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Caption:Nipah virus remains a high-priority pathogen with fatality rates upto 75 percent and no specific treatments available.
ISLAMABAD: The Nipah virus has re-emerged as a global health concernfollowing confirmation of cases in India in late 2025, prompting severalAsian countries including Thailand, Malaysia, Singapore, Hong Kong, andPakistan to implement enhanced airport screenings for travelers fromaffected regions. This zoonotic pathogen, first identified in 1999 duringan outbreak in Malaysia, spreads primarily from fruit bats and carries acase fatality rate estimated between 40 and 75 percent, depending onoutbreak conditions and healthcare access. With no licensed vaccine orspecific antiviral treatment available, supportive care remains the onlyoption for infected individuals, underscoring the urgency for acceleratedresearch into preventive measures.
The virus belongs to the Paramyxoviridae family, genus Henipavirus, andfeatures a non-segmented negative-sense single-stranded RNA genome. Fruitbats of the Pteropus genus, commonly known as flying foxes, serve as thenatural reservoir, shedding the virus in urine, saliva, and otherexcretions without apparent illness. Spillover to humans occurs throughdirect contact with infected bats, consumption of contaminated food such asraw date palm sap in Bangladesh or fallen fruits in other areas, orexposure to intermediate hosts like pigs, as seen in the original Malaysianoutbreak. Human-to-human transmission has been documented, particularly inhealthcare settings or close household contacts, amplifying risks duringoutbreaks.
Recent developments highlight ongoing challenges, with India reportingsporadic cases almost annually since 2018, predominantly in Kerala but alsoin West Bengal. In late December 2025, two healthcare workers in WestBengal tested positive, leading to quarantine and testing of nearly 200contacts, all negative. Earlier in 2025, Kerala recorded four casesincluding two deaths between May and July. Globally, as of December 2025,approximately 750 confirmed infections and 415 deaths have been documented,with Bangladesh accounting for the highest proportion due to seasonalpatterns linked to date palm sap harvesting from November to March. TheWorld Health Organization classifies Nipah as a priority pathogen requiringurgent research owing to its high lethality, potential for human-to-humanspread, and absence of countermeasures.
Symptoms typically appear after an incubation period of 4 to 14 days,though some reports indicate dormancy up to 45 days in rare instances.Initial signs include fever, headache, muscle pain, vomiting, and sorethroat, progressing rapidly to severe respiratory distress or encephalitischaracterized by convulsions, disorientation, and coma. Survivors oftenface long-term neurological sequelae, such as persistent deficits in motorfunction or cognition, affecting up to 26 percent of cases in someanalyses. The high fatality stems from the virus’s ability to causewidespread inflammation in the brain and lungs, with median case fatalityrates around 69 percent in reviewed clinical data.
Transmission dynamics vary by region. In Bangladesh and parts of India,contaminated date palm sap remains a primary vehicle, as bats urinate orlick collecting vessels during nocturnal foraging. In Malaysia’s 1998-1999outbreak, pigs amplified transmission before culling contained it, causingsignificant economic losses. Person-to-person spread occurs via respiratorydroplets or close contact with bodily fluids, though efficiency remainslower than highly contagious viruses like measles. Preventive strategiesfocus on avoiding bat-contaminated foods, using protective barriers on sapcollection, rigorous hygiene in pig farming, and infection control inhospitals.
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Despite the grim outlook, research progress offers cautious optimism. Noapproved vaccine or treatment exists as of early 2026, but severalcandidates advance through clinical stages. The University of Oxford’sChAdOx1-based vaccine, akin to its COVID-19 platform, initiated Phase IItrials in Bangladesh in December 2025, funded by CEPI and partners. Anothercandidate from Public Health Vaccines targets mid-stage testing in outbreakhotspots. Experimental therapies, including monoclonal antibodies, fusioninhibitors, and repurposed antivirals like remdesivir used in recent Indiancases, undergo evaluation. The WHO’s Research and Development Blueprintemphasizes accelerated development of diagnostics, therapeutics, andvaccines by 2030 to counter this epidemic threat.
Outbreaks impose substantial burdens beyond mortality, straining healthcaresystems and economies in endemic areas. Rapid detection through RT-PCR,contact tracing, and isolation have contained recent Indian incidentseffectively, as in West Bengal where no secondary cases emerged.International collaboration remains vital, with bodies like the Coalitionfor Epidemic Preparedness Innovations supporting trials in high-risksettings. Public awareness campaigns in schools and communities,particularly in Bangladesh, educate on avoidance of risky foods andbehaviors.
The persistence of Nipah underscores the need for sustained investment inzoonotic disease surveillance and One Health approaches integrating animal,human, and environmental health. As climate and habitat changes potentiallyincrease bat-human interfaces, vigilance against this deadly virus mustintensify to prevent larger epidemics.
Source: https://www.who.int/health-topics/nipah-virus-infection
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