Camels represent an important resource for inhabitants of the most arid regions of the world and their survival is mainly related to environment conditions including the risk of parasitic diseases, which may represent a significant cause of losses in livestock production of these areas. Camels may be parasitized by several hematophagous arthropods, which can be vectors of several diseases including zoonosis. This study aimed to investigate in dromedary camels and their ticks the importance of tick-borne hemoparasites that might be responsible for a recent and obscure morbidity of camels in Al Dhafra region of Abu Dhabi, UAE. Blood samples and ticks from 93 naturally infected camels belonging to 36 herds, affected by variable acute clinical syndromes lasting from 3 to 5 days, were analyzed through molecular techniques for specific DNA presence of different blood pathogens: Anaplasmamarginale/Anaplasmaovis, Anaplasma phagocytophilum, Coxiella burnetii,Babesia spp., and Theileria spp. DNA. All the 72 ticks collected belonged to the Hyalomma dromedarii species and were negative for blood pathogens. n = 15 camels (16.1%) were found positive to the following tick-borne hemoparasites: A. phagocytophilum 11 (11.8%), Coxiella burnetii 3 (3.2%), and Babesia/Theileria spp. 2 (2.1%). One singular camel showed coinfection of C. burnetii and A. phagocytophiulm. Genetic profile of C. burnetii showed a high phylogenetic relatedness to European, Asian and African C. burnetii strains. This is the first laboratory investigation on tick-borne pathogens in camels in UAE, and the first report of A. phagocytophilum and C. burnetii. Moreover, since the detected pathogens are recognized pathogens for humans, this study highlights the zoonotic risk for humans working in camel husbandry.

Trypanosomosis is an important disease of dromedary camels caused by the pathogenic protozoan Trypanosoma evansi. This study aimed to compare three different tests for its diagnosis in this species: conventional microscopy, the card agglutination test for trypanosomosis/T. evansi (CATT/T. evansi) and real-time PCR. Whole blood and serum samples collected from 77 dromedary camels of Abu Dhabi, United Arab Emirates, were analysed with the test methods stated. Statistical analysis was done using McNemar’s chi-squared test, and Cohen’s kappa index (κ) was calculated. We obtained results with positivity of 18% (14/77) by microscopy, 22% by CATT (17/77) and 60% (46/77) by real-time PCR, with the chain reaction detecting at a respectively three- and two-fold greater rate than the other techniques. Analysis of the data revealed a relative sensitivity of 30.4% and 37.0% for microscopy and CATT, respectively, compared to real-time PCR. The difference between the real-time PCR’s sensitivity and those of the other methods was statistically significant, with X² values of 30.03 and 20.1, respectively (df = 1 and P = 0.05 in both cases). Agreement of microscopy results with those of with CATT was good (κ = 0.72; 95% CI = 0.62–0.82). Cohen’s kappa index showed fair agreement of real-time PCR with microscopy (κ = 0.26; 95% CI = 0.16–0.36) whereas it was in poor agreement with CATT (κ = 0.09; 95% CI = 0.02–0.15). Real-time PCR was found to be more sensitive than microscopy and CATT.

Wild animals play a critical role in maintenance and transmission of various tick-borne pathogens. It is essential to identify these wild host species that can serve as important reservoirs of tickborne diseases. In the present study we investigated Dama gazelle (Nanger dama) as a potential novel reservoir of Theileria spp. A total of 53 blood samples collected from Dama gazelle as part of the Al Ain Zoo preventive medicine program were screened for Theileria spp. by qPCR using a commercial assay, followed by additional studies using conventional PCR targeting an approximate 450-base pair (bp) fragment of the V4 hypervariable region of the 18S ribosomal RNA (rRNA) gene. Sequencing and phylogenetic analysis of a subset (20) of PCR amplicons revealed Theileria isolates from gazelles of Al Ain Zoo clustered closely to Theileria sp. Dama Gazelle (AY735115) from USA and were far away or did not cluster with the known Theileria spp. of ruminants namely T. annulata, T. ovis, T. orientalis, T. luwenshuni, T.parva and T.sinensis. Theileria genotypes detected in gazelles of present study were clearly distinct from the other common theileria species of ruminants. The present finding throws light on the critical role of reservoir host in maintenance and transmission of pathogen.

The recent emergence of anaplasmosis in camels has raised global interest in the pathogenicity and zoonotic potential of the pathogen causing it and the role of camels as reservoir hosts. In the United Arab Emirates (UAE), molecular studies and genetic characterization of camel-associated Anaplasma species are limited. This study aimed to characterize molecularly Anaplasmataceae strains circulating in dromedary camels in the UAE. Two hundred eighty-seven whole-blood samples collected from dromedary camels across regions of the Abu Dhabi Emirate were received between 2019 and 2023 at the Abu Dhabi Agriculture and Food Safety Authority (ADAFSA) veterinary laboratories for routine diagnosis of anaplasmosis. The animals were sampled based on field clinical observation by veterinarians and their tentative suspicion of blood parasite infection on the basis of similar clinical symptoms as those caused by blood parasites in ruminants. The samples were screened for Anaplasmataceae by PCR assay targeting the groEL gene. Anaplasmataceae strains were further characterized by sequencing and phylogenetic analysis of the groEL gene. Thirty-five samples (35/287 = 12.2%) tested positive for Anaplasmataceae spp. by PCR assay. Nine positive samples (9/35 = 25.7%) were sequenced using groEL gene primers. GenBank BLAST analysis revealed that all strains were 100% identical to the Candidatus A. camelii reference sequence available in the GenBank nucleotide database. Phylogenetic analysis further indicated that the sequences were close to each other and were located in one cluster with Candidatus A. camelii sequences detected in Saudi Arabia, Morocco, and the UAE. Pairwise alignment showed that the UAE sequences detected in this study were completely identical and shared 100% identity with Candidatus A. camelii from Morocco and Saudi Arabia and 99.5% identity with Candidatus A. camelii from the UAE. This study demonstrates the presence of Candidatus A. camelii in UAE dromedary camels. Further critical investigation of the clinical and economical significance of this pathogen in camels needs to be carried out.

The resistance status in Hyalomma ticks collected from animal farms in three different regions of the Emirate of Abu Dhabi (UAE) was estimated using adult immersion tests with various concentrations of cypermethrin (50ppm, 100 ppm, 200 ppm, 400ppm and 800 ppm). Regression graphs of tick mortality plotted against cypermethrin concentrations were utilized to determine lethal concentrations (LC50 and LC90). The data generated on different life history variables (mortality, egg mass weight, reproductive index, and percent inhibition of oviposition) were used to assess the resistance status. Results revealed level III cypermethrin resistance in Hyalomma anatolicum of the Al Hamam region (Al Ain) and level II resistance in the Malaqet region (Al Ain), whereas level I resistance was observed in the other studied locations, except Sweihan (Al Ain) where the tick population was fully susceptible. The LC90 value of susceptible (Sweihan) H. anatolicum was 244.87ppm and the discriminating dose (DC) was calculated to be 489.74ppm. The present study is the first report of cypermethrin resistance in ticks of the United Arab Emirates and highlights the need to further monitor resistance evolution during the implementation of tick control programs.