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.

This is the first report of bat astroviruses from Singapore and the first report of astrovirus infection in Rhinolophus lepidus. 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. (7.2%) [44] . For longitudinal monitoring, the volume of samples may hinder processing, making pooling a feasible option. However, if the number of positive samples is low, the sensitivity of the test may present false negatives and if all the pools are positive, as occurred on three sampling occasions in this study, one is unable to estimate individual prevalence. In cases where we screened individual samples, the individual detection rate was greater than the estimated prevalence. This may result from the pooling of the samples lowering the relative quantity of virus in comparison to the background material.