Faculty of Veterinary Medicine, Department of Anatomy and Physiology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania.
Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania.
Virol J. 2018 Nov 19;15(1):177. doi: 10.1186/s12985-018-1090-8.
The emergence in 2014 and persistence of African Swine Fever (ASF) in Lithuania has been linked to infected wild boar movement and close contact with the carcasses of other infected wild boars. Over time the number of reported cases of ASF in wild boars gradually increased, but no detailed epidemiological data has been available. Therefore, the objective of the present study was to determine ASF virus prevalence in wild boars and domestic pigs during the 2014-2017 period and further explore the current geographical distribution of the virus.
Our study results show that ASF virus prevalence in hunted wild boars using PCR analysis increased from 0.83% (95% CI 0.69-0.98) to 2.27% (95% CI 2.05-2.48) from 2014 to 2016 respectively. However, there was a dramatic jump in the number of ASF positive wild boars cases in 2017 resulting in prevalence of 12.39% (95% CI 11.91-12.86) (p < 0.05). The average prevalence of ASF-specific antibodies in wild boar population during years 2014-2017 was 0.45% (95% CI 0.39-0.51) based on ELISA test results. Prevalence of ASF virus in domestic pigs ranged from 0.24% (95% CI 0.17% - 0.32) in 2015 to 2.74% (95% CI 2.33% - 3.15) in 2017. The average seasonal prevalence of ASF virus in pigs was statistically significant (p < 0.05) and ranged from 0% in spring to 3.68% (95% CI 3.32-4.05) in summer. Correlation between the pig density and number of recorded pig ASF cases in affected regions was only found in 2017 (R = 0.78, p < 0.05). No correlation was detected between the wild boar density and number of recorded pig or wild boar ASF - positive cases.
This study provides the first results of ASF virus prevalence changes in Lithuania during the 2014-2017. The overall results confirm the relatively high prevalence of ASF virus in wild boar that was gradually increasing from 2014 to 2017. In the last year of study, the number of ASF positive cases in both domestic pigs and wild boars had unexpectedly increased several times. A better understanding of current status of the disease will enable better control and prevent further spread of ASF virus in Western Europe.
2014 年非洲猪瘟（ASF）的出现和持续存在与感染野猪的移动以及与其他感染野猪尸体的密切接触有关。随着时间的推移，野猪中报告的 ASF 病例数量逐渐增加，但没有详细的流行病学数据。因此，本研究的目的是确定 2014-2017 年期间野猪和家猪中 ASF 病毒的流行情况，并进一步探讨病毒的当前地理分布。
我们的研究结果表明，使用 PCR 分析检测到，2014 年至 2016 年期间，被猎杀野猪中 ASF 病毒的流行率从 0.83%（95%CI 0.69-0.98）分别增加到 2.27%（95%CI 2.05-2.48）。然而，2017 年 ASF 阳性野猪病例数量急剧增加，导致流行率为 12.39%（95%CI 11.91-12.86）（p<0.05）。根据 ELISA 检测结果，2014-2017 年期间，野猪群体中 ASF 特异性抗体的平均流行率为 0.45%（95%CI 0.39-0.51）。家猪中 ASF 病毒的流行率范围为 2015 年的 0.24%（95%CI 0.17%-0.32%）至 2017 年的 2.74%（95%CI 2.33%-3.15%）。ASF 病毒在家猪中的季节性流行率具有统计学意义（p<0.05），范围从春季的 0%到夏季的 3.68%（95%CI 3.32-4.05）。仅在 2017 年，受影响地区的猪密度与记录的猪 ASF 病例数之间存在相关性（R=0.78，p<0.05）。未检测到野猪密度与记录的猪或野猪 ASF 阳性病例数之间的相关性。
本研究提供了 2014-2017 年期间立陶宛 ASF 病毒流行率变化的首次结果。总体结果证实，野猪中 ASF 病毒的流行率相对较高，从 2014 年到 2017 年逐渐增加。在研究的最后一年，家猪和野猪中 ASF 阳性病例的数量出人意料地增加了数倍。更好地了解疾病的现状将使 ASF 病毒在西欧的控制和预防进一步传播成为可能。
