Human and livestock exposure to Rift Valley fever virus and Coxiella burnetii in Eastern Ethiopia: a One Health cross-sectional study.

BACKGROUND

Rift Valley fever (RVF) virus and Coxiella burnetii are high-priority zoonotic pathogens posing health and economic threats in Africa. Data from Ethiopia are limited. This study estimated the prevalence and associated factors of RVF virus and C. burnetii among humans and livestock in Eastern Ethiopia using a One Health approach.

METHODS

A multi-site cross-sectional study was conducted from May 1 to November 30, 2023, in the Shinile district, Somali Region, and Dire Dawa Administration. Data and blood samples were collected from 512 humans, and blood samples were collected from 1130 livestock. Sera and nucleic acids were tested using enzyme-linked immunosorbent assays (ELISA) and polymerase chain reaction (PCR), respectively. Logistic regression models were used to identify factors associated with RVF virus and C. burnetii IgG seropositivity.

RESULTS

Apparent RVF virus IgG seroprevalence was 5.1% (26/512) in humans and 7.8% (88/1130) in livestock, while C. burnetii Phase I and II IgG seroprevalence was 30.3% (155/512) and 32.9% (372/1130), respectively. Camels showed the highest seropositivity to RVF virus IgG (17.7%; 52/294) and C. burnetii Phase I and II IgG (39.5%; 116/294). Co-seropositivity was 1.8% (9/512) in humans and 3.7% (42/1,130) in livestock. All PCR tests were negative. Rift Valley fever virus IgG seropositivity was associated with handling aborted materials (OR = 3.7; 95% CI 1.4-9.6; p = 0.007) and high mosquito abundance (OR = 4.5; 95% CI 2.0-10.1; p < 0.001). Camels had the highest odds of RVF virus IgG seropositivity (OR = 8.0, 95% CI 3.5-18.2; p < 0.001). Human C. burnetii Phase I and II IgG seropositivity was associated with female sex (OR = 2.4; 95% CI 1.6-3.6; p < 0.001), raw milk consumption (OR = 2.2; 95% CI 1.4-3.5; p < 0.001), cohabitation with animals (OR = 1.7; 95% CI 1.1-2.5; p = 0.01), and handling animal carcasses (OR = 2.3; 95% CI 1.4-3.5; p < 0.001).

CONCLUSIONS

The seroprevalence of RVF virus was low, whereas the seroprevalence of C. burnetii was high. High camel seropositivity underscores their role in pathogen transmission. One Health surveillance and targeted interventions are recommended to control the risk of future outbreaks.