Assessing mechanisms for the persistence of RNA viruses in bats using a captive and wild Eidolon helium colonies

About This Grant

PROJECT SUMMARY/ABSTRACT Emerging and re-emerging viruses represent a serious and ongoing threat to human health, and both the frequency and impact of emerging viruses are expected to increase due to factors such as modernization, environmental degradation, and changes in human population density. Many high consequence viruses for humans have recently emerged from stable relationships with bats, but we know very little about these viruses in their natural reservoirs, including their host range, prevalence and various factors that influence virus shedding and spillover risk. A better understanding of these viruses is needed to enable a more predictive and proactive approach for preventing emergence. This proposal seeks to address some of these knowledge gaps through an innovative combination of longitudinal molecular surveillance, highly-multiplexed serology, and whole genome virus sequencing in two nearby colonies (one captive and one wild) of straw-colored fruit bats (Eidolon helvum) in Ghana. E. helvum is a member of the Pteropodidae family, which includes natural hosts for several highly-pathogenic zoonotic viruses, and there are multiple documented interfaces for the transmission of viruses from E. helvum to humans, livestock, and other wild animals throughout its range in sub-Saharan Africa. Studies of viral epidemiology in this species of bat have been enabled by a unique long-term, captive breeding colony at the University of Ghana. Here, we propose to utilize this captive colony of E. helvum to study mechanisms of virus persistence and transmission, which relate directly to the prevalence and magnitude of virus shedding and therefore also to spillover risk. There is mounting evidence that many viruses are capable of establishing persistent infections in bats, characterized by recurrent episodes of virus shedding, which may be triggered by environmental factors. However, existing data lack the resolution needed to directly test this hypothesis, and it is unknown how common such infections are across different virus groups. We will investigate this hypothesis through individual-level longitudinal surveillance of viruses within our unique captive colony of E. helvum, in combination with a multi-pronged analysis comparing the variety and prevalence of viruses between captive and wild populations. First, we will use longitudinal sample collection and broad-range PCR to monitor virus shedding over time (Aim 1). Second, we will use highly-multiplexed serology to obtain an unprecedented view of the viruses infecting E. helvum bats and to identify differences in infection histories between captive and wild animals (Aim 2). Third, we will use whole genome sequencing to examine the evolutionary relationships among viruses shed in the captive colony (with individual-level resolution) and those circulating in wild bats (Aim 3). If chronic infections play an important role in virus persistence in these bats, we expect to see similar types of viruses in both colonies, recurrent shedding of the same viruses, and individual level phylogenetic clustering of viral genomes.