Evolving Rotaviruses, Interspecies Transmission and Zoonoses

Abstract

Evolutionary biology has become one of the imperative determinants explaining the origin of several viruses which were either identified decades back or are recognized lately using metagenomic approaches. Several notifiable emerging viruses like influenza, Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), Ebola, Hendra, Nipah and Zika viruses have become the leading causes of epidemics and losses thereto in both human and animals. The sufferings are higher due to gastroenteritis causing viruses including Astrovirus, Calicivirus, Enterovirus, Kobuvirus Picobirnavirus, Sapelovirus, Teschovirus, and many more. Notably, the majority of the emerging viruses enclose RNA genome and these are more prone for insertions/mutation in their genome, leading to evolving viral variants. Rapidity in viral evolution becomes a big hitch in the development process of successful vaccines or antiviral. The prominent gastroenteric virus is rotavirus, which is a double-stranded RNA virus with a segmented nature of genome enabling higher reassortment events and generates unusual strains with unique genomic constellations derivative of parental rotavirus strains. Although most rotaviruses appear to be host restricted, the interspecies transmission of rotaviruses has been well documented across the globe. The nocturnal bats have been accepted harbouring many pathogenic viruses and serving as natural reservoirs. Indications are that bats can also harbour rotaviruses, and help in virus spread. The zooanthroponotic and anthropozoonotic potential of rotaviruses has significant implications for rotavirus epidemiology. Hitherto reports confirm infection of humans through rotaviruses of animal origin, exclusively via direct transmission or through gene reassortments between animal and human strain of rotaviruses. There is a need to understand the ecology and evolutionary biology of emerging rotavirus strains to design effective control programs.