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The island nation of Madagascar is home to three endemic species of Old World fruit bat in the family Pteropodidae: Pteropus rufus , Eidolon dupreanum , and Rousettus madagascariensis , all three of which are IUCN Red Listed under some category of threat. Delineation of seasonal limits in the reproductive calendar for threatened mammals can inform conservation efforts by clarifying parameters used in population viability models, as well as elucidate understanding of the mechanisms underpinning pathogen persistence in host populations. Here, we define the seasonal limits of a staggered annual birth pulse across the three species of endemic Madagascar fruit bat, known reservoirs for viruses of high zoonotic potential. Our field studies indicate that this annual birth pulse takes place in September/October for P. rufus , November for E. dupreanum , and December for R. madagascariensis in central-eastern Madagascar where the bulk of our research was concentrated. Juvenile development periods vary across the three Malagasy pteropodids, resulting in near-synchronous weaning of pups for all species in late January–February at the height of the fruiting season for this region. We here document the size range in morphological traits for the three Malagasy fruit bat species, with P. rufus and E. dupreanum among the larger of pteropodids globally and R. madagascariensis among the smaller. All three species demonstrate subtle sexual dimorphism with males being larger than females. We explore seasonal variation in adult body condition by comparing observed body mass with body mass predicted by forearm length, demonstrating that pregnant females add weight during staggered gestation periods and males lose weight during the nutritionally deficit Malagasy winter. Finally, we quantify forearm, tibia, and ear length growth rates in juvenile bats, demonstrating both faster growth and more protracted development times for P. rufus as compared with E. dupreanum and R. madagascariensis. The longer development period for the already-threatened P. rufus further undermines the conservation status of this species as human hunting is particularly detrimental to population viability during reproductive periods. Our work highlights the importance of longitudinal field studies in collecting critical data for mammalian conservation efforts and human public health alike. [ABSTRACT FROM AUTHOR]

The genus Henipavirus (family Paramyxoviridae) currently comprises seven viruses, four of which have demonstrated prior evidence of zoonotic capacity. These include the biosafety level 4 agents Hendra (HeV) and Nipah (NiV) viruses, which circulate naturally in pteropodid fruit bats. Here, we describe and characterize Angavokely virus (AngV), a divergent henipavirus identified in urine samples from wild, Madagascar fruit bats. We report the nearly complete 16,740-nucleotide genome of AngV, which encodes the six major henipavirus structural proteins (nucleocapsid, phosphoprotein, matrix, fusion, glycoprotein, and L polymerase). Within the phosphoprotein (P) gene, we identify an alternative start codon encoding the AngV C protein and a putative mRNA editing site where the insertion of one or two guanine residues encodes, respectively, additional V and W proteins. In other paramyxovirus systems, C, V, and W are accessory proteins involved in antagonism of host immune responses during infection. Phylogenetic analysis suggests that AngV is ancestral to all four previously described bat henipaviruses--HeV, NiV, Cedar virus (CedV), and Ghanaian bat virus (GhV)--but evolved more recently than rodent- and shrew-derived henipaviruses, Mojiang (MojV), Gamak (GAKV), and Daeryong (DARV) viruses. Predictive structure-based alignments suggest that AngV is unlikely to bind ephrin receptors, which mediate cell entry for all other known bat henipaviruses. Identification of the AngV receptor is needed to clarify the virus's potential host range. The presence of V and W proteins in the AngV genome suggest that the virus could be pathogenic following zoonotic spillover. [ABSTRACT FROM AUTHOR]

Bats (order Chiroptera) are hosts for highly virulent zoonotic pathogens. Many bats demonstrate seasonally varying antiviral responses, including antibody responses which have been observed to peak during the nutritionally depleted dry-season and female gestation periods, suggesting some impact of resource deficits on bat virus immunity. Given the frequent overlap in these energetically demanding periods, it is likely that endocrinological changes associated with pregnancy might partially explain the aforementioned pattern in antibody dynamics. Regardless, we know little about the seasonality of reproduction in many fruit bat species, despite the importance of reproductive biology to informing conservation management (e.g. population viability) and disease dynamics. Here, we aimed to elucidate the reproductive biology of three species of endemic fruit bat native to the island of Madagascar: Pteropus rufus, Eidolon dupreanum, and Rousettus madagascarensis. To do so, we leveraged plasma samples collected in part with a longitudinal field study, from 2018 to 2020. We adapted three standard reproductive assays previously validated in humans to quantify seasonal changes in reproductive hormones for bats and applied a mixture model approach to determine hormone cutoffs for pregnancy. As expected, we found that pregnant females showed the highest levels of estradiol and progesterone and adult males the highest levels of testosterone. Additionally, female P. rufus and R. madagascariensis showed clear seasonality in reproduction with peaks in estradiol and progesterone in August and October, respectively. Seasonality was less clearly discernible in the female E. dupreanum and male data. In general, we found that the commercially available assays were successful in quantifying endocrinological hormones for bats; when paired with histological embryo sections or field data, these offer a powerful tool to elucidate bat reproductive calendars.

Bats are natural reservoirs for both Alpha - and Betacoronaviruses and the hypothesized original hosts of five of seven known zoonotic coronaviruses. To date, the vast majority of bat coronavirus research has been concentrated in Asia, though coronaviruses are globally distributed; indeed, SARS-CoV and SARS-CoV-2-related Betacoronaviruses in the subgenus Sarbecovirus have been identified circulating in Rhinolophid bats in both Africa and Europe, despite the relative dearth of surveillance in these regions. As part of a long-term study examining the dynamics of potentially zoonotic viruses in three species of endemic Madagascar fruit bat ( Pteropus rufus, Eidolon dupreanum, Rousettus madagascariensis ), we carried out metagenomic Next Generation Sequencing (mNGS) on urine, throat, and fecal samples obtained from wild-caught individuals. We report detection of RNA derived from Betacoronavirus subgenus Nobecovirus in fecal samples from all three species and describe full genome sequences of novel Nobecoviruses in P. rufus and R. madagascariensis . Phylogenetic analysis indicates the existence of five distinct Nobecovirus clades, one of which is defined by the highly divergent ancestral sequence reported here from P. rufus bats. Madagascar Nobecoviruses derived from P. rufus and R. madagascariensis demonstrate, respectively, Asian and African phylogeographic origins, mirroring those of their fruit bat hosts. Bootscan recombination analysis indicates significant selection has taken place in the spike, nucleocapsid, and NS7 accessory protein regions of the genome for viruses derived from both bat hosts. Madagascar offers a unique phylogeographic nexus of bats and viruses with both Asian and African phylogeographic origins, providing opportunities for unprecedented mixing of viral groups and, potentially, recombination. As fruit bats are handled and consumed widely across Madagascar for subsistence, understanding the landscape of potentially zoonotic coronavirus circulation is essential for mitigation of future zoonotic threats., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kettenburg, Kistler, Ranaivoson, Ahyong, Andrianiaina, Andry, DeRisi, Gentles, Raharinosy, Randriambolamanantsoa, Ravelomanantsoa, Tato, Dussart, Heraud and Brook.)