Seroprevalence and regional risk assessment of bluetongue virus among livestock in Central Saudi Arabia.

Background and aim: Bluetongue virus (BTV), an arbovirus of major economic importance, affects domestic and wild ruminants globally and is primarily transmitted by Culicoides biting midges. The virus is endemic in many regions, yet limited data are available for Saudi Arabia. This study aimed to determine the seroprevalence of BTV antibodies in cattle, goats, sheep, and camels across two ecologically distinct regions in central Saudi Arabia and to assess species- and region-specific risk profiles.

Materials and methods: A total of 1,194 serum samples were collected from apparently healthy livestock (280 cattle, 159 camels, 429 sheep, and 326 goats) in Riyadh and Al-Qassim between October 2023 and March 2024. Samples were tested for BTV antibodies using a commercial competitive enzyme-linked immunosorbent assay. Statistical analysis included Chi-square tests and odds ratios with 95% confidence intervals to compare prevalence rates between species and regions.

Results: The overall BTV seroprevalence was 44.6% (533/1,194). Goats had the highest prevalence (59.8%), followed by cattle (51%), sheep (36.3%), and camels (22.6%). In Riyadh, cattle (55.7%) and goats (55%) showed the highest rates, while in Al-Qassim, goats (65.7%) were most affected. Camels consistently showed the lowest seroprevalence (18.6%-25%). Statistically significant differences in seroprevalence were observed among species and between regions (p < 0.05).

Conclusion: BTV is endemic in central Saudi Arabia, with substantial species and regional variability. Goats and cattle are at higher risk, indicating a need for species-targeted surveillance and vector control. The findings support the implementation of national bluetongue monitoring strategies and lay the groundwork for future molecular and longitudinal studies.