Ticks and Coxiella burnetii exposure in one-humped camels (Camelus dromedarius) in Maiduguri, northeastern, Nigeria

Ticks are obligatory hematophagous arachnids, and vectors for a wide array of pathogens. Coxiella burnetii is the causative agent of Q fever, a highly contagious zoonotic disease of worldwide public health importance and infects not only mammals but also arthropods, particularly ticks. This pathogen has been detected in ticks, and causes subclinical infections in livestock. It may be responsible for reproductive failure and abortions in dromedary camels ( Camelus dromedarius ) in semi-arid regions. Information on the occurrence of C. burnetii in Nigeria is scarce. Hence, this study on slaughtered dromedary camels was conducted to determine the diversity of tick species and the prevalence of C. burnetii IgG antibodies in camels as well as to identify related risk factors in Maiduguri, Borno State, Nigeria. Ticks ( n = 1353) and blood samples ( n = 300) were collected from camels. Ticks were identified using standard morphological keys. All serum samples were analyzed for C . burnetii -specific IgG antibodies using a commercial indirect enzyme-linked immunosorbent assay (ELISA) test kit. The obtained results were subsequently analyzed using descriptive (percentages) and inferential (Chi-square and logistic regression) statistical tools. Of the 300 camels examined, 272 were infested with ticks, with an overall prevalence of 90.67%. The 1,353 ticks collected belong to seven different species including Hyalomma ( Hy ) dromedarii ( n = 562; 41.54%), Hy. rufipes ( n = 237; 17.52%), Hy. impeltatum ( n = 318; 23.50%), Hy. truncatum ( n = 213; 15.74%) Hy. impressum ( n = 10; 0.74%), Amblyomma variegatum ( n = 10; 0.74%) and Rhipicephalus evertsi evertsi ( n = 3; 0.22%). The overall seroprevalence of C. burnetii IgG antibodies in camels was 42.3% (127/300), with a slightly higher seropositivity in female camels, with 42.9% (78/182), than in males, with 41.5% (49/118) ( p > 0.05). Regression analysis showed that female camels were three times more likely (OR = 3.184; 95% CI: 0.281–36.051) to be seropositive than male camels. A statistically significant association ( p < 0.05) was observed with age, with the highest seroprevalence of C. burnetii IgG antibodies of 44.4% (79/178) in 3.5–6 years old camels compared to other age categories. The logistic regression analysis revealed a 1.2 times higher (OR = 1.271; 95% CI: 0.575–2.807) likelihood of seropositivity when ticks were present on the host. This study confirmed a moderate seroprevalence of C. burnetii IgG antibodies among camels in Maiduguri, Nigeria. Some tick species, known as competent vectors of C. burnetii , were also found infesting camels in the study area. The use of appropriate control measures to reduce the burden of ticks and transmission of infection is advised.