Histologic and immunohistochemical studies were carried out on four young cattle with
diabetes mellitus associated with persistent bovine viral
diarrhea (BVD)
virus infection. Clinical findings included persistent
hyperglycemia, decreased
glucose tolerance,
glycosuria,
polydipsia, and severe
emaciation. Macroscopically, multiple erosions and
ulcers in the mucosa of upper and lower alimentary tracts and swollen lymph nodes were commonly observed. Erosions and
ulcers in the mucosa of tongue, esophagus, and forestomach were represented histologically by
necrosis of squamous epithelium with neutrophilic infiltration. In the small and large intestines, villous
atrophy and suppurative cryptitis were often observed, along with diffuse infiltration of lymphocytes and macrophages and fibroplasia in the lamina propria. In the pancreas of all cattle, there was a reduction in the number of islet cells, and most of the residual islet cells had hydropic degeneration and a decreased number of secretory granules. Immunohistochemical examination confirmed that these cells were severely degranulated beta-cells. In addition, many islets containing necrotic islet cells were observed. These islet cells had increased
eosinophilia and shrinkage of cytoplasm, as well as pyknotic nuclei.
Inflammation of the islets with mild infiltration of lymphocytes was observed in all pancreatic lobes. In addition, bovine
IgG-immunoreactive cells were identified immunohistochemically in the affected pancreatic islets. The BVD virus
antigen was not identified in the cytoplasm of the islet cells by immunohistochemical study, although it was identified in the epithelial cells of the small intestine. The histologic and immunohistochemical studies demonstrated that the pancreatic lesions in these animals were similar to those caused by acute
insulin-dependent diabetes mellitus (
IDDM) in human beings.(ABSTRACT TRUNCATED AT 250 WORDS)