Molecular and genetic characteristics of small ruminant lentiviruses in Slovenia

Abstract

Small ruminant lentiviruses (SRLV) are spread throughout the world, including Slovenia, where the first evidence of caprine arthritis encephalitis virus (CAEV) infection was found in 1996. This study was conducted to investigate the molecular and genetic characteristics of SRLV infection in Slovenia in order to classify our strains in relation to other known SRLV strains worldwide as well as to establish molecular techniques in concordance with serology. In this study, 340 goats and sheep were tested. Serological examination revealed that 57% of the goats and only 14% of the sheep were seropositive. The results of this study also show that the polymerase chain reaction (PCR) used in this study is less reliable than ELISA, with only 60.6% of the seropositive animals being PCR positive. Thirty-eight nucleotide sequences of the gag region encoding the matrix protein were determined and compared to sequences derived from the GenBank, revealing that Slovenian SRLV strains belong to sequence groups A and B, being maedivisna virus (MVV) and CAEV-like, respectively. In one goat herd, the presence of more than one genotype was confirmed and the majority of goat SRLV sequences were more closely related to MVV than to CAEV prototype strains.

Diagnostic performance of ID Screen® MVV-CAEV Indirect Screening ELISA in identifying small ruminant lentiviruses-infected goats

“…Given that accuracy of ELISAs can be affected by genotype of the infecting virus (Carroza et al 2009, de Andrés et al 2013, it is possible that diagnostic performance may differ between goat populations. However, Polish goats seem to be infected mainly with genotypes A and B (Olech et al unpublished data), which also predominate in other European countries (Kuhar et al 2013, Rachid et al 2013). This fact allows for cautious generalization of obtained results to other European goat populations.…”

Development and validation of TaqMan probe based real time PCR assays for the specific detection of genotype A and B small ruminant lentivirus strains

“…Since the phylogenetic analysis of Slovenian SRLV strains revealed that ovine strains belong to genotype A and caprine strains to genotypes A and B [15,19], two assays were designed for the specific detection of genotype A (MVV assay) and genotype B (CAEV assay) SRLV strains, based mainly on nucleotide sequences from Slovenian strains, as well as nucleotide sequences retrieved from GenBank. Since it is known that SRLV can cross the inter-species barrier [3], it was also designed to differentiate between MVV and CAEV.…”

“…Blood samples from all animals were taken by jugular venipuncture for both serum and whole blood collection, using 10 ml vacutainers without anticoagulant and 10 ml EDTA vacutainers, respectively. Samples were stored at −20°C until further use, unless peripheral blood leucocytes (PBL) were isolated from whole blood as previously described [19]. Sera samples from the animals investigated were tested for the presence of specific antibodies using a commercial ELISA assay Chekit-CAEV/MVV Screening ELISA Test Kit (IDEXX Laboratories) according to the manufacturer’s instructions.…”

“…Sera samples from the animals investigated were tested for the presence of specific antibodies using a commercial ELISA assay Chekit-CAEV/MVV Screening ELISA Test Kit (IDEXX Laboratories) according to the manufacturer’s instructions. Genomic DNA was extracted from peripheral blood leucocytes as previously described [19]. …”

“…Genotype E has only been detected in Italy and it contains two subtypes, E1 and E2 [10,11]. Phylogenetic analysis of SRLVs also supports evidence of natural cross-species transmission [3,15,19], which needs to be considered in disease control.…”