Risk factors for Echinococcus multilocularis intestinal infections in owned domestic dogs in a North American metropolis (Calgary, Alberta).

Human alveolar echinococcosis is increasingly documented in Alberta, Canada. Its causative agent, Echinococcus multilocularis (Em), can be transmitted to humans by infected dogs. We assessed the prevalence and associated risk factors for Em infections in domestic dogs in Calgary, Alberta, Canada. In this cross-sectional study that coupled collection and assessment of dog feces with a survey on potential risk factors, 13 of 696 (Bayesian true prevalence, 2.4%; 95% CrI: 1.3-4.0%) individual dogs' feces collected during August and September 2012 were qPCR positive for Em. Sequencing two of these cases indicated that both were from the same Em European strain responsible for human infections in Alberta. Likelihood of intestinal Em was 5.6-times higher in hounds than other breeds, 4.6-times higher in dogs leashed at dog parks than those allowed off-leash, 3.1-times higher in dogs often kept in the backyard during spring and summer months than those rarely in the yard, and 3.3-times higher in dogs living in neighbourhoods bordering Bowmont park than those in other areas of Calgary. This situation warrants surveillance of dog infections as a preventative measure to reduce infections in North America.

Assessing the potential for infections of Echinococcus multilocularis in dogs in a hotspot of human alveolar echinococcosis infections in North America.

Echinococcus multilocularis is a zoonotic tapeworm, whose metacestode larval stage is the etiological agent for alveolar echinococcosis in humans and is a parasite of emerging concern according to the World Health Organization which is difficult to diagnose and has a case mortality rate of >90% when left untreated. Echinococcus multilocularis requires two mammalian hosts to complete its lifecycle: wild and domestic canids as definitive hosts, and small mammals (mostly rodents) as intermediate ones. Because of their close relations with humans, domestic dogs have been indicated as a mean of infection to people. Human alveolar echinococcosis has historically been rare in North America, however, since 2013, at least seventeen diagnoses have been confirmed in Alberta, Canada. Because of this unprecedented series of cases, assessing the frequency of infections in dogs in Alberta is key to estimate risk for dog owners and animal health professionals. This study was carried out in Edmonton to determine the frequency of E. multilocularis infection in domestic dogs and potential risk factors. Fecal samples and corresponding behavior risk surveys were collected from 775 dogs in seven urban off-leash parks within Edmonton city limits during the summer of 2020. A quantitative PCR fecal test was used to diagnose E. multilocularis infection. We found a single case of E. multilocularis infection (1/775) and determined that the overall true prevalence was 0.2% (95% CrI: 0.0-0.7%) corrected for detection sensitivity and specificity. Overall, these findings confirm the presence of E. multilocularis infection in domestic dogs in Edmonton although further work is required to fully understand the risk factors that may contribute to infection and potential transmission to humans.

A global assessment of Echinococcus multilocularis infections in domestic dogs: proposing a framework to overcome past methodological heterogeneity.

Echinococcus multilocularis, the aetiological agent of human Alveolar Echinococcosis, is transmitted between small mammals and wild or domestic canids. Dogs infected with E. multilocularis as dead-end hosts. Whereas E. multilocularis infections in wild hosts and humans have been well-studied in recent decades, infections in domestic dogs are sparsely reported. This literature review and meta-analysis highlighted gaps in the available data and provided a re-assessment of the global distribution of domestic dog E. multilocularis infections. We found 46 published articles documenting the prevalence of E. multilocularis in domestic dogs from 21 countries across Europe, Asia and North America. Apparent prevalence estimates ranged from 0.00% (0.00-0.33%) in Germany to 55.50% (26.67-81.12%) in China. Most studies were conducted in areas of high human Alveolar Echinococcosis. By accounting for reassessed diagnostic sensitivity and specificity, we estimated true prevalence in a subset of studies, which varied between 0.00% (0.00-12.42%) and 41.09% (21.12-65.81%), as these true prevalence estimates were seldom reported in the articles themselves. Articles also showed a heavy emphasis on rural dogs, dismissing urban ones, which is concerning due to the role urbanisation plays in the transmission of zoonotic diseases, especially those utilising pets as definitive hosts. Lastly, population studies on canine Alveolar Echinococcosis were absent, highlighting the relative focus on human rather than animal health. We thus developed a framework for investigating domestic dog E. multilocularis infections and performing risk assessment of dog-associated transmission to fill the gaps found in the literature.