Identification and Molecular Characterisation of Bovine Parainfluenza Virus-3 and Bovine Respiratory Syncytial Virus - First Report from Turkey

Timurkan, Mehmet Ozkan; Aydin, Hakan; Sait, Ahmet

Enveloped viruses, paramyxoviruses in particular, are generally susceptible when exposed to the outside environment. Pirtle and Beran (27) reported that when diluted to 10 5.5 CCID50/mL and used to contaminate different kinds of media, the viability time was 1.5 h on rubber gloves, 20 min on skin, and a maximum of 6 h on an indoor surface. This is why samples must be admitted to the laboratory in a short time and tested in the shortest time possible. When low positivity rates are considered, both in this study and worldwide, there is always the possibility of false negativity because of virus sensitivity. PCRs specific for the gene-encoding fusion region for BRSV and the matrix gene for BPIV3 were used. The fusion gene of BRSV is a region that determines antigenic variations (26) , and the matrix gene for BPIV3 is responsible for viral assembly, pathogenesis, and antigenicity of strains (20, 21) . Phylogenetic analysis of BRSV based on the F protein sequence classified the isolates into seven different subgroups. The topology of the phylogeny was retained when an analysis of the N and G protein gene sequences was conducted (36) . In our study, the determined strain was found to belong to subgroup III. Knowing the genotypes helps to determine the typespecific vaccine selection in the geographic region. Valarcher et al. (36) identified vaccine failure among animals infected with BRSV groups V and VI, indicating that commercial vaccines act poorly against infections caused by such viral groups. Therefore, selection of vaccines is important and should be specific to the type of strains present in the region. For example in the 2000s in Europe, vaccines including Rispoval RS (strain RB-94, subgroup II), Bayovac (strain Lehmkuhl 375, subgroup III), and Vacores (strain 220/69, subgroup II) were used. If these vaccines were currently in use, Bayovac could be suitable for our country. However, in vivo trials would be required for other vaccines. Therefore, genotyping studies of viruses are necessary for molecular epidemiology and vaccine studies.