Clinical, pathological and serological features of spontaneous canine leptospirosis. An evaluation of the IgM- and IgG-specific ELISA.

The clinical, pathomorphological and serological features of acute canine leptospirosis are evaluated and the IgM- and IgG-specific ELISA for leptospirosis serology in dogs is assessed. The clinical syndrome of acute canine leptospirosis was characterized by depression, anorexia, vomiting and often haemorrhagic diarrhoea. In addition, jaundice, uraemia, elevated creatinine and alkaline phosphatase were observed in the majority of the dogs. In pups invagination of the intestines was a noteworthy finding. The clinical signs and the post-mortem findings were rather non-specific so that the clinical and post-mortem diagnosis had to be confirmed serologically. In acute clinical cases of canine leptospirosis a high anti-leptospiral IgM titre, ranging from 160 in pups to 10240 in adults, was always present, whereas the anti-leptospiral IgG titre and the agglutination titre usually were negative or low. Dogs died from leptospirosis in spite of a high anti-leptospiral IgM titre. Only two dogs having, at the first examination, a high IgM titre in conjunction with a high IgG titre survived an acute infection. The possible role of IgM and IgG in the pathogenesis of an acute leptospiral infection is discussed. Different serological patterns in reference dogs, which were not suffering from acute leptospirosis, are presented.