Prevalence and genetic diversity of coronaviruses, astroviruses and paramyxoviruses in wild birds in southeastern Kazakhstan.

Wild birds are natural reservoirs of many emerging viruses, including some zoonoses. Considering that the territory of Kazakhstan is crossed by several bird migration routes, it is important to know pathogenic viruses circulating in migratory birds in this region. Therefore, the aim of this study was to identify the host range, diversity and spatial distribution of avian paramyxoviruses, coronaviruses, and astroviruses in free-ranging wild birds in the southeastern region of Kazakhstan. For this purpose, we collected tracheal and cloacal swabs from 242 wild birds belonging to 51 species and screened them using conventional PCR assays. Overall, 4.1% (10/242) and 2.9% (7/242) of all examined birds tested positive for coronaviruses and astroviruses, respectively. Coronaviruses were found in the orders Pelecaniformes (30%; 3/10), Charadriiformes (30%; 3/10), Columbiformes (20%; 2/10), Anseriformes (10%; 1/10), and Passeriformes (10%; 1/10). All detected strains belonged to the genus Gammacoronavirus. Astroviruses were detected in birds representing the orders Passeriformes (57%; 4/7), Coraciiformes (14%; 1/7), Charadriiformes (14%; 1/7), and Columbiformes (14%; 1/7). Paramyxoviruses were observed in only two birds (0.8%; 2/242). Both strains were closely related to the species APMV-22, which had not been previously detected in Kazakhstan. Phylogenetic analysis of the partial RdRp gene sequences of the virus strains revealed three different clades of astroviruses, two clades of coronaviruses, and one clade of paramyxoviruses. The results of this study provide valuable information on the diversity and spatial distribution of paramyxoviruses, coronaviruses, and astroviruses in wild birds in southeastern Kazakhstan and highlight the importance of further thorough monitoring of wild birds in this region.

Coronaviruses in Bats

This article summarizes current detections of coronaviruses in bats in different geographic regions worldwide, and underlines the potential role of bats as ancestor and reservoir hosts of different coronaviruses. Bats can be found in almost all global habitats with the notable exception of the high arctic and a few isolated oceanic islands. First, we give an overview on the potential role of bats as carriers of zoonotic viruses, underlining the relevance of specific physiological traits of representatives of this mammalian order, that are supporting the transmission of these disease agents. Research in this field was predominantly initiated by the SARS coronavirus event in 2003, and in the meantime, bats are assumed to be the ancestor hosts for numerous alpha and beta coronaviruses. Bat associated coronaviruses have been detected on all continents where bats are distributed. Since the beginning of the COVID-19 pandemic, coronavirus research has again been considerably intensified, leading to a gain of knowledge regarding the interaction between bats and coronaviruses that will be valuable in the management of potential future outbreaks originating from bats. Finally, an outlook is given on research gaps that could be invaluable when dealing with future pandemic events.