Echinococcus multilocularis: Difference between revisions
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Echinococcus multilocularis
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* Intermediate hosts (metacestode) are rodents, possibly pigs, and and incidentally humans |
* Intermediate hosts (metacestode) are rodents, possibly pigs, and and incidentally humans |
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* Intermediate host is eaten by the definitive host, completing the life cycle |
* Intermediate host is eaten by the definitive host, completing the life cycle |
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+ | === Epidemiology === |
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+ | * Estimated 18,000 cases annually |
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+ | * Worldwide in the northern hemisphere |
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+ | ** Most cases in China (90%), followed by Japan and Russia |
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+ | ** Rare in North America |
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+ | * Within Canada: |
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+ | ** Alberta has highest number of cases, with 19 cases from 2013 to 2021 |
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+ | ** 0 to 3 case reports in other provinces |
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==Clinical Manifestations== |
==Clinical Manifestations== |
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* Combination of radiologic and serologic investigations |
* Combination of radiologic and serologic investigations |
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+ | *A single negative serologic test does not rule out infection |
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* May be confirmed by biopsy |
* May be confirmed by biopsy |
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Revision as of 16:45, 23 November 2021
Background
Microbiology
- Cestode in the Echinococcus family
- Disease is caused by the larval form
Life Cycle
- Definitive hosts are canid carnivorous animals
- Eggs contaminate the environment, including produce
- They are infective after a few days, and are viable for up to 16 months at 4ºC
- Intermediate hosts (metacestode) are rodents, possibly pigs, and and incidentally humans
- Intermediate host is eaten by the definitive host, completing the life cycle
Epidemiology
- Estimated 18,000 cases annually
- Worldwide in the northern hemisphere
- Most cases in China (90%), followed by Japan and Russia
- Rare in North America
- Within Canada:
- Alberta has highest number of cases, with 19 cases from 2013 to 2021
- 0 to 3 case reports in other provinces
Clinical Manifestations
- Causes alveolar echinococcosis
- Incubation period 5 to 15 years
- Vague abdominal pain may precede diagnosis by years
- Presents as a metastatic malignancy of unknown primary, mot commonly with malaise, weight loss, and right upper quadrant discomfort
- May also mimic hepatocellular carcinoma, cirrhosis, and tuberculosis
- Causes continuously-growing tumour-like polycystic mass, made up of multiple vesicles that are lined by laminated germinal layer
- Can cause cholestatic jaundrice, cholangitis, portal hypertension, and Budd-Chiari syndrome
Diagnosis
- Combination of radiologic and serologic investigations
- A single negative serologic test does not rule out infection
- May be confirmed by biopsy
Management
- Main treatment is surgical resection followed by at least 2 years of antihelminthic therapy (e.g. albendazole)
- Poor prognosis, with 90% 10-year mortality if untreated