Seasonal Fluctuations of Astrovirus, But Not Coronavirus Shedding in Bats Inhabiting Human-Modified Tropical Forests

Abstract

Emerging infectious diseases (EIDs) are considered a major threat to global health. Most EIDs appear to result from increased contact between wildlife and humans, especially when humans encroach into formerly pristine habitats. Habitat deterioration may also negatively affect the physiology and health of wildlife species, which may eventually lead to a higher susceptibility to infectious agents and/or increased shedding of the pathogens causing EIDs. Bats are known to host viruses closely related to important EIDs. Here, we tested in a paleotropical forest with ongoing logging and fragmentation, whether habitat disturbance influences the occurrence of astro- and coronaviruses in eight bat species. In contrast to our hypothesis, anthropogenic habitat disturbance was not associated with corona- and astrovirus detection rates in fecal samples. However, we found that bats infected with either astro- or coronaviruses were likely to be coinfected with the respective other virus. Additionally, we identified two more risk factors influencing astrovirus shedding. First, the detection rate of astroviruses was higher at the beginning of the rainy compared to the dry season. Second, there was a trend that individuals with a poor body condition had a higher probability of shedding astroviruses in their feces. The identification of risk factors for increased viral shedding that may potentially result in increased interspecies transmission is important to prevent viral spillovers from bats to other animals, including humans.

Influence of age and body condition on astrovirus infection of bats in Singapore: An evolutionary and epidemiological analysis

“…Previous surveillance efforts have demonstrated variable rates of astrovirus infection from diverse bat species, including those tested here [38]. Astroviruses have been detected from ten other species of Rhinolophus bats in previous studies [39][40][41][42][43]. A recent study in Cambodia and Laos screened six members of the family Pteropodidae and astroviruses were only detected in Eoncyteris spelaea (3.8%) and Rousettus spp.…”

“…We found variable rates of shedding across our sampling period. In Singapore, temperatures are not variable month to month, but there are two monsoon seasons, which may be associated with bat borne virus shedding [43]. A study on Myotis myotis in Germany demonstrated distinct astrovirus amplification peaks that correlated with the formation of a suitable roost size and also a post-parturition period [45].…”

“…In the tropics, where there is lower seasonal variation and an absence of torpor, the reproductive behavior of bats may drive virus persistence [46]. This may not always be the case as astrovirus and coronavirus shedding in Borneo was not associated with reproductive status [43]. We analyzed the astrovirus RdRp sequences from a broad range of hosts including bats and non-human primates [44,47,48].…”

Pathogen spillover during land conversion

“…; Seltmann et al . ). Specifically, nutritional stress after loss of winter nectar sources may drive Hendra virus shedding and spillover from fruit bats (Plowright et al .…”

A Comparative Analysis of Viral Richness and Viral Sharing in Cave-Roosting Bats

“…Increasing evidence supports the assumption that habitat quality and bat health are inherently linked. For example, in paleotropical forests with intense logging and fragmentation, bats with poor body conditions were more likely to shed astroviruses in feces [34]. Seltmann et al [34] speculated that increased susceptibility of individuals to acquire and shed viruses may have resulted from stress-induced immunosuppression.…”