Scientific background concerning Echinococcus multilocularis. Muza Kirjušina, Daugavpils University, Latvia

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1 Scientific background concerning Echinococcus multilocularis Muza Kirjušina, Daugavpils University, Latvia

2 Echinococcus multilocularis Infection with the larval form causes alveolar echinococcosis (AE). Humans are infected either by direct contact with difiniteve hosts or inderectly by intake of contaminated water or contaminated plants such as wild berries. Frequently asymptomatic during 5-15 years (difficulty to identify the time and the region of infection). Larvae can migrate to anywhere (liver is the most common place). Vaccines are not available for people. Fatal when untreated. Meilinger et al. Parasites & Vectors 2013, 6:287

3 Clinical Signs The primary lesion of E. multilocularis is almost always in the liver, and the course of the disease is slow. During the early stages, the infection is usually asymptomatic. Larger tumors cause hepatomegaly and epigastric pain. Ascites, malnutrition, jaundice and signs of hepatic failure may occur in later stages of disease. E. multilocularis cysts are very dangerous as they are not enclosed within a membrane and invade tissues by budding outward; alveolar hydatidosis is progressive and malignant. The cysts can spread to nearby organs and metastasize to the brain, lungs, mediastinum and other organs or tissues. Sometimes, the primary cyst dies early in its development, and remains asymptomatic.

4 Taxonomy Class Cestode Order Cyclophyllidea Family Taeniidae Genus Echinococcus Species Echinococcus multilocularis Others species: E. granulosus sensu lato (G1-G10) E. oligarthus Wild felids (no mature in dogs), few reports of human diseases, E. vogeli Bush dog, zoonotic E. shiquicus Tibetan foxes. Zoonotic potential unkown

5 Echinococcus multilocularis distribution in Europe Country codes: 1 - Denmark; 2 - Sweden; 3 - Estonia; 4 - Latvia; 5 - Lithuania; 6 - Italy; 7 - Slovenia; 8 - Hungary; 9 - Romania.

6 Echinococcus multilocularis life cycle Definite hosts - usually foxes and canines Intermediate hosts - small rodents

7 Diagrammatic representation of Echinococcus metacestodes

8 Diagnostic Definitive host Sedimentation and counting technique (SCT) Intestinal scraping technique (IST) Shaking in a Veseal technique (SVT) A B A Oval (30-40μm), presence of hook, identical for all the Taenia genus High resistance to freezing (except -80 C), sensitive to drying Potentially survival in environment +1year (humid, +4 to +15 C) B Length 1.2 to 4.5 mm, mainly 4-5 segments (2-6) Last segment with mature eggs ( ) Intermidiate host Difficult magnetic resonance imaging (MRI) or CT Treatment surgical resection

9 Diagnostic Coproantigen ELISA In vivo and post mortem diagnosis. Faecal samples Sensitivity (60-95%), Specificity (70-99%) PCR Faecal samples, liver and organ cysts Sensitivity (82-84%), Specificity (100%)

10 Echinococcus multilocularis prevalence in definitive hosts in Europe Fox vary from low (<10%) to high (>50%) Presence of urban foxes generally less infected than in rural areas Dog generally low <1%, up to 5% locally in high endemic areas Cat very few data, <0.5%

11 Definitive hosts Biotic Environmental Remark potential contamination Fox good Major role Main definitive host Raccoon good Minor role definitive host dog Dog good Minor role lower numbers of worms but higher longevity Cat good Negligible role eggs non infective experimentally Intestinal longevity: 3 to 4 months

12 Prevention and control Alveolar echinococcosis prevention and control is more complex as the cycle involves wild animal species as both definitive and intermediate hosts. Regular deworming of domestic carnivores that have access to wild rodents, should help to reduce the risk of infection in humans. Culling of foxes and unowned free-roaming dogs is applicable but appears to be highly inefficient. Deworming of wild and stray definitive hosts with anthelminthic baits resulted in significant reductions in alveolar echinococcosis prevalence in European and Japanese studies. Sustainability and cost benefit effectiveness of such campaigns are, however, controversial.

13 Prevention and control Reducing wildlife hosts (fox, rodents): hard to accomplish on a large scale, ecologically unaccepted, and concerns animal welfare. Fox baiting: long-term baiting campaigns most effective tool to significantly decrease pressure of spreading infection of parasite eggs. Dog deworming: regular deworming of domestic carnivores that have access to wild rodents should help to reduce the risk of infection in humans.

14 Human prevention Complete exposure prevention to Echinococcus spp. eggs from wild animals is difficult; however, food safety precautions, combined with good hygiene, can be helpful. All fruits and vegetables, particularly those picked in the wild, should be washed thoroughly to remove any eggs. Fences should be placed around vegetable gardens to keep animals, especially dogs and wild carnivores, away. Hands should always be washed after handling pets, farming, gardening or preparing food. Untreated water from sources such as lakes may also contain Echinococcus eggs, and should be avoided. Anyone who handles the definitive hosts or material that canbe contaminated with eggs should use appropriate personal protective equipment.

15 Role of dog in Echino Environmental contamination Source of human infection

16 Scheme for preventive health measure The pet animal (dog only) must, prior to entering Finland, Ireland, Malta or the United Kingdom, or Norway, be treated against the parasite E. multilocularis in accordance with Commission Delegated Regulation (EU) No 1152/2011, as follows: 1. The treatment must be administered by a veterinarian within a period of not more than 120 hours and not less than 24 hours before the time of scheduled entry 2. The treatment must be certified by the administering veterinarian in the relevant section of the passport.

17 Thank you for attention!