Molecular Characterization of Avian Rotaviruses F and G Detected in Brazilian Poultry Flocks

Abstract

Avian rotaviruses (RVs) are important etiologic agents of gastroenteritis in birds. In general, avian RVs are understudied; consequently, there is a paucity of information regarding these viruses. Therefore, the characterization of these viral species is highly relevant because more robust information on genetic, epidemiologic, and evolutionary characteristics can clarify the importance of these infections, and inform efficient prevention and control measures. In this study, we describe partial genome characterizations of two avian RV species, RVF and RVG, detected in asymptomatic poultry flocks in Brazil. Complete or partial sequences of at least one of the genomic segments encoding VP1, VP2, VP4, VP6, VP7, NSP1, NSP4, NSP4, or NSP5 of 23 RVF and 3 RVG strains were obtained, and demonstrated that multiple variants of both RVF and RVG circulate among Brazilian poultry. In this study, new and important information regarding the genomic characteristics of RVF and RVG is described. In addition, the circulation of these viruses in the study region and the genetic variability of the strains detected are demonstrated. Thus, the data generated in this work should help in understanding the genetics and ecology of these viruses. Nonetheless, the availability of a greater number of sequences is necessary to advance the understanding of the evolution and zoonotic potential of these viruses.

Keywords: RVF; RVG; chickens; genome sequencing; rotavirus.

Figure 1

Map of Brazil showing the study region (circle; ES = Espírito Santo and RJ = Rio de Janeiro), located in the southeast of the country (A). Maps of the locations where fecal samples were obtained from birds analyzed in this study: (B) map of the state of Rio de Janeiro showing the cities of São José do Vale do Rio Preto in the East Region, and Bom Jardim in Bom Jardim in the Center Region of the state; (C) map of the state of Espírito Santo showing the city of Marechal Floriano in the Southwest Region of the state.

Figure 2

Dendrograms constructed from complete or partial sequences of the VP1, VP2, VP4, VP6, VP7, NSP1, NSP2, NSP4, and NSP5-encoding genome segments of RVF strains. Distances were corrected using the Kimura 2-parameter model. The dendrogram was constructed using the maximum likelihood method. Statistical support was provided by bootstrapping 1000 pseudoreplicates. Bootstrap values above 70% are given as branch nodes. GenBank reference strain accession numbers are shown next to the strain identification. RVF strains detected in this study are indicated by black triangles.

Figure 2

Dendrograms constructed from complete or partial sequences of the VP1, VP2, VP4, VP6, VP7, NSP1, NSP2, NSP4, and NSP5-encoding genome segments of RVF strains. Distances were corrected using the Kimura 2-parameter model. The dendrogram was constructed using the maximum likelihood method. Statistical support was provided by bootstrapping 1000 pseudoreplicates. Bootstrap values above 70% are given as branch nodes. GenBank reference strain accession numbers are shown next to the strain identification. RVF strains detected in this study are indicated by black triangles.

Figure 3

Dendrograms constructed from complete or partial sequences of the VP6, NSP2, and NSP5-encoding genome segments of RVG strains. Distances were corrected using the Kimura 2-parameter model, and the dendrogram was constructed using the maximum likelihood method. Statistical support was provided by bootstrapping 1000 pseudoreplicates. Bootstrap values above 70% are given as branch nodes. GenBank reference strain accession numbers are shown next to the strain identification. RVG strains detected in this study are indicated by black triangles.