A number of reports in recent years have shown that Borrelia burgdorferi can infect domestic animals, including cattle. The effects of this pathogen vary greatly among vertebrate species it infects, and the impact of B. burgdorferi on cattle is poorly understood. The aim of this ongoing study is to determine the symptoms and effects of “natural” infection (via tick bite) of B. burgdorferi on dairy cattle in a controlled situation. Field collected adult Ixodes scapularis were either 1) released directly on calves, 2) released in a small pasture with calves, or 3) not allowed access to calves (control calves). To date, 44% of the fully fed female ticks tested PCR positive for B. burgdorferi with 16S rDNA primers, indicating exposure to Lyme disease. Whole blood collected from the tick-fed animals tested negative with the same primers, but 33% of the skin biopsies taken near areas of tick attachment tested PCR positive for the spirochete. ELISA tests for serum antibodies to B. burgdorferi show a steady increase in titers for tick-fed calves, and have remained significantly higher than controls. No outward signs of disease including elevated temperature, swelling of major joints, weight loss, or rash, were observed for any animals during the acute phase of this study. Tissues and fluids taken from an infected calf during necropsy at week 15 are being tested for the presence of B. burgdorferi. The remaining calves will be continuously monitored for signs of chronic disease for the duration of the study.
Species 1: Acari Ixodidae Ixodes scapularis (blacklegged tick)
Species 2: Spirochaetales Spirochaetaceae Borrelia burgdorferi
Keywords: Lyme disease, cattle
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