Ticks and tick-borne pathogens (TBPs) are major constraints to camel health and production, yet epidemiological data on their diversity and impact on dromedary camels are limited. We sur-veyed the diversity of ticks and TBPs associated with camels and co-grazing sheep at 12 sites in Marsabit County, northern Kenya. We screened blood and ticks (858 pools) collected from 296 camels and 77 sheep for bacterial and protozoan TBPs by high-resolution melting analysis and sequencing of PCR products. Hyalomma (75.7%), Amblyomma (17.6%) and Rhipicephalus (6.7%) spp. ticks were morphologically identified and confirmed by molecular analyses. We detected TBP DNA in 80.1% of blood samples from 296 healthy camels. “Candidatus Anaplasma camelii”, “Candidatus Ehrlichia regneryi” and Coxiella burnetii were detected in both camels and associ-ated ticks, and Ehrlichia chaffeensis, Rickettsia africae, Rickettsia aeschlimannii and Coxiella endo-symbionts were detected in camel ticks. We also detected Ehrlichia ruminantium, responsible for heartwater disease in ruminants, in Amblyomma ticks infesting camels and sheep and in sheep blood, indicating its endemicity in Marsabit. Our findings also suggest that camels and/or the ticks infesting them are reservoirs of zoonotic Q fever (C. burnetii), ehrlichiosis (E. chaffeensis), and rickettsiosis (R. africae), which pose a public health threat to pastoralist communities.

Rickettsia and Coxiella burnetii are zoonotic tick-borne pathogens that can cause febrile illnesses with or without other symptoms in humans but may cause subclinical infections in animals. There are only a few reports on the occurrence of these pathogens in cattle and water buffaloes in Southeast Asia, including the Philippines. In this study, molecular detection of Rickettsia spp. and C. burnetii in the blood and Rhipicephalus (Boophilus) microplus ticks of cattle and water buffaloes from five provinces in Luzon Island of the Philippines was done. A total of 620 blood samples of cattle and water buffaloes and 206 tick samples were collected and subjected to DNA extraction. After successful amplification of control genes, nested PCR was performed to detect gltA of Rickettsia and com1 of C. burnetii. No samples were positive for Rickettsia while 10 (cattle – 7, water buffaloes - 3) or 1.6% of blood and 5 or 1.8% of tick samples were C. burnetii-positive. Sequence analysis of the positive amplicons showed 99-100% similarity to reported C. burnetii isolates. This molecular evidence on the occurrence of C. burnetii in Philippine ruminants and cattle ticks and its zoonotic nature should prompt further investigation and surveillance to facilitate its effective control.

This study was conducted to investigate the prevalence of Coxiella burnetii infection according to cattle breeds and growth types. A total of 491 cattle [cattle breed: 216 dairy cattle and 275 beef cattle; according to growth type: indoor housing (n = 294) and grazing (n = 197)] were tested for the presence of C. burnetii DNA and antibodies against C. burnetii using a commercial enzyme-linked immunosorbent assay (ELISA). Overall, 10.8% and 8.8% of the cattle were positive by PCR and for C. burnetii antibodies, respectively. The prevalence of C. burnetii was significantly higher in beef cattle than in dairy cattle using PCR (13.6% vs 7.4%; P = 0.032) and ELISA (14.6% vs 1.4%; P = 0.000), respectively. The overall infection rate of C. burnetii was significantly high in grazing cattle (PCR: 24.9%, ELSIA: 21.3%; P = 0.000) compared with housing cattle (PCR: 1.4%, ELISA: 0.3%). The results indicate that beef cattle have a significantly higher risk of contracting C. burnetii infection compared with dairy cattle (21.5% vs. 7.9%, χ2 = 5.82, P = 0.000, odds ratio = 3.197, 95% CI: 1.80-5.67). In addition, the infection of C. burnetii was significantly associated with grazing (P = 0.000). Moreover, a risk of contracting C. burnetii infection in grazing cattle was increased by 32.57-fold (95% CI: 12.84-82.60, P = 0.000) compared with indoor housed cattle. The phylogenetic analysis based on the IS111 gene revealed that our isolates were grouped together with humans, ticks, goats, and cattle isolates found in several countries. C. burnetii isolates circulating in the Republic of Korea exhibit genetic variations. Consequently, our results suggest that cattle are potential reservoirs for C. burnetii infection and most importantly, grazing acts as a high risk factor for the occurrence and transmission of this infection.

Infective endocarditis is a rare and challenging diagnosis, Q fever endocarditis being a major cause of culture-negative endocarditis (IE). The presence of multiple cerebral microbleeds (CMBs) suggests a particular vascular frailty and could be correlated to potential emergence of a haemorrhagic stroke in IE. We report a case of a 45 years-old patient with Coxiella burnetii endocarditis, with a brainstem hemorrhage and cerebral MRI CMBs resembling those of CAA. However the systemic inflammatory tests, the splenic infarct and kidney pathology could not be explained by a variant of CAA, neither the normal initial cerebral CT scan when the patient had already the brainstem clinical signs without evidencing the hemorrhage. Transthoracic and transesophageal echocardiogram revealed only calcified bicuspid aortic valve with moderate stenosis and regurgitation, without any vegetations and the blood cultures on conventional media were negative. Serology for Coxiella burnetii was positive. Inclusion of CMBs as a new minor imaging criteria for infective endocarditis could upgrade the diagnosis in almost 50% of patients.

It was the aim of this study to examine whether the usage of the vaccine COXEVAC® (Ceva Santé Animale) could reduce the consumption of antibiotics in Q-fever-positive dairy farms. Additionally, the effects of other herd-level factors on the consumption of antibiotics were investigated. In this longitudinal cohort study, 36 farms with vaccination and 13 farms without vaccination participated. In all herds, Coxiella burnetii had been directly or indirectly diagnosed. To compare the treatment frequency of antibiotics between the vaccinated group and the non-vaccinated group, the consumption of antibiotics for each farm was collected using the veterinary documents about the application and delivery of antibiotics. To gather detailed information about herd data, nutrition, milking management, housing, and animal health, the farmers were interviewed with the help of a questionnaire. The results suggest that there might be an association between the vaccination against Q fever and a reduced consumption of antibiotics. Neither herd size nor milk yield level influenced the consumption of antibiotics in the study herds. Type of flooring and udder cluster disinfection while milking were associated with a lower and higher therapy frequency, respectively. Further studies are necessary to elucidate the cause-effect relationship between vaccination and the consumption of antibiotics.