Seroepidemiological study of Rift Valley fever (RVF) in animals in Saudi Arabia.

Area of Science:

• Veterinary Virology
• Epidemiology
• Zoonotic Disease Surveillance

Background:

• Rift Valley fever virus (RVFV) poses a significant threat to livestock and public health.
• Previous outbreaks, notably in Saudi Arabia's southwestern region in 2000, underscore the need for continuous monitoring.
• Vaccination practices vary regionally, necessitating serological surveillance in non-vaccinated areas.

Purpose of the Study:

• To determine the serological prevalence of IgG antibodies against RVFV in livestock in non-vaccinated regions of Saudi Arabia.
• To assess the potential circulation of RVFV outside of known outbreak zones.
• To inform future disease control and surveillance strategies.

Main Methods:

• Serological investigation using IgG-sandwich ELISA across sheep, goats, and cattle.
• A non-species-specific ELISA was employed for camel sera.
• A total of 3,480 unvaccinated animals were randomly sampled from 22 localities in five regions.

Main Results:

• An extremely low seroprevalence of RVFV IgG antibodies was detected (0.002%).
• Only seven out of 3,480 animals tested positive: four sheep and three goats.
• No clinical signs of RVFV infection or evidence of virus activity were observed in the studied populations.

Conclusions:

• The minimal seropositivity suggests limited RVFV circulation in the surveyed non-vaccinated areas.
• The rare positive results are likely attributable to false positives or smuggled vaccinated animals.
• Continuous monitoring of livestock, both within and outside historical outbreak zones, is crucial for early detection and prevention of RVFV.