Contamination of wild boars' (Sus scrofa) muscles with tetracycline antibiotic from oral-delivered rabies vaccine baits.

Tetracycline (TC) is used as a biomarker for rabies vaccine bait intended for foxes. However, there is a high probability of intake of the vaccine by other species living in the forest ecosystem, including wild boars (Sus scrofa), and TC residues can occur in the animals' tissues. In this study, muscle samples from 144 animals were tested for the presence of TC, collected after rabies vaccine distribution. For the quantitative analysis of TC and its 4-epi form, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed. The results of this study show that TC was found in 53 samples, which represents 37% of all tested animals. The concentrations were in the range 5-286 µg/kg. The preliminary results suggest that the risk exists of contamination of muscle tissue of wild boars with TC from oral-delivery rabies vaccine baits containing the antibiotic. Control should be considered of TC residues in wild boar meat for human consumption.