Identification of Pteropine Orthoreoviruses in Bangladesh
Infectious disease researchers have identified Pteropine orthoreoviruses (PRVs) as the cause of previously unexplained illness in five patients in Bangladesh, one of whom died. This marks the first documented detection of a bat-origin orthoreovirus in human cases presenting with acute respiratory illness and encephalitis in the country. The findings were published in the journal Emerging Infectious Diseases.
Link to Date-Palm Sap and Bat Reservoirs
All five patients reported recent consumption of raw date-palm sap, which is also consumed by bats during winter months and is a known vector for Nipah virus infections in Bangladesh. Bats are natural reservoirs for numerous known and novel zoonotic viruses, including rabies, Nipah, Hendra, Marburg, and SARS1. Nischay Mishra, PhD, associate professor of epidemiology at Columbia University Mailman School of Public Health and senior author of the study, stated that these findings indicate the risk of zoonotic spillover associated with raw date palm sap consumption extends beyond Nipah virus. He emphasized the importance of broad-spectrum surveillance programs to identify and mitigate public health risks from emerging bat-borne viruses.
Investigation Methodology
The five patients were hospitalized between 2022 and 2023 with symptoms similar to Nipah infections, including fever, vomiting, headache, fatigue, increased salivation, and respiratory and neurological complications. However, they tested negative for Nipah virus. Researchers performed high-throughput agnostic viral sequencing using the VirCapSeq-VERT system on biological samples from these five patients, alongside samples from over 130 other patients presenting with Nipah-like symptoms between 2006 and 2022. These samples were collected 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 the U.S. Centers for Disease Control and Prevention (CDC).
VirCapSeq-VERT, developed at the Center for Infection and Immunity (CII), screens for viral infections of vertebrate origin. The technology is described as sensitive as polymerase chain reaction (PCR) assays, while allowing simultaneous testing for multiple viruses and providing near-complete genome sequences. The study also confirmed the presence of the infectious virus through culturing.
Findings and Ongoing Research
All five patients experienced severe disease. While PRV infections reported in neighboring countries have often been milder, this suggests that less severe cases in Bangladesh may be underrecognized. Tahmina Shirin, PhD, Director of the IEDCR and the National Influenza Centre (NIC) in Bangladesh, noted that PRV infection represents a newly identified cause of zoonotic spillover resulting in respiratory and neurological complications following raw date palm sap consumption, similar to Nipah virus.
In a separate, more recent study supported by the U.S. Department of Agriculture, Mishra and colleagues identified genetically similar Pteropine orthoreoviruses in bats captured near the five human cases in the Padma River Basin. Ariful Islam, a bat-borne disease ecologist and epidemiologist at Charles Sturt University, Australia, and co-first author of the study, commented that this research provides evidence linking bat reservoirs to human infection. Research is currently underway to understand 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.
Collaborations and Technology Application
The VirCapSeq-VERT technology has been previously used to identify viral threats to transplant patients, neurologic manifestations in an infant with COVID-19, enterovirus infection as a cause for a rare neurological condition, and the origins of chikungunya in Brazil. The technology has also obtained regulatory approval for clinical use.
The study's co-first author is Sharmin Sultana, assistant professor of Virology and Senior Scientific Officer at IEDCR. Additional authors include James Ng, Sunil Kumar Dubey, Cheng Guo, and W. Ian Lipkin of the CII; Manjur Hossain Khan at IEDCR; Mohammed Ziaur Rahman and Moinuddin Satter at icddr,b; Joel M. Montgomery at the CDC; and Lisa Hensley at the U.S. Department of Agriculture. The research received funding from the United States Department of Agriculture.