Animal Health Institute, Sebeta, Ethiopia.
Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
BMC Vet Res. 2024 Oct 17;20(1):473. doi: 10.1186/s12917-024-04313-3.
Peste des Petits Ruminants (PPR) is a highly contagious viral disease primarily affecting goats and sheep, with clinical manifestations ranging from peracute disease to subclinical infection, particularly in atypical hosts such as cattle. The role of atypical hosts such as cattle to the spread of PPR remains controversial, with conflicting reports in the literature. Despite its worldwide significance, considerable knowledge gaps exist regarding the pathogenesis and clinical progression in both primary and atypical hosts. This study aimed to elucidate the tissue tropism, pathogenesis, virus shedding, clinical progression, and pathology associated with experimental PPR virus infection in indigenous goats and cattle. To this end, 32 animals-16 goats and 16 cattle-were intranasally inoculated with the Ethiopia/Habru/2014 Lineage-IV strain of the PPR virus followed by detailed clinical evaluations and systematic sampling at pre-established intervals to assess serological conversion, viral shedding, and the pathogenesis of the infection across both species.
The results show that goats exhibited typical clinical signs 4 days post-inoculation, with seroconversion by day 6 and early detection of viral RNA in swabs and tissues by day 3 and virus isolation starting day 4. In contrast, cattle exhibited minimal clinical signs, with seroconversion occurring at day 8 with viral RNA detected in tissue samples at day 4 and virus isolation starting day 6 in tissues and in a single nasal swab at day 8. Clinical scores and tissue positivity rates significantly differed between goats and cattle (P = 0.007 and P < 0.001, respectively). While goats exhibited expected gross and histopathological lesions, cattle showed only nonspecific lesions.
Together, our findings highlight the importance of comparative pathology studies for better understanding virus dynamics and transmission pathways that may help inform more effective PPR control programs. Future research should explore the pathogenesis of different PPRV lineages in cattle, assessing variations in disease progression and potential for epidemiological impact.
小反刍兽疫（PPR）是一种高度传染性的病毒性疾病，主要影响山羊和绵羊，其临床表现从急性疾病到亚临床感染不等，特别是在牛等非典型宿主中。牛等非典型宿主在 PPR 传播中的作用仍存在争议，文献中存在相互矛盾的报道。尽管 PPR 在全球范围内具有重要意义，但在原发性和非典型宿主中的发病机制和临床进展方面仍存在相当大的知识空白。本研究旨在阐明实验性 PPR 病毒感染在本地山羊和牛中的组织嗜性、发病机制、病毒脱落、临床进展和病理学。为此，32 只动物-16 只山羊和 16 只牛-通过鼻腔接种埃塞俄比亚/哈布鲁/2014 株四系 PPR 病毒，随后进行详细的临床评估和系统采样，以评估血清学转换、病毒脱落和两种物种的感染发病机制。
结果表明，山羊在接种后第 4 天出现典型临床症状，第 6 天血清转化，第 3 天开始在拭子和组织中早期检测到病毒 RNA，第 4 天开始分离病毒。相比之下，牛表现出最小的临床症状，第 8 天血清转化，第 4 天组织样本中检测到病毒 RNA，第 6 天开始在组织和第 8 天的单个鼻腔拭子中分离病毒。山羊和牛的临床评分和组织阳性率有显著差异（P=0.007 和 P<0.001）。虽然山羊表现出预期的大体和组织病理学病变，但牛只表现出非特异性病变。
综上所述，我们的研究结果强调了比较病理学研究的重要性，以便更好地了解病毒动力学和传播途径，这可能有助于制定更有效的 PPR 控制计划。未来的研究应探索不同 PPRV 谱系在牛中的发病机制，评估疾病进展的变化和潜在的流行病学影响。
