Synchronous shedding of multiple bat paramyxoviruses coincides with peak periods of Hendra virus spillover

Abstract

Within host-parasite communities, viral co-circulation and co-infections of hosts are the norm, yet studies of significant emerging zoonoses tend to focus on a single parasite species within the host. Using a multiplexed paramyxovirus bead-based PCR on urine samples from Australian flying foxes, we show that multi-viral shedding from flying fox populations is common. We detected up to nine bat paramyxoviruses shed synchronously. Multi-viral shedding infrequently coalesced into an extreme, brief and spatially restricted shedding pulse, coinciding with peak spillover of Hendra virus, an emerging fatal zoonotic pathogen of high interest. Such extreme pulses of multi-viral shedding could easily be missed during routine surveillance yet have potentially serious consequences for spillover of novel pathogens to humans and domestic animal hosts. We also detected co-occurrence patterns suggestive of the presence of interactions among viruses, such as facilitation and cross-immunity. We propose that multiple viruses may be interacting, influencing the shedding and spillover of zoonotic pathogens. Understanding these interactions in the context of broader scale drivers, such as habitat loss, may help predict shedding pulses of Hendra virus and other fatal zoonoses.

Viral Diversity of Microbats within the South West Botanical Province of Western Australia

“…Since temporal fluctuation of viral load has been documented in virus surveillance of north American and European microbats [96,97] as well as Hendra shedding in Australian peteropid bats [22,98], longitudinal studies would be required to fully understand the viral shedding and viral-host associations observed here. Furthermore, evidence of higher viral loads as indicators of individual and population scale stress [10] provides a good example of how long-term monitoring of viral prevalence can act as an indicator of environmental pressure on bat communities, particularly with regards to climate change where habitat contracture and distributional shifts may bring together populations harbouring novel viral strains.…”

Parasite associations predict infection risk: incorporating co-infections in predictive models for neglected tropical diseases

“…Importantly, datasets such as the one we used here are commonly generated by many multipathogen surveillance and multi-species monitoring programmes, and so our method can be easily applied to a variety of contexts. Indeed, other critical examples of our methodology have already demonstrated that viral co-infections provide insights into the timing of Hendra virus emergence events [54] and that the compositions of avian blood parasite communities, marshland arthropod communities and wildlife microbiome profiles are the products of complex factors including biotic associations and environmental variation [33,55]. However, a drawback of the CRF approach is that prediction of infection risk for unsampled areas is challenging due to the requirement that at least some parasite presence-absence information needs to be available for the unsampled area.…”

Seroprevalence of three paramyxoviruses; Hendra virus, Tioman virus, Cedar virus and a rhabdovirus, Australian bat lyssavirus, in a range expanding fruit bat, the Grey-headed flying fox (Pteropus poliocephalus)

“…There is evidence to suggest that two species, namely the Black flying fox (Pteropus alecto) and the Spectacled flying fox (P. conspicillatus), play the most active role in the transmission of Hendra virus to horses [38]. Hendra virus is shed in the urine, an important vehicle for transmission in Black flying foxes [10,[38][39], and the virus has been detected in Grey-headed flying fox uterine fluid which provides evidence for possible transmission at birthing period which lasts from late September to early December [40] in this species [41,42].…”