Alaria alata - Analysis, prevalence and risk assessment

Alaria (data is a trematode, the adult of which is found in carnivores throughout Europe and Asia. The mesocercarial stage of the trematode (Duncker'scher Muskelegel, DME) can infect paratenic hosts, such as many sorts of mammalians, birds, reptiles, and amphibians. Especially omnivores such as wild boars can become paratenic host as they ingest the second intermediate hosts of the parasite (water snails and frogs/tadpoles) as well as infected small rodents, reptiles and amphibians. The pathological consequences of human alariosis have been described for Alaria americana. Since 2002 an increasing number of findings of Alaria alata mesocercariae in meat of wild boars in different parts of Germany as well as in other European countries such as France, Croatia and Poland during official meat inspection for Trichinella initiated a reassessment of the potential foodborne human health risk posed by this parasite. In view of the insufficient data regarding A. alata, a final risk assessment could not be performed. This is mainly because a specific and sensitive detection method was missing. So, our own studies concentrate on (1) the development, optimization and validation of methods for reliable DMS detection, (2) the distribution of the mesocercariae within their paratenic hosts, i.e. identification of potential predilection sites, particularly in wild boars, (3) their prevalence in sylvatic populations of animals with respect to their introduction into the human food chain, and (4) assessment of the risk for man arising from alimentary and ocular infections with Alaria alata mesocercariae. This contribution is mainly concerned with method development and optimisation.