Palestine-Korea Biotechnology Research Center, Palestine Polytechnic University, P.O. Box 198, Hebron, Palestine.
Palestine-Korea Biotechnology Research Center, Palestine Polytechnic University, P.O. Box 198, Hebron, Palestine.
Infect Genet Evol. 2023 Aug;112:105448. doi: 10.1016/j.meegid.2023.105448. Epub 2023 May 20.
Contagious ecthyma in small ruminants is a zoonotic disease caused by Orf virus (ORFV) in the genus Parapoxvirus that can be deadly to its natural hosts. It causes significant losses worldwide, and commonly infects humans. However, the literature about its comparative severity in sheep and goat hosts is misleading; and while contagious ecthyma has been shown to occur in camels and transmit to humans, there is confusion as to whether ORFV is responsible. Camels are important from a 'One Health' perspective as they have been implicated as a reservoir host for the virus causing Middle East Respiratory Syndrome (MERS), which has a case fatality rate of 35% in humans. We compared ORFV gene sequences and mortality data from the West Bank in Palestine, where ORFV has not been reported previously, with data from the region. Surprisingly, we found that infections of camels that had been attributed to ORFV were more closely related to a different member of the genus Parapoxvirus. Two Middle East ORFVs isolated from humans were unrelated and sat alongside sheep and goat derived sequences on two distinct ORFV lineages of a maximum likelihood B2L gene tree. One of the viral lineages bifurcated to produce a monophyletic group of goat-derived ORFVs characterized uniquely by a glycine at amino acid reside 249. We found that serine is the ancestral allele shared between ORFV infections of sheep and also two closely related Parapoxviruses (PCPV and CCEV), indicating that the glycine allele represents a more recent shift in virus host range adaptation to goats. Furthermore, and contrary to some reports that ORFV is more severe in goats than in sheep, we observed median mortality of up to 24.5% in sheep, but none in goats. We also identified trans-boundary spread of ORFV between the West Bank and Israel.
小反刍动物接触传染性脓疱病是由副痘病毒属的口疮病毒（ORFV）引起的一种人畜共患疾病，对其自然宿主具有致命性。它在全球范围内造成了重大损失，通常也会感染人类。然而，有关绵羊和山羊宿主中该疾病严重程度的文献存在误导；虽然接触传染性脓疱病已被证明会在骆驼中发生并传染给人类，但对于 ORFV 是否是罪魁祸首存在混淆。从“同一健康”的角度来看，骆驼很重要，因为它们被认为是中东呼吸综合征（MERS）病毒的宿主，这种病毒在人类中的病死率为 35%。我们比较了西岸（巴勒斯坦）以前没有报告过 ORFV 的基因序列和死亡率数据与该地区的数据。令人惊讶的是，我们发现，归因于 ORFV 的骆驼感染与副痘病毒属的另一种病毒更为密切相关。从人类中分离出的两种中东 ORFV 与绵羊和山羊衍生的序列不相关，而是位于最大似然 B2L 基因树的两个不同 ORFV 谱系上。两个谱系之一分支产生了一组独特的由 249 位氨基酸处的甘氨酸特征的山羊衍生的 ORFV 单系群。我们发现，丝氨酸是绵羊和两种密切相关的副痘病毒（PCPV 和 CCEV）之间 ORFV 感染的祖先等位基因，表明甘氨酸等位基因代表了病毒宿主范围适应山羊的近期转变。此外，与一些报道称 ORFV 在山羊中比在绵羊中更严重的情况相反，我们观察到绵羊的死亡率中位数高达 24.5%，而山羊则没有。我们还发现了 ORFV 在西岸和以色列之间的跨界传播。
