2018 Volume 71 Issue 2 Pages 89-94
In this study, we pathologically analyzed a clinical case of Histophilosis or a Histophilus somni -associated disease that occurred in Yamagata Prefecture, Japan. An isolate from a heart lesion and two past isolates (from encephalitis and from pneumonia) were analyzed for the antigen type of the major outer membrane protein (MOMP) and cytotoxicity to EBTr cells. Pathognomonic dissection found a villous heart, and histopathological examination revealed fibrinous pericarditis. MOMP antigen typing showed that isolates from this case and pneumonia were classified as type 3c, and the isolate from encephalitis was type 1. In the experiment on the cytotoxicity of the three isolates to EBTr cells, the isolate from encephalitis was a strong cause of cellular impairment. On the other hand, cellular impairment of the other two isolates was diminished. These results suggest that the cytotoxicity of the isolate from this case is weaker than the isolate from encephalitis, and the weak cytotoxicity caused the villous heart, resulting from a chronic process.
