[Tick infestation and the prevalence of Borrelia burgdorferi and Babesia divergens in cattle in Bavaria]

Abstract

During the grazing period 2002 319 cattle from 31 farms located in 6 districts of southern Bavaria were examined for the presence of ticks in 4- to 5-week intervals, and 287 serum samples were tested for the presence of antibodies against Borrelia burgdorferi and Babesia divergens. Ticks were detected in all 31 farms with a mean prevalence of 69%. 3218 out of 3453 collected ticks were Ixodes ricinus; 139 nymphs, 19 larvae and 77 damaged adult specimens could only be determined to the Genus level (Ixodes). The seasonal pattern revealed the highest frequencies of ticks in May/June and September. The intensity of tick infestation of positive animals was generally low. 76.5% of parasitized cattle had 1-6 ticks per day of investigation. Individual cattle showed up to 250 ticks per day. The percentage of infested animals in each herd varied within the period between 0-100%. The examination of serum samples by immunofluorescence technique (IFAT) revealed positive anti-Borrelia antibody titers (> or = 1:64) for 45.6% of the animals. The within-farm seroprevalence of borreliosis ranged from 20 to 100% in 27 of the 31 farms. A significant correlation could be detected between the number of ticks/cattle and the anti-Borrelia burgdorferi IgG-titer. By contrast, there was no significant correlation between the age of the animals and anti-Borrelia serum titers. For comparative reasons, 64 IFAT-positive serum samples were tested by Western blot techniques for the presence of antibodies cross-reacting with Borrelia garinii antigen. These analyses revealed that 69% of the samples reacted positively, 28% were unclear and 3% were negative. Examinations of the 287 serum samples for the presence of anti-Babesia divergens antibodies revealed one positive animal with a titer of 1:16.