HOMEPRODUCTSCOMPANYCONTACTFAQResearchDictionaryPharmaSign Up FREE or Login

Origin and evolution of viruses causing classical swine fever in Cuba.

Abstract
We have analyzed the origin and evolution of viruses from the classical swine fever (CSF) epidemic that affects Cuba since 2001 by nucleotide sequencing of regions within the E2 glycoprotein and the NS5B (polymerase) genes. The sequence of 190 nucleotides from E2 gene was determined for 10 CSF viruses isolated at different locations of the island, and used for phylogenetic analyses, including sequences from viruses of the 1993--1997 epizootic, previously determined, as well as those from representatives of the different CSFV genotypes. The phylogenetic tree obtained indicates that viruses circulating at present belong to the subgroup 1.2 and are closely related to those isolated during the 1993--1997 epizootic, including the strain Margarita used for vaccine potency tests in Cuba. However, the pattern of evolution revealed by these analyses was different than that observed previously, in which western isolates were almost identical to Margarita strain, while eastern isolates showed a higher level of genetic diversification. In this case, all the viruses analyzed grouped in an independent, define cluster that is closely related, albeit distinguishable, from that of Margarita-related viruses that previously circulated in the western part of Cuba. In addition, the 2001--2003 viruses showed a branched pattern with a level of sequence diversification similar to that observed in the eastern 1993--1997 viruses. Interestingly, a significant fraction (about 54%) of the mutations found in the E2 sequence led to amino acid replacements. This high rate of non-synonymous mutations was not found in the previous Cuban epizootic and has not been reported for other CSF outbreaks. In spite of these amino acid replacements, no antigenic changes were observed in the reactivity of different isolates with CSFV-specific MAbs and polyclonal sera. The phylogenetic tree derived from 409 nucleotides of NS5B gene of seven isolates and Margarita strain, was consistent with that obtained from E2 sequences. In this region, encoding a non-structural protein, a low level of fixation of non-synonymous mutations was observed. The results obtained suggests that epidemiological factors affecting CSFV spread during the current epizootic in Cuba can favour the fixation of non-synonymous mutation in the E2 gene, which could be associated with a lower severity in the clinical signs developed by most of the affected animals.
AuthorsHeidy Díaz de Arce, Llilianne Ganges, Maritza Barrera, Dany Naranjo, Francisco Sobrino, María Teresa Frías, José Ignacio Núñez
JournalVirus research (Virus Res) Vol. 112 Issue 1-2 Pg. 123-31 (Sep 2005) ISSN: 0168-1702 [Print] Netherlands
PMID15878213 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
Chemical References
  • Viral Envelope Proteins
  • glycoprotein E2, classical swine fever virus
Topics
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell Line
  • Classical Swine Fever (epidemiology, virology)
  • Classical Swine Fever Virus (classification, genetics)
  • Cuba (epidemiology)
  • Evolution, Molecular
  • Molecular Epidemiology
  • Molecular Sequence Data
  • Phylogeny
  • Sequence Alignment
  • Viral Envelope Proteins (chemistry, genetics)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research graph!


Choose Username:
Email:
Password:
Verify Password:
Enter Code Shown: