[Prevalence of anti-Yersinia antibodies in European brown hares in North-Rhine Westphalia, Germany]. / Prävalenz von Anti-Yersinia-Antikörpern bei Feldhasen in Nordrhein-Westfalen.

Yersinia (Y.) pseudotuberculosis infections may lead to significant lethality in European brown hare (Lepus europaeus, Pallas) populations especially during the cold and wet seasons. In recent decades, also Y. enterocolitica was isolated from hares found dead. Consequently, a Western-blot technique proved to be valuable for the detection of antibodies against all pathogenic Yersinia isolates was applied to monitor the prevalence of antibodies in hare populations in North-Rhine Westphalia, Germany. A total of 89.6% of the 230 animals tested was seropositive. Further investigations should be performed to elucidate the role of subclinical yersiniosis in the decline of European brown hare populations in Germany.

[Relations between fox populations and halting the rabies in North Rhine-Westphalia]. / Relations entre population de renards et limitation de la propagation de la rage en Rhénanie-Westphalie.

Since Sylvatic rabies started in North Rhine-Westphalia in 1953 many epidemics have occurred, only in mid-mountain areas. As a characteristic, epidemics halted, in each case at the limit between big game (in south-east) and small game (in the north-west) hunting areas. The fact that rabies died out when reaching these limits is surprising for, according to the number of foxes killed in small game hunting areas, there was a fox density which usually does not allow the epidemic to stop. Explanation of this phenomenon could be the different hunting methods. Indeed in small game hunting areas 80% of killed foxes are cubs or sub-adults. Which means that most of the growing population is destroyed early enough, in contrast with big game hunting areas where less than half of the killed foxes are cubs or sub-adults. This is why in big game hunting areas, better conditions are found for rabies appearance than in the other type of hunting area. Studying the number of foxes killed, these relations are described for three regions of North Rhine-Westphalia. It is obviously very important in rabies control that, besides other measures, growing foxes are killed in priority.