Intestinal parasites cause welfare harm to dogs and pose public health risks. Systematic prevention protects both dog welfare and human health in a One Health approach.
Intestinal parasite infection causes chronic welfare harm through protein malabsorption, anemia from hookworm blood feeding, and in heavy infections, failure to thrive. Puppies with severe roundworm or hookworm infections show pot-bellied appearance, poor coat quality, lethargy, and in heavy infections, death. The welfare burden falls disproportionately on rescue and shelter dogs and those in kennels where environmental contamination maintains high parasite pressure. The One Health dimension - intestinal parasites from dogs infecting children who play in contaminated soil - creates dual welfare and public health arguments for systematic parasite control programs.