Microbiome of Hyalomma dromedarii (Ixodida: Ixodidae) Ticks: Variation in Community Structure with Regard to Sex and Host Habitat

Abstract

Hyalomma dromedarii ticks are the main hematophagous ectoparasites of camels, harboring a variety of microbes that can affect tick vector competence and pathogen transmission. To better understand the tick microbiome influenced by sex and host habitat, we analyzed the bacterial community of H. dromedarii male and female ticks collected from camel farms, livestock markets, and slaughterhouses, representing the range of major habitats in the UAE, by sequencing the 16S rRNA gene. Tick samples were collected during 2022 and 2023. A total of 40 ticks (male (15), female (15), and nymph (10)) were selected from tick samples collected from camels and processed for genomic DNA and next-generation sequencing using the Illumina MiSeq platform. We obtained 151,168 read counts, and these formed 237 operational taxonomic units representing 11 phyla, 22 classes, 77 families, and 164 genera. The phyla Actinomycetota, Bacillota, Bacteroidota, Pseudomonadota, and Fusobacteriota were the most abundant. The bacterial genus Corynebacterium dominated the microbiomes of farm-collected female H. dromedarii ticks, while Proteus dominated the microbiomes of farm-collected male H. dromedarii ticks. In comparison, the microbiomes of H. dromedarii ticks collected from slaughterhouse samples were dominated by genus Francisella in both males and females. Our results confirm that the bacterial microbiomes of H. dromedarii ticks vary by sex and habitat settings. Furthermore, recent findings could deliver insight into the differences in the ability of camel ticks to acquire, maintain, and transmit pathogens in various habitats that may impact the tick vector competence of medically and agriculturally important species in the Middle East and North Africa (MENA) region and Asia.