INFECTIOUS-DISEASES AS MAIN CAUSES OF MORTALITY TO BEAVERS CASTOR FIBER AFTER TRANSLOCATION TO THE NETHERLANDS

Between 1988 and 1994, 58 beavers were translocated from the Elbe regi on (Germany) to the Netherlands. In 43 animals, radio-transmitters wer e implanted with a pulse interval which was dependent on body temperat ure; subsequently, 22 of the released animals were found dead and the cause of death was investigated. Infectious diseases were the most imp ortant cause of death (50%), in particular yersiniosis and leptospiros is. Yersiniosis is relatively rare in the source population along the Elbe, and leptospirosis has not been reported before in beavers. We hy pothesize that the immune system of the translocated animals was weake ned by stress at a time of exposure to new pathogens. In future transl ocations of beavers, we recommend to reduce the stress, improve the hy giene, and to vaccinate against Yersinia pseudotuberculosis and leptos pirosis prior to the release.