Phylogenetic analysis of classical swine fever virus (CSFV) field isolates from outbreaks in South and Central America.

I. GREISER-WILKE; A.J. PEREDA

Hannover -Germany

Congreso; Annual Meeting of the German Society of Virology; 2005

Classical swine fever virus (CSFV) belongs to the genus pestivirus within the family Flaviviridae, and causes severe losses to the pig industry almost worldwide. Up to date, there exists little information concerning the epidemiological situation of classical swine fever (CSF) in the Americas. Genotyping of isolates from outbreaks in domestic pigs in several countries of South and Central America was performed. In contrast to the situation in most parts of Europe, where group 2 isolates predominate, it was found that all the isolates from the American continent analyzed belonged to group 1 and were further resolved into three subgroups. The Cuban isolates clustered in subgroup 1.2, whereas the isolates from Honduras and Guatemala clustered in subgroup 1.3. The remaining isolates from Argentina, Brazil, Colombia and Mexico generated four poorly resolved clusters in subgroup 1.1, together with the vaccine strains, with historical European and US isolates. While the vaccine strains and the historical European isolates formed a relatively distinct cluster, the US isolates clustered together with Mexican and Columbian isolates, respectively. Our results indicate that the US isolates are closely related to isolates from South America, while the isolates from Cuba on one hand and from Central America on the other hand, seem to be unrelated. This allows the speculation that at least in the American continent, CSF virus may have appeared independently in several regions, and spreading to other countries and/or continents (Europe?) was a secondary effect.