Complete Genome Sequence of Bluetongue Virus Serotype 9: Implications for Serotyping

Abstract

bThe second complete genome of bluetongue virus serotype 9 (BTV-9) is presented in this report. The sequence analysis points to continued circulation in India of a mixed topotype virus apparently belonging to the BTV-9 serotype, and it raises questions about approaches for serotyping bluetongue viruses. Bluetongue virus (BTV) is a 10-segmented double-stranded RNA virus belonging to the genus Orbivirus, family Reoviridae. BTV infects most ruminant species, but the clinical disease is limited to sheep and, to some extent cattle (1-3, 11). Twenty-six serotypes of BTV are recognized (3,5), and the disease is endemic to many countries in Africa and Asia. Isolates from Asia appear to show more diversity, even though sequence information is available for only a few instances. In an effort to understand the diversity and molecular epidemiology for this virus, we recently reported the partial or complete genome analysis of isolates belonging to BTV serotypes 9, 10, and 21 (4, 10, 12). Here we report the complete sequence of the open reading frames of all 10 segments of a second BTV-9 virus. This virus, designated Ind-R1/07, was isolated from the southern state of Andhra Pradesh, India, in the year 2007. In contrast to whole-genome sequencing based on preamplified segments (7-10), we report here the use of next-generation sequencing (Illumina platform) to elucidate the nucleotide sequence information.The serotype of Ind-R1/07 was identified by sequencing. The size of the genome segments of BTV typically range from 822 to 3,944 bp. The 10 segments code for seven structural and five nonstructural proteins. The lengths of these proteins (in residues) in Ind-R1/07 virus are 1,302 (VP1), 955

Identification and genomic characterization of the first isolate of bluetongue virus serotype 5 detected in Australia

“…The considerable degree of cross neutralization between BTV‐9 and BTV‐5 found in this study (Tables and ), and previously documented by others (Rao et al . ), could explain the perceived existence of BTV‐5 antibodies in host animals in Eastern lineage regions. Our phylogenetic analysis of the relationships between Seg‐2 and Seg‐6 of BTV‐5 isolates showed that these belonged to Western topotype lineages (W‐1/W‐2) whereas for BTV‐9 isolates, both Western and Eastern lineage clades exist for this serotype, involving two Western lineages (W‐1/W‐2) and a single Eastern lineage (E‐1) (Figures a & b).…”

“…Of note was the finding in this study and by others previously (Rao et al ., ; Rao et al . ; Shirafuji et al . ; Maan et al .…”

Type-specific seroprevalence of bluetongue in Andhra Pradesh, India, during 2005–2009

“…Twenty-six different serotypes of BTV are recognized worldwide and distinct topotypes defined by closely related sequences of each genome segment have been proposed [19]. In India, 23 serotypes of BTV have been reported, identified either by serology or virus isolation, and eight serotypes (BTV-1, -2, -3, -9, -10, -16, -21, and -23) have been isolated from different regions during the last decade [4,5,8,12,17,22,26,28,30,33,36,37].BT is endemic in India. Multiple serotypes of BTV commonly circulate in the same geographical area, and can be isolated from the same flock or even from the same animals.…”

“…Recently three serotypes (BTV-3, -9, and -21) have been isolated from India [5,17,30,31,37] (http:// www.ainpbt.com/achievement.html). To select different serotypes of BTV for inclusion in polyvalent vaccines, a comprehensive and continuous type-specific sero-prevalence is needed.…”

Whole Genome Sequence Analysis of Bluetongue Virus Serotype 12 from Northern India

“…Till date, 15 BTV serotypes (BTV-1, BTV-2, BTV-3, BTV-4, BTV-5, BTV-6, BTV-9, BTV-10, BTV-12, BTV-16, BTV-17, BTV-18, BTV-21, BTV-23 and BTV-24) have been isolated in India since 2001 Rao et al, 2016;Biswas et al, 2010;Gollapalli et al, 2012;Dadawala et al, 2012;Rao et al, 2012;Himadri et al, 2016). BTV-12 has been isolated and sequenced earlier from Andhra Pradesh, one of the southern states of India in 2011 (Rao et al, 2015).…”