Several types of tapeworms—properly known as cestodes—may infect dogs. Adult tapeworms are segmented worms found in the intestines of dogs. They rarely cause serious disease.
Most urban dogs eat prepared foods and have restricted access to natural prey. These dogs may acquire Dipylidium caninum (the common tapeworm of dogs and cats) from eating fleas.
Suburban, rural, and hunting dogs have more access to various small mammals, in addition to raw meat and offal from large mammals. The possibility of exposure to a number of different tapeworm species can be expected in such dogs and typically are Taenia species or Echinococcus granulosus. Other species of tapeworms that may infect dogs include Spirometra mansonoides and Diphyllobothrium and Mesocestoides species.
Signs of infection vary from a failure to digest and absorb food normally, malaise, irritability, variable appetite, and shaggy coat to colic and mild diarrhea. There may be no signs in mild cases. In rare cases, telescoping of the intestine (intussusception), emaciation, and seizures are seen. Diagnosis is based on finding tapeworm segments or eggs in the feces or stuck to the hair around the anus.
Control of tapeworms requires both treatment and prevention. Even confined dogs can contract Dipylidium caninum because it can cycle through fleas. Thus, flea control is the critical preventive step even for indoor dogs. Animals that roam freely usually become reinfected by eating dead or prey animals. Preventing such feeding will limit exposure to other tapeworm species.
An accurate diagnosis will enable the veterinarian to provide effective advice on treating the infection and preventing reinfection.