Rift valley fever (RVF) is a vector-borne viral disease of domestic ruminants, camels and man, characterized by widespread abortions and neonatal deaths in animals, and flu-like symptoms, which can progress to hepatitis and encephalitis in humans. The disease is endemic in Africa, Saudi Arabia and Yemen, and outbreaks occur after periods of high rainfall, or in environments supporting the proliferation of RVF virus (RVFV)-infected mosquito vectors. The domestic and wild animal maintenance hosts of RVFV, which may serve as sources of virus during inter-epidemic periods (IEPs) and contribute to occurrence of sporadic outbreaks, remain unknown, although reports indicate that the African buffalo (Syncerus caffer) may play a role. Due to the close proximity of the habitats of domestic pigs and warthogs to those of known domestic and wild ruminant RVFV maintenance hosts respectively, our study investigated their possible role in the epidemiology of RVF in South Africa by evaluating RVFV exposure and seroconversion in suids. A total of 107 warthog and 3,984 domestic pig sera from 2 and all 9 provinces of South Africa, respectively, were screened for presence of RVFV neutralizing antibodies using the virus neutralization test (VNT). Sero-positivity rates of 1.87% (95% CI: 0.01%-6.9%) and 0.68% (95% CI: 0.49%-1.04%) were observed for warthogs and domestic pigs, respectively, but true prevalence rates, taking test sensitivity and specificity into account, were lower for both groups. There was a strong association between the results of the two groups (χ2 = 0.75, p = .38), and differences in prevalence between the epidemic and IEPs were non-significant for all suid samples tested (p > .05). This study, which provides the first evidence of probable exposure and infection of South African domestic pigs and warthogs to RVFV, indicates that further investigations are warranted, to fully clarify the role of suids in the epidemiology of RVF.

中文翻译：

---

南非家庭和野生土体中裂谷热的血清阳性率（1999-2016年）。

裂谷热（RVF）是一种由反刍动物，骆驼和人传播的病毒性疾病，其特征是动物广泛流产和新生儿死亡，以及类似流感的症状，可发展为人类肝炎和脑炎。该病是非洲，沙特阿拉伯和也门的地方病，暴雨过后或在支持RVF病毒（RVFV）感染的蚊媒繁殖的环境中爆发。RVFV的家养和野生动物维持宿主，在流行病期间（IEPs）可能是病毒来源，并导致零星的爆发，尽管报道表明非洲水牛（Syncerus caffer）可能发挥了作用，但仍未知角色。由于家猪和疣猪的栖息地分别与已知的家养和野生反刍动物RVFV维持宿主的栖息地非常接近，我们的研究通过评估RVFV暴露和猪粪中的血清转化来研究它们在南非RVF流行病学中的可能作用。使用病毒中和试验（VNT）分别筛选了来自南非2个省和所有9个省的总共107株疣猪和3984株家猪血清中是否存在RVFV中和抗体。疣猪和家猪的血清阳性率分别为1.87％（95％CI：0.01％-6.9％）和0.68％（95％CI：0.49％-1.04％），但考虑到测试的敏感性，真实的患病率和特异性方面，两组均较低。两组的结果之间有很强的相关性（χ2= 0.75，p = .38），对于所有测试的suid样本，流行病和IEP之间的患病率差异均无统计学意义（p> .05）。这项研究提供了南非家猪和疣猪可能接触和感染RVFV的第一个证据，该研究表明有必要进行进一步的研究，以充分阐明suids在RVF流行病学中的作用。