Infectious disease experts have identified Pteropine orthoreoviruses (PRVs), a type of virus carried by bats, as the cause of previously unexplained illnesses in five people from Bangladesh. One of the patients died after developing severe symptoms. This is the first confirmed detection of bat-origin orthoreovirus in human cases involving acute respiratory illness and encephalitis in Bangladesh. The findings were published in Emerging Infectious Diseases.
All five individuals had recently consumed raw date-palm sap, which is also consumed by bats during winter and is a known route for Nipah virus transmission in Bangladesh. Bats are recognized as reservoirs for various zoonotic viruses such as rabies, Nipah, Hendra, Marburg, and SARS1.
Nischay Mishra, PhD, associate professor at Columbia University Mailman School of Public Health and senior author of the study, said: "Our findings highlight that the risk of zoonotic spillover associated with raw date palm sap consumption extends beyond Nipah virus." He added: "He also underscores the importance of broad-spectrum surveillance programs to identify and mitigate public health risks from emerging bat-borne viruses."
Between 2022 and 2023, these patients were hospitalized with symptoms similar to those caused by Nipah virus—including fever, vomiting, headache, fatigue, increased salivation, respiratory problems, and neurological complications—but they tested negative for Nipah. Researchers used high-throughput viral sequencing with CII's VirCapSeq-VERT system on samples from these patients and over 130 others who showed similar symptoms between 2006 and 2022. This work was part of an ongoing surveillance program led by Bangladeshi health authorities alongside international partners.
The VirCapSeq-VERT technology allows simultaneous screening for thousands of vertebrate-origin viruses with sensitivity comparable to PCR tests while delivering near-complete genome sequences. The presence of infectious PRV was confirmed through culturing methods. While all five cases involved severe illness in Bangladesh, milder PRV infections have been reported elsewhere in neighboring countries; researchers note that less severe cases may be underrecognized locally.
Tahmina Shirin, PhD, Director at the Institute of Epidemiology, Disease Control and Research (IEDCR) and National Influenza Centre (NIC) in Bangladesh said: "A new addition of zoonotic spillover causes respiratory and neurological complications following consumption of raw date palm sap next to Nipah virus infection."
A related recent study supported by the U.S. Department of Agriculture found genetically similar PRVs in bats captured near where the human cases occurred along the Padma River Basin.
Ariful Islam from Charles Sturt University in Australia stated: "This [research] provides critical evidence linking bat reservoirs to human infection. We are now working to understand the spillover mechanisms from bats to humans and domestic animals, as well as the broader ecology of emerging bat-borne viruses in communities along the Padma River Basin."
Previously developed at CII for other viral threats including COVID-19-related neurological conditions and chikungunya tracing efforts in Brazil, VirCapSeq-VERT has regulatory approval for clinical use beyond its research applications.
Sharmin Sultana at IEDCR served as co-first author on this study along with contributions from scientists based at Columbia University’s Center for Infection and Immunity (CII), IEDCR Bangladesh; icddr,b Bangladesh; CDC’s National Center for Emerging and Zoonotic Infectious Diseases; and the U.S. Department of Agriculture’s Zoonotic and Emerging Disease Research Unit.
Funding came through United States Department of Agriculture agreements with Columbia University.
