Cause
Transmission of whipworms occurs when a dog eats soil containing whipworm eggs that have matured to the infective stage, a process that takes about one month. The infective eggs are very hard to kill and are resistant to both heat and drying; they can survive in the dirt for a very long time -- from several months to years. Thus, even if the dog is treated for whipworms, re-infection is common if the environment is not kept clean and free of feces.