Stankevicius Arunas, Buitkuviene Jurate, Sutkiene Virginija, Spancerniene Ugne, Pampariene Ina, Pautienius Arnoldas, Oberauskas Vaidas, Zilinskas Henrikas, Zymantiene Judita
Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes st. 18, LT-47182, Kaunas, Lithuania.
National Food and Veterinary Risk Assessment Institute, J. Kairiukscio st. 10, LT-08409, Vilnius, Lithuania.
Acta Vet Scand. 2016 Sep 8;58(1):51. doi: 10.1186/s13028-016-0232-5.
Porcine reproductive and respiratory syndrome virus (PRRSV) is recognized worldwide as an important and economically devastating pathogen in pig production. Although PRRSV is widespread in domestic swine, there is a lack of information regarding PRRSV infection in European wild boars (Sus scrofa). Currently available information does not provide conclusive evidence that wild boars are a reservoir of PRRSV. Nevertheless, wild boars may be likely to become infected by domestic swine through occasional direct or indirect contact. Furthermore, wild boars can act as a reservoir for infectious diseases of domestic pigs. Therefore, the objectives of the present study were to determine the virus prevalence and further explore the epidemiology and diversity of PRRSV strains present in Lithuanian wild boars over a 5-year period. A total of 1597 tissue and serum samples from wild boars inhabiting 44 districts and ten counties in Lithuania were analysed using conventional nested reverse transcription polymerase chain reaction (RT-PCR) and real-time Taqman RT-PCR for the detection of PRRSV-specific open reading frame (ORF) 1 and 6 sequences.
PRRSV was highly prevalent in Lithuanian wild boar populations, with an average rate of 18.66 % using conventional RT-PCR and 19.54 % using real-time RT-PCR. PRRSV was detected in 36.71 and 41.77 % of 237 hunting grounds tested by conventional RT-nPCR and real-time RT-PCR, respectively. No statistically significant differences in PRRSV prevalence were observed by geographic area in the ten Lithuanian counties. Animals infected with PRRSV were identified in all age groups; however, significantly higher prevalence rates were identified in subadult and adult wild boars than in juveniles up to 12 months old. No positive results were obtained using conventional PCR with Type 2 specific primers. Phylogenetic analysis of the partial ORF5 region revealed that ten wild boars harboured virus sequences belonging to genetic subtypes 3 and 4 and may therefore pose a serious threat to Lithuanian pig farms in which only subtype two strains are circulating.
The results of virus prevalence and phylogenetic analyses strongly support the role of wild boars as a possible natural reservoir for PRRSV in Lithuania.
猪繁殖与呼吸综合征病毒（PRRSV）在全球范围内被公认为是猪生产中一种重要且具有经济破坏性的病原体。尽管PRRSV在家猪中广泛传播，但关于欧洲野猪（Sus scrofa）感染PRRSV的信息却很匮乏。目前可得的信息并未提供确凿证据表明野猪是PRRSV的储存宿主。然而，野猪可能会通过偶尔的直接或间接接触而被家猪感染。此外，野猪可作为家猪传染病的储存宿主。因此，本研究的目的是确定病毒流行率，并进一步探究立陶宛野猪在5年期间PRRSV毒株的流行病学及多样性情况。使用常规巢式逆转录聚合酶链反应（RT-PCR）和实时Taqman RT-PCR对来自立陶宛44个区和10个县的1597份野猪组织和血清样本进行分析，以检测PRRSV特异性开放阅读框（ORF）1和6序列。
PRRSV在立陶宛野猪种群中高度流行，常规RT-PCR检测的平均阳性率为18.66%，实时RT-PCR检测的平均阳性率为19.54%。在分别用常规RT-nPCR和实时RT-PCR检测的237个狩猎场中，PRRSV的检出率分别为36.71%和41.77%。在立陶宛的10个县中，未观察到PRRSV流行率在地理区域上存在统计学显著差异。所有年龄组的动物中均鉴定出感染PRRSV的个体；然而，亚成年和成年野猪的流行率显著高于12月龄以下的幼年野猪。使用2型特异性引物进行常规PCR未获得阳性结果。对部分ORF5区域的系统发育分析表明，10头野猪携带属于基因亚型3和4的病毒序列，因此可能对立陶宛仅流行2型毒株的猪场构成严重威胁。
病毒流行率和系统发育分析结果有力地支持了野猪作为立陶宛PRRSV可能的自然储存宿主的作用。
