Sessions

The carcinogenic effects of passive smoking are well established, however, this field has been scarcely investigated in companion animals. Our study aimed to detect secondary and tertiary tobacco product exposure and to explore its potential association with neoplastic diseases in dogs and cats. As a biomarker, we measured cotinine, the main metabolite of nicotine, in serum and fur samples. Initially, cotinine was analyzed using ELISA-based assays, but these tests did not provide sufficient sensitivity for reliable detection of the low concentrations of the given samples. Therefore, we developed and compared LC-MS–based methods as part of a methodological optimization. Based on literature data, four extraction protocols were evaluated: three non-SPE and one SPE method. The SPE protocol displayed an 8–9-fold higher recovery efficiency compared to the alternatives and was therefore selected for routine application.

Using the optimized procedure, we conducted retrospective analyses of canine and feline samples submitted for pathological examination, quantifying cotinine levels and comparing them with tumor findings documented during necropsy. In our pilot study, serum and fur samples from 7 dogs and 3 cats were analyzed. In one animal, cotinine was undetectable in both matrices, in two cases, it was present only in serum, while in one case, only in fur. In six animals, cotinine was detectable in both serum and fur samples. A general trend was observed whereby higher serum cotinine concentrations were associated with higher fur cotinine levels.

Our findings confirmed the practical applicability of the method and validated it as a promising tool for the investigation of passive smoke exposure from pathological samples. This research enables biomarker-based verification of tobacco product exposure and provides the basis for evaluating potential correlations with specific tumor types. Furthermore, it may contribute to a better understanding of species-related susceptibility in companion animals and to mapping the veterinary health risks of passive smoking.