Whipworms have a direct life cycle meaning there are no intermediate hosts. They are also not transmitted to unborn puppies or via nursing. Whipworm eggs are passed from the dog to the soil in stool, just like the other worms previously discussed. In two to four weeks the eggs become infective and can be ingested by the dog during routine grooming as previously discussed. The eggs hatch in the small intestine, then the larvae proceed to the large intestine where it embeds in the tissue and continues to mature. Approximately 75 days after ingestion the whipworms will be producing eggs and the cycle begins again.
Although whipworms do suck blood it's typically not enough to be significant. The primary symptom of whipworm infection is diarrhea. Because whipworms are cyclic egg layers it's quite possible to have a negative fecal sample in spite of infection. For this reason treatment is often instituted if symptoms are present even with a negative fecal sample. Also because of this, even a single egg seen in a sample should be considered significant.
Whipworms are not susceptible to all dewormers. Panacur (fenbendazole), and Drontal Plus (febantel) will treat whipworms. Also some heartworm preventatives such as Interceptor and Sentinel (milbemycin) or Advantage multi (Moxidectin) will also treat whipworms. Because of the long life cycle of the whipworm a second deworming must be done 2-5 months after the first one, and often another one is recommended in between. An easy protocol to remember is to deworm at time of diagnosis, then again in 3 weeks, and in 3 months. Also because of the longer life cycle and lack of maternal transmisstion, whipworms are not seen in very young puppies.
Whipworm eggs are extremely hardy and can live in the environment for years. This is a big problem as dogs can continually reinfect themselves if they live in a contaminated environment. For these cases it is especially recommended to use one of the heartworm preventatives that cover whipworms.
Whipworms do not infect humans.