Copulation of Ixodes ricinus males and females on the host and its potential impact on pathogen transmission.

Abstract

The common tick Ixodes ricinus is one of Europe's most important vectors of tick-borne diseases. The increased risk of attacks by this tick suggests the need for identification of factors contributing to the transmission of tick-borne pathogens, and the routes of pathogen circulation in nature. Polymerase chain reaction was used to investigate the prevalence of four pathogens, i.e. Borrelia burgdorferi s.l. (Bb), Anaplasma phagocytophilum (Ap), Babesia spp. (Bs), and Bartonella spp. (Ba) in I.ricinus females and males mating on dogs in south-central Poland. The study revealed the presence of three pathogens: Bb, Ap, and Bs in 9.4%, 5.4%, and 5.4% of all I.ricinus adults in copula, respectively. Co-infection with two pathogens was detected in one tick specimen. Borrelia burgdorferi spirochetes were isolated in two females and two males in copula, but the sexual transfer of the spirochetes between these specimens could not be clearly confirmed. By increasing the feeding dynamics in females, the copulation of I.ricinus males with females attached to the host's skin may stimulate pathogen replication in tick tissues and migration from the gut to the salivary glands. Further investigations of the I.ricinus copulation on the host on female feeding and pathogen transmission may contribute to the elucidation of the eco-epidemiology of tick-borne diseases transmitted by this tick species.