Lyme borreliosis, an infection caused by the tick-borne spirochete Borrelia burgdorferi, is a major health problem for populations in areas of endemicity in the Northern Hemisphere.
In the present study we assessed the density of ticks and the prevalence of B. burgdorferi sensu lato among ticks in popular urban recreational areas of Helsinki, Finland.
Altogether 1,688 Ixodes ricinus ticks were collected from five areas located within 5 km of the downtown section of Helsinki, and 726 of them (303 nymphs, 189 females, and 234 males) were randomly chosen for laboratory analysis.
The midguts of the ticks were divided into three pieces, one for dark-field microscopy, one for cultivation in BSK-II medium, and one for PCR analysis.
Ticks were found in all the study areas ; their densities varied from 1 to 36 per 100 m along which a cloth was dragged.
The rate of tick infection with B. burgdorferi sensu lato varied from 19 to 55%, with the average being 32%. Borellia afzelii was the most predominant genospecies in all the areas, and no B. burgdorferi sensu stricto isolates were detected.
Only two ticks were concurrently infected with both B. afzelii and Borrelia garinii.
Dark-field microscopy gave more positive results for B. burgdorferi than did cultivation or PCR analysis.
However, the agreement between all three methods was fairly good.
We conclude that Lyme borreliosis can be contracted even in urban environments not populated with large mammals like deer or elk. (...)
Mots-clés Pascal : Borrelia burgdorferi, Spirochaetaceae, Spirochaetales, Bactérie, Ixodes ricinus, Ixodidae, Ixodida, Parasitiformes, Acari, Arachnida, Arthropoda, Invertebrata, Vecteur, Surveillance sanitaire, Epidémiologie, Prévalence, Milieu urbain, Variation géographique, Détection, Evaluation performance, Finlande, Europe, Pays Scandinaves
Mots-clés Pascal anglais : Borrelia burgdorferi, Spirochaetaceae, Spirochaetales, Bacteria, Ixodes ricinus, Ixodidae, Ixodida, Parasitiformes, Acari, Arachnida, Arthropoda, Invertebrata, Vector, Sanitary surveillance, Epidemiology, Prevalence, Urban environment, Geographical variation, Detection, Performance evaluation, Finland, Europe, Scandinavia
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0251417
Code Inist : 002A05B11. Création : 16/11/1999.