European Union Reference Laboratory for African Swine Fever (EURL), Centro de Investigación en Sanidad Animal, INIA-CISA, Valdeolmos, 28130, Madrid, Spain.
Estonian NRL: Estonian Veterinary and Food Laboratory, Kreutzwaldi 30, Tartu, 51006, Estonia.
Vet Microbiol. 2018 Jun;219:70-79. doi: 10.1016/j.vetmic.2018.04.001. Epub 2018 Apr 7.
Since its arrival in the Caucasus and Russia in 2007, African swine fever virus (ASFV) has spread widely and has now affected the EU countries of Estonia, Latvia, Lithuania, Poland and, more recently, the Czech Republic and Romania. The ever-increasing evidence of seropositive wild boar in certain areas suggests that some animals may be surviving for some time or could even be recovering from the disease. This could be due to acquired immunity after the primary infection and/or the presence of related viruses of reduced virulence. To assess these hypotheses, two ASFV field strains from Estonia were studied in vivo in two groups of domestic pigs. After an incubation period of 4 ± 1.6 days, the pigs inoculated intramuscularly with Es15/WB-Tartu 14 ASFV (group 2) developed clinical signs associated with acute disease and succumbed 7 and 11 days post infection (dpi). Pigs inoculated with Es15/WB-Valga-14 ASFV (group 1) had longer incubation times (8 days) than those in group 2 and developed variable clinical signs and lesions compatible with subacute and chronic forms of ASF; they succumbed at 11 and 25 dpi. The in-contact pigs in both groups became infected 7-14 days after exposure and exhibited variable clinical manifestations and pathological findings ranging from acute to chronic disease. Two animals per group recovered completely after infection and were protected against a subsequent homologous virus challenge-exposure performed at 78 dpi. Under experimental conditions, no transmission occurred from the survivors to susceptible sentinel pigs housed together with the survivors 137 days after the primary infection.
自 2007 年在高加索地区和俄罗斯出现以来，非洲猪瘟病毒（ASFV）已广泛传播，现已影响到欧盟国家爱沙尼亚、拉脱维亚、立陶宛、波兰，最近还影响到捷克共和国和罗马尼亚。某些地区野猪血清阳性的证据不断增加，这表明某些动物可能在一段时间内幸存下来，甚至可能从疾病中恢复。这可能是由于初次感染后获得了免疫力，和/或存在毒力降低的相关病毒。为了评估这些假设，对来自爱沙尼亚的两种 ASFV 田间毒株在两组家猪体内进行了研究。在 4±1.6 天的潜伏期后，经肌肉内接种 Es15/WB-Tartu 14 ASFV 的猪（第 2 组）出现了与急性疾病相关的临床症状，并在感染后 7 和 11 天死亡。接种 Es15/WB-Valga-14 ASFV 的猪（第 1 组）的潜伏期比第 2 组长（8 天），并出现了与 ASF 亚急性和慢性形式相吻合的可变临床症状和病变；它们在 11 和 25 dpi 死亡。两组接触猪在暴露后 7-14 天内感染，并表现出从急性到慢性疾病的可变临床表现和病理发现。每组中的两只动物在感染后完全康复，并在 78 dpi 进行同源病毒挑战-暴露后得到保护。在实验条件下，从幸存者到与幸存者一起饲养的易感哨兵猪之间没有发生传播，初次感染后 137 天。
