title: Bovine ephemeral fever in Taiwan (2001-2002).
abstract: Bovine ephemeral fever (BEF), a vector-borne disease of cattle, is caused by the Ephemerovirus of the family Rhabdoviridae. In the past 40 years, Taiwan has had seven BEF epizootics, and we have previously reported the first five. This study summarizes the 2001 and 2002 epizootics; conducted case-control serologic studies on 10 herds involved in the 2001 epizootic; determined whether the recent BEF viruses have varied significantly; and discusses the relationship between epizootic patterns and possible variant BEF viruses. For mature cows that had received at least 2 doses of vaccine before the study, a negative correlation between the prevaccinated (the 3rd dose and after) serum neutralization antibody (SNA) titers and their postvaccinated peak rates was found. When prevaccinated SNA levels were at < or = 32, their postvaccinated SNA levels increased significantly faster (P<0.01) than for those at > or = 32. The glycoprotein gene of isolates from 1999, 2001, and 2002 had a 99.2-99.9% homology, without consistent amino acid variations in the neutralization sites. Phylogenetic analysis of Taiwanese isolates revealed 2 distinct clusters, the 1983-1989 and 1996-2002 isolates. Cross-neutralization tests confirmed the glycoprotein gene sequence analysis results. In conclusion, annual boosters at SNA levels > 32, at more than 2 doses, or at intervals shorter than 6 months are not advisable. The occurrence of frequent small epizootics implies the dominance of BEF virus over host immunity, but not a variant virus.
authors.affiliation: Department of Biology, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yao-Ching
authors.initials: YC
authors.lastname: Hsieh
authors.forename: Shih-Hui
authors.initials: SH
authors.lastname: Chen
authors.forename: Chin-Cheng
authors.initials: CC
authors.lastname: Chou
authors.forename: Lu-Jen
authors.initials: LJ
authors.lastname: Ting
authors.forename: Chitoshi
authors.initials: C
authors.lastname: Itakura
authors.forename: Fun-In
authors.initials: FI
authors.lastname: Wang
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D017931:DNA Primers; D004810:Ephemeral Fever / Q000453:epidemiology* / Q000235:genetics / Q000517:prevention & control*; D018115:Ephemeral Fever Virus, Bovine / Q000235:genetics*; D014644:Genetic Variation; D006023:Glycoproteins / Q000235:genetics; D008969:Molecular Sequence Data; D009500:Neutralization Tests / Q000662:veterinary; D010802:Phylogeny; D017422:Sequence Analysis, DNA / Q000662:veterinary; D017385:Sequence Homology; D013045:Species Specificity; D013624:Taiwan / Q000453:epidemiology; D014611:Vaccination / Q000662:veterinary*; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D017931:DNA Primers; D006023:Glycoproteins; D014759:Viral Envelope Proteins