Nipah reached a Bengal hospital. Two nurses infected, 190 contacts tested negative

On January 26 the National IHR Focal Point for India notified the World Health Organization of two laboratory-confirmed Nipah virus infections in West Bengal State [s1]. Both patients are health care workers at the same private hospital in Barasat, in North 24 Parganas district [s1].

Two cases is a small number. Nipah is the reason it is not being treated as one.

What is known

The first case is a female nurse, the second a male nurse; both are between 20 and 30 years old and from Barasat [s1]. Both developed symptoms typical of severe Nipah infection in late December 2025 and were admitted to hospital in early January 2026 [s1].

Preliminary testing suggested Nipah infection, and the National Institute of Virology in Pune confirmed both cases on January 13 using RT-PCR and ELISA testing [s1]. As of January 21, one case remained on mechanical ventilation under critical care; the other, who experienced severe neurological illness, had shown clinical improvement [s1].

Indian health authorities identified and tested more than 190 contacts, including health and care workers and community contacts, with support from a mobile BSL-3 laboratory deployed by the National Institute of Virology, Pune [s1]. All contact samples tested negative [s1]. On January 27 the Indian National Centre for Disease Control announced that no further confirmed cases had been detected in West Bengal from December 2025 to date [s1].

Investigations into the source of exposure are ongoing, with enhanced surveillance and infection prevention and control measures in place [s1].

Why two cases in health workers matters

Nipah's case fatality rate is estimated at 40 to 75 percent [s2]. There are no approved drugs or vaccines; treatment consists of early, intensive supportive care, which can improve survival [s2]. Among people who recover, long-term neurological conditions have been reported in approximately one in five [s2].

The virus spreads to people from infected animals — fruit bats of the Pteropodidae family are the natural host — or through contaminated food such as raw date palm juice, and it can also spread directly between people [s2]. Human-to-human transmission has been documented in previous outbreaks, mostly in health care settings and among family members and caregivers, through close contact with bodily fluids [s1]. In health facilities, the risk rises in crowded, poorly ventilated environments where infection prevention and control measures are inadequately implemented [s2].

That is the specific concern here. Both confirmed cases are hospital staff. The source of their exposure has not been established. A hospital is where Nipah has historically amplified, and it is also where the disease is hardest to recognise early, because the first phase presents non-specifically — fever, headache, confusion, cough — and can delay diagnosis, outbreak detection, and response [s1].

The incubation period runs 3 to 14 days, with rare reports up to 45 days [s2]. That range, combined with more than 190 negative contact tests and no additional confirmed cases as of January 27, is the basis for cautious reassurance rather than an all-clear [s1].

The regional pattern

This is the third Nipah outbreak reported in West Bengal, after Siliguri in 2001 and Nadia district in 2007 [s1]. Kerala has reported multiple outbreaks since 2018 [s1].

WHO notes that the annual number of Nipah cases reported in India has remained relatively low since 2001, with two exceptions: 66 cases in 2001 and 18 in 2018 [s1]. Over the past five years, a dozen confirmed cases were reported in India, all in Kerala State [s1].

Nipah infections were first reported in 1998, and since then have been reported in Bangladesh, India, Malaysia, the Philippines and Singapore [s2]. The virus was first identified during an outbreak among pig farmers in Malaysia in 1998; no new outbreaks have been reported from Malaysia or Singapore since 1999 [s2].

WHO's risk assessment

WHO assesses the public health risk as moderate at the sub-national level, and low at the national, regional and global levels [s1].

The sub-national rating reflects the absence of specific drugs or vaccines and the difficulty of early diagnosis, set against the presence of fruit bats in India and repeated demonstrated spillover from the reservoir into human populations [s1]. The regional rating reflects that there have been no reports of cross-border transmission and that the outbreak remains geographically limited, though the risk persists because of the shared ecological corridor of fruit bats [s1].

WHO does not recommend any travel or trade restrictions based on currently available information [s1].

What to watch

Whether the source investigation identifies a point of exposure. Two nurses at the same hospital could reflect a shared community exposure, an unrecognised index patient, or a transmission event within the facility — and which of those it turns out to be determines what the response needs to address.

Whether the outbreak stays at two cases through the outer bound of the incubation window.

And whether the case still under critical care survives. WHO's most recent status for that patient is dated January 21 [s1].

Nipah is on WHO's Research and Development Blueprint list of priority diseases, and a range of candidate vaccines and therapeutics are at different stages of development [s2]. None is licensed.

This article is informational and is not medical advice.