Epsilon Archive for Student Projects

Abstract

Trichinellosis is a zoonotic disease that can lead to severe illness and even death in humans. Transmission of larvae occurs with consumption of infected meat. The major sources of infection are pork and wildlife such as wild boar (Sus scrofa) and carnivores. Horses, considered herbivores, have however been responsible for several human outbreaks throughout history. Other herbivores have also been found to be infected by Trichinella.

The Eurasian beaver (Castor fiber) is common in Sweden with numbers reaching 130,000 and an estimated 6,000-9,000 or more are hunted annually. Beavers are strict herbivores, but despite that older findings combined with recent studies from Poland and Latvia show that beavers can become infected with Trichinella. One case of human trichinellosis has been reported with beaver meat being the probable source of infection.

The purpose of this study was to investigate the presence of Trichinella spp. in beavers from Sweden and Norway. A review of current scientific literature revealed no information on similar studies in any of the Nordic countries. In Sweden, beavers are not routinely tested for Trichinella. This study may therefore play a role in establishing the potential need for recommendations regarding beaver meat handling in the future, as well as increase the knowledge of beavers and diseases they may carry. It also raises the question of how infection in beavers occur, since they are considered strict herbivores.

Materials used in this study was beaver meat sent in from hunters throughout Sweden. Hunters participated voluntarily. Front legs including shoulder muscles were the asked for samples, most samples received fulfilled these conditions. A few were missing shoulder muscles, and solitary samples consisted of diaphragm muscle tissue. At the end stages of this study, seven samples collected in Norway were received as part of a scientific collaboration and subsequently added to the results from the Swedish samples.

The method used in this study was artificial digestion with the magnetic stirring method (MSM), according to the EU guidelines.

In total, 58 samples were tested, of which the majority (51) were from different parts of Sweden and some (7) from Norway. No Trichinella spp. was detected.

The method used in this study is considered adequate for detecting Trichinella spp. Despite not finding any Trichinella, possible infection amongst beavers in Sweden and Norway cannot be ruled out. More studies and a larger sample size are needed. For future studies, focusing sampling to areas where Trichinella has been found in other species and systematically collaborating across the Swedish-Norwegian border might give a more thorough insight into the Trichinella-situation amongst beavers and other herbivores.