Evidence of bluetongue virus serotype 21 (BTV-21) divergence

Abstract

Bluetongue virus serotype 21 (BTV-21) was originally isolated from Australia, but has now been reported from India, Indonesia, China and Japan. We report the isolation, and sequencing of BTV-21 from India. The complete ORF sequence of VP2 gene of this isolate showed that it is closely related to recent BTV-21 isolates from Japan (93-94% identity), and distantly related to BTV-21 reference strain (86% identity). Our results, along with the available sequences of Japanese isolates, suggest that the currently circulating BTV-21 strains from India and Japan are divergent from the original strain(s) from Australia and shed light on designing molecular diagnostics for the detection of BTV.

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.…”

“…BTV-1 and -23 [16], BTV-2 [35], BTV-9 [31], BTV-10 [12], and BTV-21 [37] were used. The TCID 50 of the viruses was determined in Vero cells.…”

Complete Genome Sequence of Bluetongue Virus Serotype 16 of Goat Origin from India

“…Out of these 24 serotypes, 21 have been reported from India (8). Recently, the 22nd isolate, BTV21 has also been isolated in India (11).…”

New Approaches for Diagnosis of Viral Diseases in Animals

“…used in molecular diagnosis of viruses. The PCR amplified products can be used for nucleic acid sequencing to confirmatory diagnosis and detection of phylogenetic variations ( Figure 7) and new strains of pathogens (Susmitha et al, 2012).…”