A distemper outbreak in beech martens (Martes foina) in Flanders

An outbreak of distemper was observed in beech martens (Martes foina) in the eastern part of Flanders (Belgium) for the first time. The clinical and pathological findings were consistent with other outbreaks described in mustelids in Europe. Using reverse transcriptase polymerase chain reaction, morbillivirus RNA was detected in an organ homogenate inoculated on Vero.dogSLAM cells. The virus was sequenced and was identified as a canine distemper virus (CDV) strain, hundred percent identical to an earlier isolate from a marten from Germany. After a period of nearly complete absence of beech martens in Flanders due to intensive prosecution, their population density has increased substantially in the last decennia. Although the exact mechanisms behind the observed population changes stay unclear, spread of CDV from central Europe following dispersion of beech martens is indicated by our findings. Further CDV spread could negatively impact on the highly threatened pine marten (Martes martes) and the decreasing polecat (Mustela putorius) populations in Flanders.