to lay dormant and reactivate months or even years after the initial infection, a factor contributing to its designation as a 'high priority pathogen' in March last year, underscoring an urgent need for investment in developing diagnostic tests, treatments, and vaccines.

The primary mode of Nipah infection in humans often involves consuming fruits or fruit juices, particularly fermented date palm juice, contaminated with feces, urine, or saliva from infected fruit bats. The virus can trigger severe breathing problems, seizures, and fatal swelling of the brain (encephalitis). While initial outbreaks were linked to contact with infected pigs, person-to-person spread can occur through close contact and bodily fluids, posing a particular concern for healthcare professionals. This human-to-human transmission was observed in the recent outbreak in West Bengal, India.

For individuals traveling to endemic regions like Bangladesh and India, prevention is key. Recommendations include strictly avoiding direct contact with bats and taking rigorous precautions with food preparation. All fruit should be thoroughly washed with clean water and peeled before consumption, and any fruit found on the ground should be avoided due to potential contamination. Health chiefs also specifically advise against consuming raw or partially fermented date palm sap, which poses a significant risk, and recommend avoiding close contact with anyone known to be infected.

Symptoms of Nipah typically begin suddenly, resembling the flu, with fever, headache, muscle aches, vomiting, and a sore throat. In some cases, this progresses to encephalitis or meningitis, usually developing three to 21 days after initial illness, and can be fatal without intensive supportive care. This progression to brain inflammation is considered a hallmark of Nipah infection and is associated with its high mortality rate. The incubation period is usually four to 14 days, though it can extend up to 45 days in rare instances. There have also been reports of relapse in a small number of cases.

Human outbreaks of Nipah virus have so far been confined to South and South-East Asia. The latest outbreak in India's West Bengal region prompted some countries to reintroduce public health measures akin to those used during the Covid-19 pandemic, including tightened airport screenings. This specific outbreak was linked to a private hospital in West Bengal, where at least five healthcare workers were infected. As a precautionary measure, around 110 people who had contact with infected patients have been quarantined. The World Health Organization (WHO) has stated that based on available information, the risk of further spread beyond India's borders is considered low, noting India's capacity to contain such outbreaks. However, the exact source of infection is not yet fully understood, and given the known reservoir of Nipah virus in bat populations across parts of India and Bangladesh, public awareness of risk factors like date palm sap consumption needs reinforcement.

In response to the new cases, several Asian countries have elevated their alert levels and implemented health screening protocols. Thailand's Ministry of Public Health has started screening passengers arriving from West Bengal at major airports for fever and other Nipah symptoms, issuing 'beware' cards with guidance for travelers who become ill. Phuket International Airport has reportedly increased cleaning, and Nepal has also raised its alert levels.