Real time PCR identification of Ixodes holocyclus from imported cats and associated health risks

Background: Ticks are ectoparasites of major veterinary and medical importance due to their capacity to vector numerous pathogens. Bacterial, viral, and protozoan diseases that affect livestock and companion animals can cause economic losses and reduce productivity. To protect animal health, ensure food safety, and reduce the incidence of tick-borne disease in humans, effective surveillance and integrated control of ticks are essential.

The objective of this article was to employ morphological identification and molecular techniques to detect and confirm Ixodes holocyclus ticks infesting imported domestic cats.

A study of a total of 100 imported domestic cats from importers, which were brought to the veterinary clinic for regular check-ups. Under a stereomicroscope, ticks were identified by their morphology and using standard taxonomic keys. DNA obtained from every individual tick sampled was examined by targeting tick-specific gene markers through conventional PCR. Real-time PCR detects and confirms the types of tick species and their associated pathogens in their natural habitats.

The results of morphological identification revealed the presence of the tick in 18 out of 100 cats (18%), exhibiting the morphological characteristics of the I. holocyclus. The positive samples were then identified as isolates using conventional PCR based on the cox1 mitochondrion. The cox1 gene had Ct values of 18.00 to 18.30; for EF1-α, it was around 21.49 to 21.55, and thus consistent. The melt curve data of both genes produced a single peak, indicating the high specificity of the assay. A phylogenetic analysis of the 18 sequenced isolates based on partial mitochondrial COX1 gene sequences showed four clusters. The largest cluster was comprised of 11 isolates that were closely related to OQ675411.1 (Ixodes holocyclus isolate H1). Overall, the isolates were confirmed as Ixodes holocyclus, with minor differences.

The real-time PCR method was able to detect Ixodes holocyclus ticks with speed, accuracy, and 100% specificity. Ticks can infest cats, allowing them to carry these parasites into both the house and the environment. This also raises the risk of transmission, including zoonotic transmission. Furthermore, this can also pose a public health hazard.