GLOBAL ISOLATES OF BLUETONGUE VIRUS SEGREGATE INTO REGION-SPECIFIC TOPOTYPES BASED ON PHYLOGENEIC ANALYSIS OF THEIR NS3 GENE

Authors: BALASURIYA, UDENI - UNIV OF CA-DAVIS; NADLER, STEVEN - UNIV OF CA-DAVIS; Wilson, William - Bill; PRITCHARD, L. IAN - AUSTRALIAN ANIM HEALTH; SMYTHE, ASHLEIGH - UNIV OF CA-DAVIS; DE SANTIS, PAOLA - IZS AM ITALY; NIANZU, ZHANG - YUNNAN TROPICAL/SUBTROPIC; Tabachnick, Walter; MACLACHLAN, N. JAMES - UNIF OF CA-DAVIS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2003
Publication Date: 10/1/2003
Citation: Balasuriya, U.B., Nadler, S.A., Wilson, W.C., Pritchard, L., Smythe, A.B., De Santis, P., Nianzu, Z., Tabachnick, W.J., Maclachlan, N. 2003. Global isolates of bluetongue virus segregate into region-specific topotypes based on phylogeneic analysis of their NS3 gene [abstract]. OIE Symposium on Bluetongue Virus, Taormina, Italy. Paper No C1, p. 88.

Interpretive Summary: Bluetongue (BT) is a non-contagious viral disease of ruminant animals that is transmitted by hematophagous Culicoides midges. BT is 1 of 15 animal diseases included in List A of the Office International des Epizooties (OIE), and current international trade regulations are based on the premise that BT is an emerging disease spread by animal movement. Genetic analysis of 100 strains of BT from around the world indicated region-specific grouping of global isolates of BTV is consistent with prolonged co-evolution of BTV with the different species of vector insects that occur in each region.

Technical Abstract: Bluetongue (BT) is a non-contagious viral disease of ruminant animals that is transmitted by hematophagous Culicoides midges. BT is 1 of 15 animal diseases included in List A of the Office International des Epizooties (OIE), and current international trade regulations are based on the premise that BT is an emerging disease spread by animal movement. We used phylogenetic analyses of the gene encoding the conserved NS3 protein of 100 strains of BT virus (BTV) from different regions of the world to show that these viruses reliably segregate into groupings reflective of their geographic origin and respective species of Culicoides vector, regardless of virus serotype or year of isolation. The fact that the viruses segregated into distinct African/European, Asian/Australian, Central American/Caribbean Islands, and North American groupings indicates that BTV has not recently been disseminated around the world by animal movement. Rather, the region-specific grouping of global isolates of BTV is consistent with prolonged co-evolution of BTV with the different species of vector insects that occur in each region.