Nationwide serological, molecular, and spatial assessment of Q fever in dromedary camels (Camelus dromedarius) in Jordan: A One Health perspective.

BACKGROUND AND AIM: Q fever, caused by Coxiella burnetii, is a globally distributed zoonosis with major public health and livestock production implications. Dromedary camels (Camelus dromedarius) are increasingly recognized as important reservoirs, particularly in arid and semi-arid regions. In Jordan, however, comprehensive national-level data integrating serology, molecular detection, and spatial epidemiology are lacking. This study aimed to estimate the serological and molecular prevalence of Q fever in camels, identify associated risk factors, and describe the spatial distribution of infection across Jordan.

MATERIALS AND

METHODS

A nationwide cross-sectional study was conducted between July and October 2022 using a two-stage cluster sampling design. A total of 468 camels from 31 villages across all camel-rearing governorates were sampled. Serum samples were tested for anti-C. burnetii antibodies using a commercial indirect multi-species enzyme-linked immunosorbent assay, while whole blood was examined for C. burnetii DNA using conventional polymerase chain reaction (PCR) assays targeting IS1111 and CB-1 genes. Survey-weighted prevalence estimates were calculated, and risk factors were evaluated using univariate and multivariate survey-weighted logistic regression. Spatial distribution was mapped at the governorate level.

RESULTS

The weighted prevalence of Q fever was 88.75% (95% confidence interval: 79.26%-98.23%) using parallel interpretation of serological and molecular tests. Individually, prevalence was 44.02% by enzyme-linked immunosorbent assay and 68.93% by PCR. Significant risk factors included age ≥3 years, contact with other camel herds, Sofor breed, light or absent tick infestation, and improper disposal of abortion materials. Co-herding with other species and a history of abortion were associated with reduced odds of positivity. Marked spatial heterogeneity was observed, with the highest prevalence in Tafilah governorate and the lowest in Zarqa.

CONCLUSION

This first nationwide, integrated serological, molecular, and spatial study demonstrates an exceptionally high burden of Q fever in Jordanian camels, highlighting their critical role as a reservoir. The findings underscore the urgent need to incorporate camels into national Q fever surveillance and control programs within a coordinated One Health framework involving animal, human, and environmental health sectors.