Monitoring causative agents of tick-borne infections in Primorsky Krai (2014-2018)

Abstract

Objective. In the last decade, along with tick-borne encephalitis new previously unknown infections began to occur after tick bites in all regions of ixodid ticks. In the Primorsky Krai, studies in this direction began in 2014. The aim of this study was to assess evaluation of infestation by pathogens of tick-borne infections of humans and ixodid ticks in epidemic seasons 2014-2018 on the territories of natural foci of Primorsky Krai. Methods. Assessment of the activity and prevalence of pathogens of tick-borne infections was obtained by analyzing the following three parameters: infection of ticks collected from vegetation, sucked ticks removed from people, and blood samples of individuals 2-3 days after the tick bite. Results. Using a real-time PCR, we have shown the existence in the southeast of the Primorsky Krai of the six causative agents of tick-borne infections (TBE, Lyme disease, tick-borne recurrent fever caused by Borrelia miyamotoi, granulocyte anaplasmosis, mononuclear ehrlichiosis and tick-borne rickettsiosis). Most often in ixodid ticks detected borrelia (Borrelia burgdorferi s.l., and Borrelia miyamotoi). In single cases, genetic markers of TBE virus, anaplasm and erlichia have been identified. Besides, Rickettsia heilongjiangensis DNA was detected in these areas. The interrelation between infection of ixodid ticks with tick-borne pathogens and rates of morbidity in these infections in Primorsky Krai was established. Conclusions. The data obtained concentrate attention of researchers on a variety of existing tick-borne infections, which by now represent a new, urgent problem and require further careful study not only of "old" previously known pathogens but also new newly discovered and, perhaps, not yet discovered pathogens of tick-borne natural focal infections.