Emerging Echinococcus tapeworms: fecal PCR detection of Echinococcus multilocularis in 26 dogs from the United States and Canada (2022-2024).

Abstract

Objective: To report quantitative PCR (qPCR) detection of Echinococcus multilocularis DNA in fecal samples from 26 dogs in the US and Canada.

Animals: 26 dogs with fecal samples submitted for parasite screening by qPCR.

Clinical presentation: Dog signalment, presenting concern, preventive care, and outcomes were obtained from the primary veterinarian via email or telephone, where available.

Results: Echinococcus multilocularis was detected in 26 of 2,333,797 dog fecal samples by reference laboratory fecal qPCR surveillance between March 2022 and July 2024. Seventeen E multilocularis-detected samples were sequenced as European haplotypes (E3/E4). Taenia-type eggs were identified by zinc sulfate centrifugal flotation in 8 of 17 samples (47%). Dogs were from the US (n = 16) and Canada (10). Ten dogs had gastrointestinal signs (diarrhea) reported on initial presentation. Clinical history revealed that some dogs were receiving a monthly antiparasitic preventive in the 6-month period prior to sampling (n = 10) and had regular wildlife (rodent) exposure (13). Twenty-five dogs were subsequently confirmed to have received treatment with praziquantel for detected E multilocularis, and 25 of these dogs were qPCR negative 3 to 5 weeks after treatment.

Clinical relevance: Veterinary awareness of endemic risk regions for E multilocularis and its emergence in novel areas (Colorado, Nevada, Wyoming, Montana, Illinois, Washington, Idaho, Kansas, and Oregon) are key for One Health. Dogs can serve as sentinels for Echinococcus tapeworm risk, and detection of E multilocularis tapeworms in dogs through routine qPCR fecal screening can alert clinicians to zoonotic concern and common environmental exposure risk.