Seroepidemiological Survey of Rift Valley Fever Virus in Ruminants in Garissa, Kenya

Introduction: Rift Valley fever (RVF) is a vector-borne zoonotic disease caused by phlebovirus in the family Bunyaviridae . In Kenya, major outbreaks occurred in 1997–1998 and 2006–2007 leading to human deaths, huge economic losses because of livestock morbidity, mortality, and restrictions on livestock trade. Aim: This study was conducted to determine RVF seroprevalence in cattle, sheep, and goats during an interepidemic period in Garissa County in Kenya. Methods: In July 2013, we performed a cross-sectional survey and sampled 370 ruminants from eight RVF-prone areas of Garissa County. Rift Valley fever virus (RVFV) antibodies were detected using a multispecies competitive enzyme-linked immunosorbent assay. Mixed effect logistic regression models were used to determine the association between RVF seropositivity and species, sex, age, and location of the animals. Results: A total of 271 goats, 87 sheep, and 12 cattle were sampled and the overall immunoglobulin G seroprevalence was 27.6% (95% CI [23–32.1]). Sheep, cattle, and goats had seroprevalences of 32.2% (95% CI [20.6–31]), 33.3% (95% CI [6.7–60]), and 25.8% (95% CI [22.4–42]), respectively. Seropositivity in males was 31.8% (95% CI [22.2–31.8]), whereas that of females was 27% (95% CI [18.1–45.6]). Conclusions: The high seroprevalence suggests RVFV circulation in domestic ruminants in Garissa and may be indicative of a subclinal infection. These findings provide evidence of RVF disease status that will assist decision-makers to flag areas of high risk of RVF outbreaks and prioritize the implementation of timely and cost-effective vaccination programs.