Untersuchungen zum Zeckenbefall und zur Prävalenz von Borrelia burgdorferi sowie Babesia divergens beim Rind im bayerischen Voralpenland

During the year 2002 319 cattle from 31 farms (6 districts) of
southern Bavaria were investigated for the presence of ticks during
the grazing period and 287 serum samples were tested for the
presence of antibodies against Borrelia burgdorferi and Babesia
divergens. Ticks were detected in all 31 farms and the mean
prevalence was 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 the infestation of the 221 positive
animals was generally low. 76,5 % of parasitized individuals had
1-6 ticks/cattle and day of investigation. By contrast, individuals
on pastures with appropriate tick-habitats showed up to 250
ticks/cattle and day of investigation. The percentage of infested
animals in each herd varied within the period between 0 100 %. The
investigation of 287 serum samples for the presence of antibodies
against Borrelia burgdorferi by immunfluorescence techniques
(IFAT), revealed antibody-titers ≥ 1:64 for 45,6 % of the animals.
27 of 31 farms showed prevalences of Borrelia burgdorferi ranging
from 20 to 100 %. There were no significant differences of positive
cattle between the various areas. However, a significant
correlation could be detected between the number of ticks per
cattle and the antibody concentration of anti-Borrelia IgG. By
contrast, there was no significant correlation between the age of
the animals and the serum antibody-titers. For comparative reasons,
64 IFAT-positive serum samples were tested by Westernblot
techniques for the presence of antibodies cross-reacting with
Borrelia garinii antigens. These analyses revealed that 69 % of the
samples reacted positively, 28 % were unclear and 3 % were
negative. The investigation of the 287 cattle sera for Babesia
divergens by means of IFAT revealed one positive animal with an
antibody-titer of 1:16. Finally, in an additional enzyme linked
immunosorbent assay (ELISA) 105 serum samples from 18 farms and 13
pooled sera including 45 cattle from the other 13 farms were tested
for the presence of antibodies against Fasciola hepatica. In 96,8 %
of the farms antibodies against Fasciola hepatica could be
detected.