Between 1991 and 1996, necropsies were performed on 445 harbour porpoises (Phocoena phocoena), in various states of preservation, stranded on German coasts or accidentally caught by German fishermen. The animals originated from the North and Baltic Seas, and 133 were considered suitable for histopathological, immunohistochemical and microbiological examination. Most of the lesions in these 133 porpoises were caused by parasites, in particular in the respiratory tract, two-thirds of the animals exhibiting pneumonia associated with the parasites. Pneumonia was considered to be the cause of death in 46% of the stranded subadult and adult animals. The findings gave no evidence of any epidemic due to bacterial or viral infection. Bacteriological examination suggested that pneumonia was mainly caused by secondary bacterial infection and not by parasitic infestation alone. Beta-haemolytic streptococci were considered to be the main infectious agents. Morbillivirus antigen was not detected immunohistochemically.
Bibliographical noteFunding Information:
The study was funded by the German Federal Ministry of Environment and the German Federal Ministry of Research and Technology. Microbiological investigations were in part performed by Dr Irene Blaha, parasitological analysis by Dr Roland Lick and age determination by Dr Laura Chàvez-Lisambart and Dr Hartwig Kremer. We are indebted to numerous fishermen, seal hunters and environmental organizations for supplying carcasses. We thank Heather Caprette (Veterinary Technology Services, Ohio State University) for assistance with illustrations and Dr Steven Weis-brode (Department of Veterinary Biosciences, Ohio State University) for reviewing the manuscript.