Characterization of Experimental Oro-Nasal Inoculation of Seba's Short-Tailed Bats (Carollia perspicillata) with Bat Influenza A Virus H18N11.

Marco Gorka,Reiner Ulrich,Martin Schwemmle,Jan Schinköthe,Donata Hoffmann,Martin Beer,Kevin Ciminski

doi:10.3390/v12020232

Abstract

In 2012 and 2013, the genomic sequences of two novel influenza A virus (IAV) subtypes, designated H17N10 and H18N11, were identified via next-generation sequencing in the feces of the little yellow-shouldered fruit bat (Sturnira lilium) and the flat-faced fruit-eating bat (Artibeus planirostris), respectively. The pathogenesis caused by these viruses in their respective host species is currently insufficiently understood, which is primarily due to the inability to obtain and keep these bat species under appropriate environmental and biosafety conditions. Seba’s short-tailed bats (Carollia perspicillata), in contrast, are close relatives and a natural H18N11 reservoir species, with the advantage of established animal husbandry conditions in academic research. To study viral pathogenesis in more detail, we here oro-nasally inoculated Seba’s short-tailed bats with the bat IAV H18N11 subtype. Following inoculation, bats appeared clinically healthy, but the histologic examination of tissues revealed a mild necrotizing rhinitis. Consistently, IAV-matrix protein and H18-RNA positive cells were seen in lesioned respiratory and olfactory nasal epithelia, as well as in intestinal tissues. A RT-qPCR analysis confirmed viral replication in the conchae and intestines as well as the presence of viral RNA in the excreted feces, without horizontal transmission to naïve contact animals. Moreover, all inoculated animals seroconverted with low titers of neutralizing antibodies.

Highlights

Influenza A viruses (IAVs) originate from aquatic waterfowl and are important animal pathogens and zoonotic agents, circulating in a broad range of avian and mammalian species [1]
A recent study reported that H18N11 replicates especially in the lamina propria of the small intestine and the follicle-associated epithelium of the jejunal Peyer’s patches of infected Jamaican fruit bats [18]
Seba’s short-tailed bats (Carollia perspicillata) at different time points after infection, animals were split into three groups: Group A consisted of four bats sacrificed at 4 dpi, from which two were initially inoculated and two others that remained naïve in order to monitor viral transmission (Figure 1A)

Summary

Introduction

Influenza A viruses (IAVs) originate from aquatic waterfowl and are important animal pathogens and zoonotic agents, circulating in a broad range of avian and mammalian species [1]. Bats (order Chiroptera) are well known as an important reservoir for various zoonotic pathogens like lyssa-, henipa- or filoviruses; until recently they were not considered to harbor IAVs [6,7]. This view changed in 2012 and 2013, when two novel IAVs genomes were identified by next-generation. Viruses 2020, 12, 232 sequencing in the feces of the little yellow-shouldered fruit bat (Sturnira lilium) from Guatemala and the flat-faced fruit-eating bat (Artibeus planirostris) from Peru, subsequently designated as H17N10 and H18N11 [8,9] These bat-derived IAVs exhibited unprecedented characteristics, since both subtypes express hemagglutinin (HA) and neuraminidase (NA) proteins unable to bind sialic acids residues [10,11,12,13,14,15]. The tropism of H18N11 and the pathogenesis in its natural reservoir is insufficiently understood, as there is currently only one study available focusing on the Neotropical

Methods

Results

Conclusion