Prevalence of pulmonary anthracosis in household dogs in southwest states in Nigeria: a sentinel for environmental pollution.

Nigeria, stemming from vehicular traffic, generator sets, industrial sources, residential combustion, and road dust. Pulmonary anthracosis, the accumulation of carbon particles in the lungs, is a known risk factor for cancer. While this condition has been observed in stray dogs, data on its prevalence in household dogs is limited. This study aimed to determine the prevalence of pulmonary anthracosis in household dogs within three southwestern states of Nigeria over a decade (2011-2020) and to analyze the histopathological features of pulmonary anthracosis observed in canine lung tissue samples submitted for post-mortem examination. Lung tissue samples from 472 dog carcasses submitted to the Federal University of Agriculture, Abeokuta, and the University of Ibadan for post-mortem examination were analyzed in this study. Lesions suggestive of pulmonary anthracosis were identified through gross examination and further analyzed histologically to confirm their characteristics. The findings were presented using tables, charts, and chi-square to determine association between breed, age, and sex considering p < 0.05 as significant. Out of total lungs sampled, 150 (31.8%) were positive for pulmonary anthracosis. No significant association was found between breed (p = 0.95) or sex (p = 0.98) and anthracosis, but age was statistically significant (p = 0.01). Histopathological findings included bronchiolar smooth muscle hypertrophy (90%), severe fibrosis (80%), and bronchiolar epithelial hyperplasia (50%). The study concluded that pulmonary anthracosis is prevalent among household dogs in the region. The pathological changes highlighted the adverse effects associated with the condition in affected organs and that black carbon as a major air pollutant that poses health risks to humans and animals.