Echinococcus medication required on dogs entering Finland found to be justified

21.2.2017 08:54

The Finnish Food Safety Authority Evira participated in a literary study tracing Echinococcus multilocularis in final and intermediate hosts in the European Union and adjacent areas. The study provides a scientific basis for requiring Echinococcus medication on dogs entering a country free from parasitic infection, such as Finland. Dogs moving around with people may spread the infection to new areas. For the time being, the parasite has not been found in Finland, although it has been actively searched for.

The Echinococcus multilocularis parasite, which causes serious illness in humans, has been spreading dramatically in Europe during the past few decades. To determine the grounds for exemption, the European Commission asked the European Food Safety Authority (EFSA) to examine the scientific basis for the freedom from disease in host animals", says Professor Antti Oksanen, DVM (PhD), Evira. Oksanen led a sub-project focusing on the geographical distribution and prevalence of the parasite in Europe.

Does Echinococcus multilocularis not prosper in the Nordic Countries?

There are suitable final and intermediate hosts for the E. multilocularis parasite in Nordic nature. The study gives reason to assume, however, that for some reason the parasite does not thrive in the North. Echinococcus multilocularis is common in Estonia and Spitsbergen, but rare in Sweden.

"One reason may be that the chain of infection between the main and intermediate hosts is broken. Another equally good assumption is that the parasite is only just beginning to establish itself in the North. In Sweden, approximately one per mille of foxes are infection carriers. Time will tell", says Oksanen.

The study confirmed that the red fox is the primary host of Echinococcus multilocularis in Europe. Other significant hosts include the raccoon dog, the jackal and the wolf. If there is no infection in the foxes in a region, other canines are not infected, either. In Spitsbergen, where the red fox is not found, the main host is the Arctic fox.

The most significant intermediate hosts are rodents of the subfamily Arvicolinae, including the muskrat. Murines, such as mice and rats, have been studied so little that the information available is insufficient.

The research group had a massive task

The working group studied nearly 3,000 scientific publications on E. multilocularis infections. Most publications could be screened out as duplicates or because the abstract indicated, for example, that the publication concentrated on infections in humans. The working group eventually read 402 publications, of which 255 were found relevant and used in the final analysis.

Europe-wide prevalence of the parasite by host animal was determined based on a quantitative meta-analysis based on 244 publications. In the analysis, the results of earlier individual studies were combined and, based on them, the quantitative prevalence of the E. multilocularis parasite by host animal in Europe was deduced.

"The study traced the prevalence of the parasite in final and intermediate hosts in the European Union and adjacent countries by means of a method known as the systematic review. The advantage of this method is that by combining up to several hundred separate research results, we get strong evidence of cause-and-effect relations. A disadvantage is, perhaps, that we could not really expect the study to reveal anything new", says Oksanen.

The systematic review is based on a systematic study of all previously published scientific and "grey" information. Grey literature refers to matter-of-fact documentation that may not have been subjected to normal scientific peer evaluation. It includes, for example, official reports, meeting publications and some dissertations.

The results of the study financed by EFSA were announced in a publication subjected to scientific peer evaluation:
Oksanen, A., Siles-Lucas, M., Karamon, J., Possenti, A., Conraths, F.J., Romig, T., Wysocki, P., Mannocci, A., Mipatrini, D., La Torre, G., Boufana, B., Casulli, A.
The geographical distribution and prevalence of Echinococcus multilocularis in animals in the European Union and adjacent countries: a systematic review and meta-analysis. Parasites & Vectors 2016: vol. 9, No. 519. 

Read more:
Frequently asked questions about Echinococcus medication

For further information, please contact:
Antti Oksanen, DVM (PhD), veterinary bacteriology and pathology, wild and aquatic animal pathology, tel. +358 44 561 6491


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