An outbreak of diarrhea caused by bovine viral diarrhea virus (BVDV) infection occurred at a dairy farm in Fukui Prefecture, and one calf was diagnosed as persistently infected (PI) with BVDV. An analysis of cattle movement revealed that the mother cow that produced the PI calf might have been infected with BVDV at a public ranch in the prefecture because the cow had been raised there at around 100 days of pregnancy. An epidemiological investigation did not identify the route of BVDV entry into the public ranch. Genetic analysis of the 5′ untranslated region (5′UTR) and E2 regions of BVDV from the BVD-affected cow and PI calf showed a close similarity to BVDV2a, with a 100% nucleotide sequence match. Molecular phylogenetic analysis of the E2 region indicated that the causative virus of this case was closely related to American isolates and formed a different cluster from previously reported domestic BVDV2a isolates. As there have been no previous reports of domestic strains classified into the cluster, this case is the first report of BVDV classified in such a cluster.

The spleens from 12 broiler chickens 45 to 52 days old that were diagnosed as having chronic congestive spleen during a chicken inspection were subjected to pathological investigation. The spleens were enlarged, weighing 23 to 114 grams, discolored and firm in all 12 cases. On the cut surface showing bulging, their capsules were thickened and pale yellowish tissue dendritically or massively proliferated into the dark-red parenchyma. Histopathologically, the splenic capsules and trabeculae were thickened due to proliferation of fibroblast and collagen fiber. Lymphocytes composing the white pulp were decreased in number, and the dilated red pulp was filled with erythrocytes. Organized thrombi and chronic to subacute inflammation were observed in the intrasplenic branches of the splenic veins in 3 and 2 cases, respectively. The results suggest that the venous lesions were implicated as a contributing factor in chronic congestive spleen in the chickens.