title: Long-term study of the prevalence of Borrelia burgdorferi s.l. infection in ticks (Ixodes ricinus) feeding on blackbirds (Turdus merula) in NE Poland.
abstract: Seeking evidence to confirm that blackbirds (Turdus merula) may be involved in environmental maintenance of Borrelia burgdorferi s.l. (the causative agent of Lyme borreliosis), we conducted a long-term study over three separate 2-year periods, together embracing a span of almost 20 years, all in the same area in northeastern Poland. We examined a total of 78 blackbirds and collected 623 Ixodes ricinus ticks feeding on them. The tick infestation prevalence was found to be very high (89.7 %). Among all ticks collected, 9.8 % individuals were infected with B. burgdorferi s.l. spirochetes. We found statistically significant growth in the prevalence of infected ticks as well as an increasing proportion of blackbirds hosting them in subsequent years of study. Ticks feeding on blackbirds were infected mainly with B. garinii (45.7 %), a genospecies commonly encountered in birds, and with B. afzelii (28.6 %), until recently considered rodent-associated. We also identified B. turdi (22.9 %), frequently found in recent years in ticks feeding on birds, and B. spielmanii (2.8 %), which had previously not been found in infected ticks feeding on blackbirds. We also found that ticks infected with genospecies associated with avian reservoir groups (B. garinii and B. turdi) were not randomly distributed on blackbirds, but instead focused on certain bird specimens. We therefore conjecture that this is a result of ticks becoming infected either from the host blackbird itself, or from other infected ticks feeding on the same host blackbird. We did not find any similar dependency for the rodent specialist B. afzelii.
authors.affiliation: Department of Ecology, Institute of Zoology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, 101 Żwirki i Wigury St., 02-089, Warsaw, Poland. alicja@biol.uw.edu.pl.
authors.forename: Alicja
authors.initials: A
authors.lastname: Gryczyńska
authors.affiliation: Department of Parasitology, Institute of Zoology, Faculty of Biology, University of Warsaw, 1 Miecznikowa St., 02-096, Warsaw, Poland.
authors.forename: Renata
authors.initials: R
authors.lastname: Welc-Falęciak
mesh_terms: D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000469:parasitology; D015748:Borrelia burgdorferi Group / Q000302:isolation & purification / Q000502:physiology; D004197:Disease Reservoirs / Q000382:microbiology / Q000662:veterinary*; D005260:Female; D018884:Ixodes / Q000254:growth & development / Q000382:microbiology* / Q000502:physiology*; D007814:Larva / Q000254:growth & development / Q000382:microbiology / Q000502:physiology; D008193:Lyme Disease / Q000453:epidemiology* / Q000382:microbiology; D008297:Male; D009758:Nymph / Q000254:growth & development / Q000382:microbiology / Q000502:physiology; D011044:Poland / Q000453:epidemiology; D015995:Prevalence; D020308:Songbirds; D013984:Tick Infestations / Q000469:parasitology / Q000662:veterinary
keywords: Blackbirds; Borrelia burgdorferi s.l.; Ixodes ricinus; Lyme borreliosis