Co-circulation of distinct genetic lineages of astroviruses in turkeys and guinea fowl

Viruses belonging to the genus Astrovirus have been increasingly associated with enteritis in mammalian and avian species, including turkeys. More recently, astroviruses have also been detected in diseased guinea fowl. In turkeys, two genetically distinct types of astrovirus have been reported, namely turkey astrovirus 1 and 2 (TAstV1 and TAstV2). The prevalence and the pathogenesis of astrovirus infections in this species is currently unknown, with the exception of data generated in the USA. In the present report, we have demonstrated the co-circulation of distinct genetic lineages of astroviruses infecting turkeys and guinea fowl. The predominant lineage infecting turkeys is genetically related to the American TAstV2, but genetic variability within this lineage was demonstrated. Other isolates appeared to be either TastV1-related or unrelated to any other known isolate. Astroviruses infecting guinea fowl were more closely related to TAstV2, and interspecies transmissions between turkeys and guinea fowl is suggested as a possible mechanism by which these viruses may have evolved, based on the genetic data available. This investigation provides genetic and epidemiological information contributing to a better understanding of enteric viral infections in turkeys and guinea fowl.