Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, 17489 Greifswald-Insel Riems, Germany.
Department of Medicine, Karolinska Institutet, SE-17177 Stockholm, Sweden.
Viruses. 2021 Jun 27;13(7):1250. doi: 10.3390/v13071250.
Nairobi sheep disease orthonairovirus (NSDV) is a zoonotic tick-borne arbovirus, which causes severe gastroenteritis in small ruminants. To date, the virus is prevalent in East Africa and Asia. However, due to climate change, including the spread of transmitting tick vectors and increased animal movements, it is likely that the distribution range of NSDV is enlarging. In this project, sheep and cattle (hitherto classified as resistant to NSDV) were experimentally infected with NSDV for a comparative study of the species-specific pathogenesis. For this purpose, several new diagnostic assays (RT-qPCR, ELISA, iIFA, mVNT, PRNT) were developed, which will also be useful for future epidemiological investigations. All challenged sheep (three different doses groups) developed characteristic clinical signs, transient viremia and virus shedding-almost independent on the applied virus dose. Half of the sheep had to be euthanized due to severe clinical signs, including hemorrhagic diarrhea. In contrast, the course of infection in cattle was only subclinical. However, all ruminants showed seroconversion-implying that, indeed, both species are susceptible for NSDV. Hence, not only sheep but also cattle sera can be included in serological monitoring programs for the surveillance of NSDV occurrence and spread in the future.
内罗毕绵羊病正呼肠孤病毒（NSDV）是一种人畜共患的蜱传虫媒病毒，可导致小反刍动物严重的胃肠炎。迄今为止，该病毒在东非和亚洲流行。然而，由于气候变化，包括传播蜱虫媒介的扩散和动物活动的增加，NSDV 的分布范围可能正在扩大。在这个项目中，绵羊和牛（迄今被归类为对 NSDV 有抗性）被实验性感染 NSDV，以进行种特异性发病机制的比较研究。为此，开发了几种新的诊断检测方法（RT-qPCR、ELISA、iIFA、mVNT、PRNT），这些方法也将有助于未来的流行病学调查。所有受挑战的绵羊（三个不同剂量组）均出现特征性临床症状、短暂的病毒血症和病毒脱落——几乎与应用的病毒剂量无关。由于严重的临床症状，包括出血性腹泻，一半的绵羊不得不被安乐死。相比之下，牛的感染过程是亚临床的。然而，所有反刍动物均出现血清转化——这意味着，实际上，这两个物种对 NSDV 均易感。因此，不仅绵羊血清，而且牛血清都可以包含在未来针对 NSDV 发生和传播的血清学监测计划中。
