Diagnosis, treatment, and outcome of four dogs with alveolar echinococcosis in the northwestern United States.

OBJECTIVE: To describe the clinical disease, diagnostic findings, medical management, and outcome in dogs with alveolar echinococcosis (AE).

ANIMALS: 4 dogs with naturally occurring AE.

PROCEDURES: Medical records were retrospectively reviewed from 2020 to 2022 to identify dogs diagnosed with AE. Signalment, case history, clinical signs, imaging and pathological laboratory findings, treatment, and clinical outcome were reported.

RESULTS: All dogs developed systemic clinical illness and weight loss. Abdominal ultrasonography revealed multifocal to coalescent cystic masses of variable size distributed throughout the liver in all cases. Evaluation of aspirated hepatic cyst contents included membranous parasite structures and calcareous corpuscles. Echinococcus multilocularis was confirmed via PCR from hepatic cyst fluid in 3 of 4 cases. Treatment included systemic benzimidazole and praziquantel administration, 1 or more instances of ultrasound-guided cyst drainage in all cases, with ethanol ablation (percutaneous aspiration-injection-reaspiration) in 2 cases, and surgical resection in 1 case. Two of 4 dogs were euthanized within 5 months of diagnosis. One of these dogs was necropsied and had nearly complete obliteration of the hepatic parenchyma by multilocular cystic masses. One dog is still alive, and 1 dog has been lost to follow-up.

CLINICAL RELEVANCE: This series of cases highlighted the diagnostic findings and therapeutic intervention in 4 dogs with AE. This was the first report of medical management incorporating the percutaneous aspiration-injection-reaspiration method used in humans. Reports of canine AE are rare in the US, so this series serves to help raise awareness of hepatic AE in the northwestern US.