Application of non-destructive DNA extraction for the molecular and morphological identification of tick species and their pathogens

Tick-borne diseases remain a major concern in both human and animal health in most biogeographical regions. Since certain tick-borne pathogens are transmitted by specific tick species, tick identification through morphological and biomolecular examination of the species is highly recommended for investigation of tick-borne diseases. In this study, we assessed a non-destructive DNA protocol for identifying tick species and screening of pathogens and evaluate the effects of this protocol on the tick body, using geometric morphometric (based on coxa 1). Overall, 80 Ixodes spp. specimens (I. ricinus, I. hexagonus, and I. acuminatus) conserved in alcohol for more than 15 years were tested here, including all stages (male, female, nymph and larva). Molecular investigation using 16S rRNA enabled 92% of ticks to be assigned to a species. The microfluidic chip demonstrates the presence of Bartonella sp. (13%), Rickettsia helvetica (63%) and Hepatozoon sp. (13%) in tested engorged females. Comparison of the coxa 1 shape before and after extraction showed no changes in morphology. We demonstrated that DNA can be extracted from old specimens of hard ticks using non-destructive methods, allowing for molecular identification of ticks and pathogens without altering their morphology. As a result, this technique makes it possible to preserve specimens from laboratory or museum collections. Additionally, non-destructive DNA extraction could be useful in medical entomology for monitoring arrivals of alien species and emergence of associated tick-borne diseases affecting humans, domestic animals, or wildlife.