The World Health Organization (WHO) on 7/2 confirmed a Nipah virus death in Bangladesh. A woman in her 40s died a week after developing fever and convulsions due to Nipah virus infection. An epidemiological investigation showed she had not traveled abroad before falling ill but had consumed fresh date palm sap. This is a common local practice and also the primary transmission route for the Nipah virus.
Previously, two healthcare workers in West Bengal state, India, were also confirmed to have Nipah virus. Epidemiological investigation results pointed to two hypotheses for the source of infection, including the possibility that fresh date palm sap, a drink consumed by a nurse at a wedding near the India-Bangladesh border, was contaminated with secretions from fruit bats.
This is not an isolated incident but the latest link in the transmission chain of Nipah virus, one of the world's most dangerous pathogens, which is transforming a traditional South Asian beverage into a "deadly cocktail".
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A sap collector places a collection pot at the base of a date palm tree in Sitakunda district, Chattogram province, Bangladesh. Photo: TBS
The infection begins with a centuries-old manual harvesting process. In rural areas of Bangladesh and India, people typically cut the bark of date palm trees and hang ceramic pots overnight to collect the sweet sap. However, the stillness of the night turns these sap pots into ideal destinations for fruit bats of the Pteropus genus, the natural hosts of Nipah virus. Field studies using infrared cameras by the Bangladesh Institute of Epidemiology, Disease Control and Research (IEDCR) have captured haunting footage: bats perching directly on the pot rims, licking the sap oozing from the tree trunk. During this "night feast", they inadvertently excrete urine and saliva containing the virus directly into human food sources.
Professor Stephen Luby, an epidemiologist at Stanford University, described this mechanism as a biological highway in a 2018 Stanford Report interview. He stated that Nipah virus does not harm bats, but when "hitchhiking" through fresh date palm sap, it finds an ideal environment to survive before entering the human body. The virus's persistent survival outside a host is explained by specific chemical and environmental characteristics. According to data from the US National Library of Medicine (NIH), date palm sap has a pH of about 7,2 – a neutral environment almost identical to body fluids, which helps protect the virus's structure. Additionally, the sap harvesting season coincides with winter in South Asia, where temperatures range from 15 to 28 degrees C. This chill inadvertently acts as a "refrigeration unit", extending the virus's lifespan in bat secretions mixed with the tree sap.
The real danger erupts when date palm sap is consumed fresh, without heat treatment (Pasteurization). Unlike the process of cooking sap into gur, which kills pathogens, drinking fresh sap allows Nipah virus to directly attack the respiratory and central nervous systems. Nipah is classified by the WHO and Vietnam's Ministry of Health as a particularly dangerous infectious disease due to its ability to cause acute encephalitis, rapid respiratory failure, and permanent neurological sequelae in about 20% of survivors. The mortality rate of this disease is alarmingly high. According to statistics from ReliefWeb, part of the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), since 2001, Bangladesh has recorded 348 cases with 250 deaths, equating to a mortality rate of 72%. More concerning, nearly half of these infections (162 cases) were directly linked to the consumption of fresh or fermented date palm sap.
The history of Nipah virus is a story of medical and economic shocks. First appearing in 1999 in Malaysia and Singapore, the outbreak claimed the lives of over 100 people and forced authorities to cull over one million pigs, causing immense economic damage. Since then, Nipah has become a "recurring specter" in South Asia, especially Bangladesh and India, with outbreaks occurring almost yearly during the sap harvesting season (december to april). Not only does it transmit from animals to humans, but the virus also has the potential for direct human-to-human transmission (accounting for 29% of cases in Bangladesh), turning each small outbreak into a potential pandemic risk.
In the absence of globally approved antiviral drugs or specific vaccines, and with treatment limited to supportive care, the only "shield" currently available involves physical prevention measures and behavioral changes. Epidemiological experts recommend implementing "bamboo skirts" or similar covering techniques – using bamboo nets or nylon to cover sap collection areas to prevent bats from accessing them. However, the most thorough solution remains the principle of "cooking food thoroughly and boiling water". Boiling the sap before drinking it completely destroys the virus structure, which is sensitive to high temperatures.
Immediately after India confirmed the infections, many Asian countries and territories proactively activated their epidemic prevention systems. Hong Kong, Malaysia, Singapore, Thailand, and Vietnam simultaneously tightened medical screening procedures at air borders to prevent external infiltration risks. Vietnam has not recorded any infections to date. On 27/1, Vietnam's Ministry of Health called for intensified surveillance at borders and in communities, advising people not to eat fruits bitten by bats or birds and to avoid drinking raw palm or coconut sap.
Binh Minh (NIH, WHO, CDC)
