Whipworms are an intestinal parasite that affects dogs and humans. Transmission occurs when a dog or human ingests whipworm eggs shed through infected feces. These eggs enter the environment and can live in soil for months to years. While acquiring parasites from a dog is possible, whipworms are species specific and unable to spread from dogs to humans, so a lick from an infected dog will not spread the parasite to you.
The specific whipworm capable of infecting dogs is Trichuris vulpis. After ingestion, larvae develop in the small intestine before traveling to the cecum. Minor infestations often cause no symptoms. In more severe infestations, diarrhea, blood in the stool and weight loss.
Whipworms that infect humans are Trichuris trichiura. They mature in the small intestine and pass eggs through the stool. Like canine whipworms, the eggs can survive for months or years in the soil. Cases of human whipworms are common in areas where hygiene and sanitation are poor. Vegetables or fruits grown in areas exposed to human feces are often the mode of ingestion. Symptoms of human whipworm infection include stool with mucus or blood and pain when passing stool. In children, whipworm infestation leads to growth retardation and impaired cognitive development.