Coexistence of emerging bacterial pathogens in ixodes ricinus ticks in Serbia

Abstract

The list of tick-borne pathogens is long, varied and includes viruses, bacteria, protozoa and nematodes. As all of these agents can exist in ticks, their co-infections hove been previously reported. We studied co-infections of emerging bacterial pathogens (Borrelia burgdorferi sensu lato, Ana plasma phagocytophilum and Francisella tularensis) in Ixodes ricinus ticks in Serbia. Using PCR technique, we detected species-specific sequences, rrf-rrl rDNA intergenic spacer for B. burgdorferi s.l., p44/msp2 paralogs for A. phagocytophilum, and the 17 kDa lipoprotein gene, TUL4, for F tularensis, respectively, in total DNA extracted from the ticks. Common infections with more than one pathogen were detected in 42 (28.8 %) of 146 infected l. ricinus ticks. Co-infections with two pathogens were present in 39 (26.7 %) of infected ticks. Simultaneous presence of A. phagocytophilum and different genospecies of B. burgdorferi s.l. complex was recorded in 16 ticks, co-infection with different B. burgdorferi s. l. genospecies was found in 15 ticks and eight ticks harbored mixed infections with F tularensis and B. burgdorferi s.l. genospecies. Less common were triple pathogen species infections, detected in three ticks, one infected with A. phagocytophilum / B. burgdorferi s.s. / B. lusitaniae and two infected with F tularensis / B. burgdorferi s.s. / B. lusitaniae. No mixed infections of A. phagocytophilum and F. tularensis were detected.