Studies across Africa and Asia indicate that more than one-third of camels are exposed to Coxiella burnetii, the bacterium responsible for Q fever, according to a recent systematic review and meta-analysis. This review analyzed data from 35 studies involving 11,233 camels, revealing an overall prevalence rate of 33.37%, with a range of 23.14% to 45.44% reported. Among the animals tested, 4,363 showed positive results for the pathogen through either antibody detection or molecular testing.
Q fever, also known as coxiellosis, affects a wide range of hosts, including humans, livestock, and various wildlife species. Domestic animals such as cows, goats, sheep, and camels are primary reservoirs for the bacteria. The pathogen is particularly infectious, requiring as few as one to ten organisms to lead to an infection in humans through inhalation of contaminated air. Infected animals release the bacterium in high quantities through various means, such as through birth and lactation, which enhances the risk of transmission. The first documented occurrence of Q fever in camels was reported in the 1950s, yet ongoing limited surveillance has hindered a complete understanding of its prevalence.
The research team utilized the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines to structure their search across several databases, including PubMed and Scopus, for studies published between January 1, 2000, and November 30, 2025. Rigorous screening ensured that every included study met the necessary criteria for sample size and diagnostic methods, achieving moderate to high methodological quality.
The analysis highlighted significant variability among studies. Cochran’s Q test indicated substantial genuine differences in prevalence rates, while the statistical synthesis revealed a wide prediction interval of 3.55% to 87.20%. A random-effects model was employed due to the considerable heterogeneity found in the data. The pooled estimate remained stable through sensitivity checks, landing at a similar prevalence rate of 33.90%.
Geographic data revealed that 65.7% of eligible studies were conducted in Africa, while the remaining 34.3% were in Asia. Although Africa exhibited a numerically higher pooled prevalence at 37.17% compared to 26.87% in Asia, the difference was not statistically significant. Variation existed between countries, ranging from 8.67% in Iran to 80.28% in Chad.
The diagnostic methods used in the studies highlighted differing results; enzyme-linked immunosorbent assays (ELISA) indicated a seroprevalence of 44.06%, while polymerase chain reaction (PCR) results showed only 7.76%. This discrepancy may stem from the higher number of animals tested with ELISA and the biological characteristics of the assays.
Among studies reporting risk factors, female camels were found to have significantly higher odds of Q fever, and camels with tick infestations were also at increased risk. The authors note that these findings point to major zoonotic concerns regarding Q fever in camel-raising regions of Africa and Asia. They emphasize that the evidence base primarily reflects studies from these two continents and suggest strengthening surveillance and standardizing diagnostic approaches to better characterize the prevalence of C. burnetii in camel populations.
