Identification of Ixodes holocyclus by DNA sequencing: Application for suspected tick envenomation in a dog living outside an enzootic area

This report describes the use of DNA sequencing to identify Ixodes holocyclus as the cause of suspected tick paralysis in a dog that lived outside an enzootic area. The dog had not recently visited a known enzootic area or a predicted core area for this species of tick. Species differentiation of paralysis ticks, I. holocyclus and I. cornuatus can be difficult. The use of DNA sequences to definitively identify the species of tick causing paralysis in Victoria will allow new information to be gained about the distribution of I. holocyclus and I. cornuatus and assist in identifying differences in clinical disease caused by these species. This case also serves as a reminder that vector-borne diseases should be considered as a differential diagnosis despite the animal living outside a known enzootic area.