Echinococcosis in dogs in Alberta

Alveolar echinococcosis (AE) is caused by infection with the larval stages of the tapeworm, Echinococcus multilocularis (Em) following ingestion of eggs from the environment. AE results in formation of vesciculated tumor-like lesions within the livers of intermediate hosts, primarily rodents. Occasionally, AE can occur in humans and also in dogs, although usually definitive hosts (wild and domestic canids) are not receptive to infection via egg ingestion. Normally, in definitive hosts adult parasites typically develop in the small intestine and release eggs that will be shed into the environment through feces.Although rare, when it occurs, AE in dogs is a severe condition frequently culminating in liver failure and euthanasia.

Despite recent reporting of several cases of canine AE in Canada, no epidemiological study has been conducted to assess the true incidence of this infection in North America, and there are no clear clinical guidelines for diagnosis, treatment or prevention of this disease. Veterinarians often struggle to diagnose AE in dogs, due to a lack of understanding of this disease, and due to its perceived rarity, it is often not included on their list of differential diagnoses. Diagnosis usually is considered only when clear liver involvement is detected by medical imaging and subsequent histological and molecular examination of liver biopsies reveal AE. Although, shedding of eggs in feces can be detected through floatation techniques in canids acting as definitive hosts, this is not a diagnostic test for AE. Often by the time a diagnosis of AE is made the disease is too advanced to treat and mortality is high.

With our project we aim to 1) establish the seroprevalence (force of infection) of Em in client-owned dogs; 2) estimate the incidence of enteric versus alveolar echinococcosis in client owned dogs in Alberta; 3) assess risk factors for infection; 4) provide veterinarians with a protocol for early diagnosis and treatment of AE; 5) develop information packages to inform owners and animal healthcare professionals about AE in order to minimize the risk of human and dog exposure and infection. By filling the current knowledge gaps in our understanding of the epidemiology, diagnosis and treatment of AE in Albertan dogs, it is our aim to reduce the risk of disease transmission to owners, their pets, and animal healthcare professionals. We will use the information gained to create recommendations for the prevention, diagnosis and treatment of canine AE, and work with Alberta Health Services to develop guidelines for minimizing zoonotic transmission.