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

Mendenhall, Ian H.; Skiles, Maggie M.; Neves, Erica Sena; Borthwick, Sophie A.; Low, Dolyce H.W.; Liang, Benjamin; Lee, Benjamin P.Y.-H.; Su, Yvonne C.F.; Smith, Gavin J.D.

Interestingly, we revealed phylogenetically diverse astroviruses among E. spelaea bats, with at least two distinctive groups (Clade 1 and 2). Clade 1 (BS = 69%) is further composed of three smaller sub-clades (designated as a-c). Clade 1a (nucleotide identity 60.8-99.2%) includes 4 E. spelaea astroviruses from Singapore (BS = 100%) whereas the other comprises one Pteropus giganteus astrovirus from Bangladesh and a Rousettus sp. astrovirus from Laos. Clade 1b (BS = 65%; nucleotide identity 64.8-100%) is composed of Rousettus astroviruses from Laos. Clade 1c (nucleotide identity: 66.8-99.2%) includes astroviruses from E. spelaea (Singapore) and Rousettus leschenaultia (Laos). Both Singapore E. spelaea astrovirus clades were collected in the same sampling period. Clade 2 (BS = 51%; nucleotide identity 65.3-99.2%) contains two E. spelaea astroviruses, one Rhinolophus astrovirus and numerous Rousettus astroviruses, all from Laos. This suggests that E. spelaea astroviruses from Singapore are closely related to those of Laos Rousettus spp., yet are distantly related to Laos E. spelaea astroviruses. Clade 2 further displays the close phylogenetic relationship between E. spelaea and Rousettus spp. astroviruses (BS = 61%), all occurring in Laos. It is likely that the co-roosting of these bat species facilitated the interspecies virus transmission.