DVM Student Colorado State University Fort Collins, Colorado, United States
Abstract: Background. Echinococcus multilocularis is a zoonotic tapeworm with re-emerging public health significance. Wild canids are the natural definitive hosts, experience subclinical infection from adult worms, and pass eggs in their feces. Intermediate hosts like rodents ingest the eggs, and the larvae migrate from the intestines predominantly to the liver, where multiple cysts develop. Rarely, domestic dogs and people serve as aberrant hosts and develop life-threatening multiple hepatic cysts (alveolar echinococcosis). Objectives. To describe the clinical findings associated with E. multilocularis in client-owned dogs on the front range of Colorado. Animals. Three domestic dogs living in Boulder County, Colorado in 2023 and 2024. Methods. Echinococcus multilocularis DNA was amplified by a commercially available PCR (KeyScreen; Antech Diagnostics). The medical records from positive dogs were reviewed and discussed with the respective clinicians. Results. Two dogs with mild diarrhea were positive (confirmed) for E. multilocularis DNA in feces once. These dogs were negative one week after praziquantel administration and there was no evidence of systemic illness. The third dog has multiple hepatic masses/cysts that have been present for over a year; fine-needle aspirates of the liver confirmed the presence of E. multilocularis DNA. This dog was negative for the parasite in feces, alveolar echinococcosis was diagnosed, and the dog is under long-term fenbendazole treatment. To our knowledge, no human family members have been infected. Conclusions and Clinical Importance. The zoonotic nature of this parasite’s life cycle and frequent contact between humans and domestic dogs highlight the public health relevance of these findings.
