Serological Evidence of Bat-Borne and Shrew-Borne Hantavirus Infections in Humans: A Comparative Study from Thailand, Sri Lanka, and Zambia

This study provides the first evidence of human infection with bat-borne hantaviruses and reveals widespread exposure to both bat- and shrew-borne hantaviruses in human and animal populations across Asia and Africa. Traditionally, hantaviruses were known as rodent-borne pathogens causing severe disease in humans. However, numerous novel viruses have been discovered in shrews, moles, and bats, yet their potential to infect humans remained unclear due to a lack of comprehensive serological tools.

Using a newly developed mixed-antigen screening system based on recombinant nucleocapsid proteins, researchers conducted retrospective serological studies on human samples from Thailand and Sri Lanka, as well as bat samples from Zambia. The method proved highly efficient, reducing the number of test wells required by 80%.

In Thailand, among 143 patients initially suspected of leptospirosis, 4.9% showed confirmed seroconversion to bat-borne hantaviruses (Robina virus, Dakrong virus, and Xuan Son virus). Notably, this rate was significantly higher than the prevalence of classical rodent-borne hantavirus infections (<1.4%) in the same cohort.

In Sri Lanka, screening of 336 human sera (half healthy, half febrile) revealed that 23.2% of febrile patients had antibodies to either bat-borne or shrew-borne hantaviruses, compared to only 1.2% of healthy controls. Reactivity was detected against a wide range of viruses, including Quezon virus, Robina virus, Asama virus, and Thottapalayam virus.

Among 1,764 bats from 11 species in Zambia, overall seroprevalence reached 28.8%, with reactivity to both bat-borne and shrew-borne antigens. Frugivorous bat species showed higher seropositivity than insectivorous ones.

The findings demonstrate that bat-borne and shrew-borne hantaviruses are capable of infecting humans and may represent emerging zoonotic pathogens with a broader geographic distribution than previously recognized. The study underscores the urgent need for expanded surveillance, virus isolation, reservoir identification, and clinical assessment of these novel viruses to inform public health preparedness.