DIVERSITY AND DNA BARCODING OF IXODIDAE AND ARGASIDAE TICKS IN THE US-MEXICO BORDER REGION OF THE MUNICIPALITY OF JUAREZ, CHIHUAHUA

Abstract

Ticks are the most important arachnids for human and animal health because they are vectors of a plethora of disease-causal agents, including bacteria and arboviruses. In the border municipality of Juarez, Chihuahua, severe cases of human rickettsiosis and a high prevalence of bacteria transmitted by ticks in domestic animals have been reported in recent years. Inadequate morphological identification due to similarity between morphospecies or identification of juvenile stages is a common problem of the prevention and control programs. As a result, DNA barcode technology is a reliable support tool for completing the morphological identification of ticks at the border between Mexico and the United States. This study reports the diversity and DNA barcode of Ixodidae (hard) and Argasidae (soft) ticks collected between 2018-2022 along this Mexican border municipality. Based on morphology and confirmed species identity using DNA barcoding, 3245 ticks belonging to four species were collected along Juarez municipality in Chihuahua, state. Ticks were identified as Rhipicephalus sanguineus, Dermacentor albipictus, Otobius megnini, and Argas persicus. A Bayesian analysis was constructed with a sample of 65 Cytochrome Oxidase subunit I mitochondrial sequences of the ticks collected. The topology of Bayesian tree displayed tree groups of R. sanguineus, whereas the clades of other species were well-defined. The Markov model of nucleotide substitution for distance estimation show a mean (±SE) of 18 (±1.0) %. The intraspecific distance ranged between 0 to 0.02 %, whereas the interspecific distance was reached 11.9 to 29.5 %. Dogs were the major host of Rh. sanguineus, whereas O. megnini were predominant mostly on cows and horses. A. persicus were collected on soil, and D. albipictus were collected only on one deer. Finally, the public health importance of these species from the perspective of the public health of transboundary United States-Mexico region is also discussed.