Classification
Taxonomy
- Class: Cestodae.
- Family: Taeniidae.
- Genus: Echinococcus.
Distribution
World
- Northern hemisphere. Northern, central and eastern Europe, northern Asia and China, northern and south central Canada, north central USA.
- Found from western Alaska through northern Canada.
- In Alaska, the major threat is spill over into domestic dog populations from enzootic fox population.
- Also in large enzootic focus in central North America, including 13 north-central states in US and 3 provinces in Canada.
- Found in contiguous US as far south as Missouri and Indiana.
- Dogs and cats can become infected; in highly enzootic areas, 1-5% of farm cats may become infected (reported in Saskatchewan and North Dakota).
- Infection is common in dogs in some areas of Asia and North America, ie Alsaka and parts of China.
Europe
- Infection is currrently absent from Britain.
- There is mandatory praziquantel treatment of dgos and cats prior to entry into the Uk to prevent its introduction.
- Infection occurs in Germany, Switzerland, Austria, Belgium and France and is spreading. Infection is recorded in >60% of red foxes and spills over periodically into dogs and rarely cats.
- Normally 0.5-1% of rodents are infected.
Significance
In dog
- Asymptomatic.
- Must reduce activity and increase predation.
- Zoonosis. Human hazard group 3 pathogen.
- Trappers/hunters acquire infection from the sticky eggs on pelts.
- Farmers are another population at risk. They are infected by ingestion of eggs from fox/dog feces in soil, on vegetables/fruit, and on other food contaminated directly by feces.
- The alveolar cyst is invasive, 'tumor-like' in the liver and metastasizes to other organs, necessitating radical resection of the liver or liver transplant and prolonged, relatively toxic anthelmintic treatment.
- Infection does not always result in cyst developing but when it does death is almost inevitable unless treatment is instigated.
- Following infection, life expectancy is slightly reduced compared to normal life expectancy for males and females.
Sources
Publications
- Recent references from PubMed.
- Eckert J & Deplazes P (2004) Biological, epidemiological, and clinical aspects of echinococcosis, a zoonosis of increasing concern. Clinical Microbiology Reviews 17 , 107-135.
- Roberts M G & Aubert M F A (1995) A model for the control of Echinococcus multilocularis in France. Vet Parasitol 56 , 67-74 (Mathematical model of control in foxes).
