Rift Valley fever seropositivity in humans and domestic ruminants and associated risk factors in Sengerema, Ilala, and Rufiji districts, Tanzania

Sindato, Calvin; Karimuribo, Esron D.; Vairo, Francesco; Misinzo, Gerald; Rweyemamu, Mark M.; Hamid, Muzamil Mahdi Abdel; Haider, Najmul; Tungu, Patrick K.; Kock, Richard; Rumisha, Susan F.; Mbilu, Togolai; Ntoumi, Francine; Zumla, Alimuddin; Mboera, Leonard E.G.

Abstract

Objectives
Data on Rift Valley fever virus (RVFV) prevalence in urban settings and pastoral areas of Tanzania are scarce. We performed a cross-sectional study of RVFV seroprevalence and determinants in humans and animals from Ilala, Rufiji, and Sengerema districts of Tanzania.

Methods
Blood samples from the study participants were tested for anti-RVFV immunoglobulin G (IgG) antibodies using an enzyme-linked immunosorbent assay. Logistic regression was used to determine association between exposure risk practices and RVFV seropositivity.

Results
The study involved 664 humans, 361 cattle, 394 goats, and 242 sheep. The overall anti-RVFV IgG seroprevalence in humans and animals was 2.1% (95% confidence interval [CI] 0.01-0.04) and 9.5% (n = 95, 95% CI 0.08-0.12), respectively. Seroprevalence in humans in Rufiji, Ilala, and Sengerema was 3.0% (n = 225, 95% CI 0.01-0.06), 1.8% (n = 230, 95% CI-0.005- 0.04), and 1.4% (n = 209, 95% CI 0.01-0.04), respectively (P >0.05). Seroprevalence in animals in Sengerema, Rufiji, and Ilala was 12.1% (n = 40, 95% CI 0.09-0.16), 11.1% (n = 37, 95% CI 0.08-0.15), and 5.4% (n = 18, 95% CI 0.03-0.08), respectively (P = 0.006). Handling of carcasses increased the odds of RVFV seropositivity 12-fold (odds ratio 11.84, 95% CI 1.97-71.16).

Conclusion
The study confirms previous occurrence of RVFV in multiple species in the study districts. Animal handling practices appear to be essential determinants of seropositivity.

Citation

Sindato, C., Karimuribo, E. D., Vairo, F., Misinzo, G., Rweyemamu, M. M., Hamid, M. M. A., …Mboera, L. E. (2022). Rift Valley fever seropositivity in humans and domestic ruminants and associated risk factors in Sengerema, Ilala, and Rufiji districts, Tanzania. International Journal of Infectious Diseases, 122, 559 - 565. https://doi.org/10.1016/j.ijid.2022.07.012

• Journal Article Type: Article
• Acceptance Date: Jul 3, 2022
• Online Publication Date: Jul 8, 2022
• Publication Date: 2022-09
• Publicly Available Date: May 30, 2023
• Journal: International Journal of Infectious Diseases
• Print ISSN: 1201-9712
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 122
• Pages: 559 - 565
• DOI: https://doi.org/10.1016/j.ijid.2022.07.012
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S1201971222004039?via%3Dihub