Essentials of Diagnosis
- Motile proglottids 23 by 8 mm.
- Proglottids have genital pores at either end and contain egg clusters.
- Eggs occur in compartmented clusters (diagnostic).
- Scolex has 4-7 rows of hooklets and 4 suckers.
General Considerations
D caninum is distributed worldwide and is associated with wild and domesticated cats and dogs. The life cycle is similar to that of H diminuta, with an obligatory arthropod intermediate host. The adult worm lives in dogs, cats, or humans, and gravid proglottids are released from the adult worm either singly or in short chains. Eggs are passed in the stool, and ingestion of eggs by the intermediate host results in the development of the larval form within the arthropod host. Ingestion of the arthropod that contains larvae results in the development of an adult worm in dogs, cats, or humans. Adult worms may reach 10-80 cm in length.
Clinical Findings
Signs and Symptoms
Infection with D caninum is not commonly associated with clinical symptoms, although indigestion or anorexia may be present. Also anal pruritus has been reported.
Laboratory Findings
Microscopic stool examination will frequently reveal characteristic egg clusters and proglottids. As with other cestode infections, blood examination may demonstrate mild leukocytosis with eosinophilia.
Differential Diagnosis
Since D caninum infection in humans is often asymptomatic, most patients do not seek medical care. Once eggs are found in the stool, the appearance of egg clusters is so characteristic that no other parasite could be confused with D caninum. When a patient does seek the care of a physician for indigestion or anorexia, a variety of gastric pathologies need to be ruled out (eg, peptic ulcer disease and gastric outlet obstruction).
Complications
No complications are associated with D caninum infection.
Treatment
Therapy for D caninum infection is niclosamide in a one-time dose (see Box 87-2).
Prognosis
The prognosis for D caninum infections is excellent.
Prevention & Control
Infection with D caninum can be reduced by screening domestic dog and cat stools and treating pets found to be infected (Box 3).