|Stadejek, T - NATL VET RES INST, POLAND|
|Warg, J - DVL-NVSL-VS-APHIS-USDA|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 9, 1996
Publication Date: N/A
Technical Abstract: Classical swine fever virus (CSFV), bovine viral diarrhea virus (BVDV), and border disease virus (BDV) of sheep make up the Pestivirus genus within the Flaviviridae family. The pestivirus genome is a single strain of positive- sense RNA approximately 12.5 Kb in length. The single, large open reading frame is preceded by a 361 to 386 base untranslated region (UTR). Comparison of the 5' UTR has led to the segregation of BVDV isolates into two distinct genotypes. In contrast, low variability of 5' UTR among European isolates of CSFV has been reported. In this study, one-step, single RT-PCR was used to determine the sequence of a 280 bp fragment from cDNA of the 5' UTR of 29 field isolates, vaccine and laboratory strains of CSFV from Poland, Germany, France, Belgium, Malaysia, USA, Mexico, Honduras, El Salvador, and Brazil. Nucleotide sequence comparison revealed high sequence homology with the most dissimilar isolates being more than 94% similar. Adaptation to different host cells or attenuation of virulence could not be correlated with specific sequence changes. Phylogenetic analysis segregated all isolates tested into one major group, indicating they belong in one genotype. Grouping by phylogenetic analysis correlated with geographic distribution with few exceptions. Distinct subgroups were apparent for European and American isolates. Three isolates from Malaysia were clustered within the European subgroup. Examination of a larger number of Asian isolates would be necessary to determine if these isolates are representative of all Asian isolates. These results suggest that 5' UTR sequence comparison could be employed in epidemiological studies.