The occurrence of spotted fever rickettsioses and other tick-borne infections in forest workers in Poland.

The presence of antibodies to Rickettsia conorii, R. helvetica, R. felis, R. slovaca, R. sibirica, and R. massiliae in sera of 129 forest workers from northeastern and southern Poland was assayed by indirect immunofluorescence. Previous environmental studies revealed presence of spotted fever group (SFG) rickettsiae in ticks collected from these areas. Additionally, the workers were examinated for the presence of antibodies specific to other tick-borne bacteria: Anaplasma phagocytophilum, Bartonella spp., and B. burgdorferi. The results of the studies have shown the presence of specific SFG rickettsiae antibodies in 14.7% of tested forest workers, among them 78.9% had species-specific antibodies to R. massiliae. Contrary to previous detection R. helvetica and R. slovaca in ticks collected in the environment of the examined area, no species-specific antibodies to these species were detected in studied workers. Antibodies to B. burgdorferi (44%) were found in forest workers more often than antibodies to other tested pathogens. B. burgdorferi was also the main component of coinfections. The most frequent confirmed serologically coinfections were simultaneous infections with B. burgdorferi and Bartonella spp. found in 10% of tested individuals. So far, SFG rickettsiae infections have not been diagnosed in Poland; however, the presence of the bacteria in ticks and presence of specific antibodies in humans exposed to arthropods show the need for monitoring the situation. The list of tick-borne pathogens is increasing, but knowledge about the possibility of humans acquiring multipathogens infections after tick bite still needs evaluation.