Unexplained respiratory and neurological illnesses in Bangladesh have been identified as Pteropine orthoreoviruses (PRVs)—a group of newly emergent bat-borne viruses.
RT’s Three Key Takeaways:
New zoonotic virus identified – Researchers detected bat-borne Pteropine orthoreoviruses in five Bangladeshi patients with severe respiratory and neurological illness, marking the first confirmed human cases of this virus in Bangladesh and linking it to one fatality.
Raw date-palm sap as a spillover risk – All infected patients had consumed raw date-palm sap, showing that zoonotic transmission from bats via this practice extends beyond Nipah virus to additional emerging pathogens.
Need for broad viral surveillance – Advanced sequencing with VirCapSeq-VERT revealed PRVs that standard testing missed, underscoring the importance of broad-spectrum surveillance to detect underrecognized bat-borne viruses and prevent future outbreaks.
Infectious disease researchers have identified Pteropine orthoreoviruses (PRVs), a group of newly emergent bat-borne viruses, as the culprit for previously unexplained illness in five Bangladeshi patients, one of whom eventually died with unexplained illness. The findings mark the first documented detection of bat-origin orthoreovirus—a kind of double-stranded RNA virus—in human cases of acute respiratory illness and encephalitis in Bangladesh. The study appears in the journal Emerging Infectious Diseases.
All five patients had recently consumed raw date-palm sap—a treat also enjoyed by bats during winter months—and a known vector for Nipah infections in Bangladesh. Bats are the natural reservoir of numerous known and novel zoonotic viruses, including rabies, Nipah, Hendra, Marburg, and SARS1.
“Our findings highlight that the risk of zoonotic spillover associated with raw date palm sap consumption extends beyond Nipah virus,” said Nischay Mishra, PhD, associate professor of epidemiology at the Center for Infection and Immunity, Columbia University Mailman School of Public Health, and senior author of the study. “He also underscores the importance of broad-spectrum surveillance programs to identify and mitigate public health risks from emerging bat-borne viruses.”
Hospitalized between 2022 and 2023, the five patients had presumed Nipah infections but tested negative for Nipah virus despite having similar symptoms, including fever, vomiting, headache, fatigue, increased salivation, respiratory, and neurological complications. In the new study, researchers performed high-throughput agnostic viral sequencing with CII’s VirCapSeq-VERT system using biological samples taken from the five infected patients along with another 130-plus patients presenting with Nipah-like symptoms between 2006 and 2022, as part of a Nipah virus surveillance program established by the Institute of Epidemiology, Disease Control and Research (IEDCR), Bangladesh; International Centre for Diarrheal Disease Research, Bangladesh (icddr,b); and CDC.
Nischay and colleagues used VirCapSeq-VERT, a technology developed at the CII to quickly and efficiently screen for all viral infections of vertebrate origin. VirCapSeq-VERT is as sensitive as the gold-standard polymerase chain reaction (PCR) assays while enabling simultaneous testing for thousands of viruses and providing near-complete genome sequences. This study also confirmed the presence of the infectious virus by culturing the virus. All five patients experienced severe disease, although PRV infections reported elsewhere in neighboring countries have often been milder, suggesting that less severe cases in Bangladesh may be underrecognized.
“A new addition of zoonotic spillover causes respiratory and neurological complications following consumption of raw date palm sap next to Nipah virus infection,” says Tahmina Shirin, PhD, Director, Institute of Epidemiology, Disease Control, and Research (IEDCR), as well as the National Influenza Centre (NIC) in Bangladesh.
In a study conducted more recently that was supported by the U.S. Department of Agriculture, Mishra and colleagues identified the source of infections by identifying genetically similar Pteropine orthoreoviruses in bats captured in proximity to the five human cases near the Padma River Basin (unpublished data).
“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,” says Ariful Islam, bat-borne disease ecologist and epidemiologist at Charles Sturt University, Australia, and co-first author of the study.