Comparative Analysis of Bacterial Tick-Borne Pathogens in Questing Ticks from Sambia Peninsula, Kaliningrad Oblast, Russia: Spring and Autumn Prevalence and Public Health Risks

The Kaliningrad Oblast, located in the westernmost part of Russia and bordering European Union countries, is a popular tourist destination. However, limited research has been conducted on the bacteria found in ticks in this region. We, therefore, investigated the prevalence of certain bacteria, including <i>Borrelia</i>, <i>Rickettsia</i>, <i>Anaplasma</i>, and <i>Ehrlichia</i>, as well as the genospecies of the spotted fever group <i>Rickettsia</i> (SFGR) in <i>Ixodes ricinus</i> and <i>Dermacentor reticulatus</i> tick species. To accomplish this, we employed commercial qPCR for pathogen screening. We identified specific genospecies by sequencing the <i>gltA</i> and <i>ompA</i> gene fragments. In <i>I. ricinus</i> ticks, we found <i>Borrelia burgdorferi</i> sensu lato DNA in 35.6% of samples. We also found <i>Rickettsia helvetica</i> in 17.5% of ticks. Additionally, we detected <i>Borrelia miyamotoi</i> in 1.7% and <i>Anaplasma phagocytophilum</i> in 2.6%, while <i>Ehrlichia chaffeensis</i>/<i>Ehrlichia muris</i> were present in 0.6%. In <i>D. reticulatus</i> ticks, we detected only <i>Rickettsia conorii</i> subsp. <i>raoultii</i> DNA, with a prevalence of 6.1%. These findings demonstrate a substantial risk of Lyme disease and other tick-borne infections from early spring through late autumn, emphasizing the importance of ongoing monitoring for these pathogens in the region.