Immunology Laboratory, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, 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. 2020 Oct 7;17(1):148. doi: 10.1186/s12985-020-01422-x.
The first cases of African swine fever (ASF) were detected in the Lithuanian wild boar population in 2014. Since then, the disease spread slowly through the whole country, affecting both, wild boar and domestic pigs. In the other Baltic states, which both are also affected by ASF since 2014, the recent course of ASF prevalence suggests that the countries might be well under way of disease elimination. In contrast, in Lithuania the epidemic seems to be still in full progress. In the present study, we aimed to extend a previous prevalence study in Lithuania. Looking at ASF virus (ASFV) and seroprevalence estimates of wild boar in all months of 2018 and in all affected municipalities in Lithuania, the course of ASF was evaluated on a temporal and spatial scale. A non-spatial beta-binomial model was used to correct for under- or overestimation of the average prevalence estimates. Within 2018 no big differences between the prevalence estimates were seen over time. Despite of the lower sample size, highest ASFV prevalence estimates were found in dead wild boar, suggesting higher detection rates through passive surveillance than through active surveillance. Accordingly, with the maximum prevalence of 87.5% in May 2018, the ASFV prevalence estimates were very high in wild boar found dead. The number of samples originating from hunted animals (active surveillance) predominated clearly. However, the ASFV prevalence in those animals was lower with a maximum value of 2.1%, emphasizing the high value of passive surveillance. A slight increase of the seroprevalence in hunted wild boar could be seen over time. In the center of Lithuania, a cluster of municipalities with high ASFV and seroprevalence estimates was found. The results of the study indicate that ASFV is still circulating within the Lithuanian wild boar population, constituting a permanent risk of disease transmission into domestic pig holdings. However, additional, more recent data analyses are necessary to re-evaluate the course of ASF in Lithuania and thus, to be able to make a statement about the stage of the ASF epidemic in the country. This is of huge importance for Lithuania for evaluating control measures and their efficacy, but also for neighbouring countries to assess the risk of disease spread from Lithuania.
2014 年，立陶宛野猪群中首次检测到非洲猪瘟（ASF）病例。此后，该疾病在全国范围内缓慢传播，影响了野猪和家猪。在另外两个波罗的海国家（自 2014 年以来也受到 ASF 的影响），ASF 最近的流行趋势表明，这些国家可能已经很好地消除了疾病。相比之下，在立陶宛，疫情似乎仍在全面蔓延。在本研究中，我们旨在扩展立陶宛之前的流行情况研究。通过观察 2018 年所有月份立陶宛所有受影响地区野猪的 ASF 病毒（ASFV）和血清阳性率估计值，从时间和空间尺度评估 ASF 的流行情况。使用非空间贝塔二项式模型来纠正平均流行率估计值的过高或过低估计。2018 年内，随着时间的推移，流行率估计值之间没有太大差异。尽管样本量较小，但在发现死亡的野猪中发现了最高的 ASFV 流行率估计值，这表明通过被动监测比主动监测发现的检测率更高。因此，2018 年 5 月 ASFV 流行率估计值高达 87.5%，在发现死亡的野猪中非常高。来自狩猎动物的样本数量（主动监测）明显占主导地位。然而，这些动物中的 ASFV 流行率较低，最大值为 2.1%，强调了被动监测的高价值。随着时间的推移，在狩猎野猪中发现的血清阳性率略有增加。在立陶宛中部，发现了一个具有高 ASFV 和血清阳性率估计值的市政区集群。研究结果表明，ASFV 仍在立陶宛野猪群中传播，对家猪养殖场的疾病传播构成持续威胁。然而，需要进行额外的、更近期的数据分析，以重新评估立陶宛 ASF 的流行情况，从而能够对该国 ASF 流行的阶段做出声明。这对评估立陶宛的控制措施及其效力以及评估来自立陶宛的疾病传播风险具有重要意义。
