Foodborne parasitic infections CYSTIC and ALVEOLAR ECHINOCOCCOSIS

Human echinococcosis is are E. granulosus causing cystic The genotype causing the majority of a zoonotic disease caused echinococcosis [CE] (hydatidosis) CE in humans is E. granulosus, often ? by parasites of the genus and E. multilocularis causing maintained in a dog–sheep–dog Introduction Echinococcus. alveolar echinococcosis [AE]. cycle. Of the several species worldwide, Not all genotypes of E. granulosus the two most important in humans cause infections in humans.

Various mammals such as sheep, goats Dogs and wild carnivores act as the definitive Humans become infected through and camels act as intermediate hosts for host (in which the adult worm lives). They the ingestion of soil, water or CE (in which the larval stages of the worm become infected when they consume food (e.g. green vegetables, berries) develop), and rodents for AE. They become the organs of infected intermediate contaminated with the parasites’ eggs Transmission infected when they ingest tapeworm hosts that contain larval cysts. In dogs shed in the faeces of the carnivores, and and risk eggs in contaminated soil, food or and other carnivores, the larvae develop into also by hand-to-mouth transfer of eggs and the parasite develops into larval adult tapeworms. They shed tapeworm eggs after contact with the contaminated fur of factors water stages in their organs. in their faeces and contaminate soil, food a carnivore, most commonly a dog. and water.

Lack of personal Eating Eating Accidental host Definitive host hygiene organs of Lack of organs of (larval stages) (adult tapeworm) infected personal Accidental host infected animals Definitive host animals (adult tapeworm) hygiene (larval stages) E. granulosus Cystic echinococcosis E. multilocularis Alveolar Intermediate host Environment echinococcosis (larval stages) contaminated with infected dog faeces Environment Intermediate host contaminated with (larval stages) infected animal faeces

Hydatid disease Multilocular cysts

Cystic echinococcosis (hydatidosis): Human Both AE and CE are expensive and complicated to infection leads to development of one or more treat. Three options for the treatment cycle of CE hydatid cysts, most commonly in the liver and/or are: (i) percutaneous treatment of hydatid cysts lungs. The asymptomatic incubation period of the with the PAIR technique, (ii) surgery, (iii) anti- Signs and disease can last many years until the cysts grow Treatment infective drug treatment and (iv) “watch and wait” symptoms large enough to trigger clinical signs. (active monitoring). Clinical signs of cysts in the liver include abdominal Treatment of AE includes radical surgery, followed pain, nausea, and vomiting. Clinical signs of cysts by treatment with albendazole or no surgery and in the lungs include chronic cough, chest pain and lifetime treatment with albendazole. shortness of breath. Dogs can be treated with praziquantel. Alveolar echinococcosis: An asymptomatic incubation period can last 5–15 years, with slow, progressive, development of a primary tumor-like 1. Prevention and control of CE in animals lesion in the liver. Clinical signs include weight loss, • Avoid feeding dogs with offal; safe disposal of abdominal pain, general malaise and hepatic failure. infected offal Metastases may spread to organs adjacent to the • Treatment of dogs with praziquantel liver and other sites. If untreated, AE is fatal. Public health prevention • Meat inspection Animals usually do not present clinical signs for CE and control or AE. • Vaccination of livestock (EG95 vaccine) 2. Water, sanitation and hygiene (WASH) In humans, ultrasonography, validated by CT and/ • Clean community water supply or MRI scans can diagnose both CE and AE cystic • Good personal hygiene following contact with lesions. Biopsies may be helpful to differentiate dogs cysts from tumors and abscesses. Detection of 3. Risk communication Promote safe handling Detection specific antibodies can also support diagnosis. and and disposal of offal, and personal hygiene diagnosis In sheep, diagnosis is made at slaughter. In dogs, can be done by purging, necropsy or copro-Ag. Reference number (FAO) CB1128EN/1/10.20 │ Reference number (OIE) OIE/FPIFS_C&AE/2021.3 │ Reference number (WHO) WHO/UCN/NTD/VVE/2021.3 www.who.int/news-room/fact-sheets/detail/echinococcosis © World Health Organization (WHO), Food and Agriculture Organization of the United Nations (FAO) and World Organisation for Animal Health (OIE), 2021. All rights reserved. i www.oie.int/echinococcosis