Borrelia burgdorferi sensu lato in Ixodes ricinus ticks collected from migratory birds in Southern Norway.
BACKGROUND
Borrelia burgdorferi sensu lato (s.l.) are the causative agent for Lyme borreliosis (LB), the most common tick-borne disease in the northern hemisphere. Birds are considered important in the global dispersal of ticks and tick-borne pathogens through their migration. The present study is the first description of B. burgdorferi prevalence and genotypes in Ixodes ricinus ticks feeding on birds during spring and autumn migration in Norway.


METHODS
6538 migratory birds were captured and examined for ticks at Lista Bird Observatory during the spring and the autumn migration in 2008. 822 immature I. ricinus ticks were collected from 215 infested birds. Ticks were investigated for infection with B. burgdorferi s.l. by real-time PCR amplification of the 16S rRNA gene, and B. burgdorferi s.l. were thereafter genotyped by melting curve analysis after real-time PCR amplification of the hbb gene, or by direct sequencing of the PCR amplicon generated from the rrs (16S)-rrl (23S) intergenetic spacer.


RESULTS
B. burgdorferi s.l. were detected in 4.4% of the ticks. The most prevalent B. burgdorferi genospecies identified were B. garinii (77.8%), followed by B.valaisiana (11.1%), B. afzelii (8.3%) and B. burgdorferi sensu stricto (2.8%).


CONCLUSIONS
Infection rate in ticks and genospecies composition were similar in spring and autumn migration, however, the prevalence of ticks on birds was higher during spring migration. The study supports the notion that birds are important in the dispersal of ticks, and that they may be partly responsible for the heterogeneous distribution of B. burgdorferi s.l. in Europe.
University of Agder, Kristiansand, Norway. vivian.kjelland@uia.no
Vivian
V
Kjelland
Snorre
S
Stuen
Tone
T
Skarpaas
Audun
A
Slettan
D025041:Animal Migration; D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology / Q000469:parasitology*; D001717:Birds; D025065:Borrelia burgdorferi / Q000235:genetics / Q000302:isolation & purification*; D016009:Chi-Square Distribution; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D018884:Ixodes / Q000382:microbiology*; D008193:Lyme Disease / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D009664:Norway / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000662:veterinary; D015995:Prevalence; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics; D012621:Seasons; D017282:Tick-Borne Diseases / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S