Lymphoid neoplasms of abdominal cavity origin were found in two cows infected with bovine leukemia virus (BLV). Case 1 was a 3-year-old Japanese Black cow affected with a B-1 B cell lymphoma. Case 2 was a 14-year-old Japanese Black cow that developed a γδ T cell lymphoma. Immunohistochemically, CD79a-positive lymphoma cells were observed in case 1, whereas CD3-, WC1-or perforin-positive ones were seen in case 2. Despite the expression of CD5 in both lymphomas, the reactivity was surface or cytoplasmic in case 1 and surface membrane in case 2. Erythrophagia by tumor cells of both cases was considered to be due to the fact that their normal counterparts were more primitive forms than conventional lymphocytes.Discipline: Animal health Additional key words: B-1 B cell, CD5, γδ T cell JARQ 41 (2), 153 -156 (2007)

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A total of 568 normal feces from calves on a beef farm in Fukui Prefecture, Japan, in 2011–2012 were examined by RT-semi-nested PCR for rotavirus A (RVA) VP4 genes. Through partial sequencing and BLAST analyses of 84 VP4-positive specimens, we identified an avian-like RVA strain, N2342, which shares highest nucleotide identity (80.0%) with known avian-like bovine strain 993/83, in one specimen. Phylogenetic analysis also revealed a close genetic relationship between N2342 and avian RVAs, suggesting bird-to-cattle transmission. We observed frequent contact of wild birds with calves in the farm, suggesting that these birds were the source of the virus.

We describe here isolation of genetically atypical serotype 6 Actinobacillus pleuropneumoniae in Japan indistinguishable by the multiplex PCR that can discriminate between immunologically cross-reactive serotypes 3, 6 and 8. Nucleotide sequence analysis of capsular export and biosynthesis genes revealed that the atypical isolates have capsular polysaccharide export and synthesis gene sequences that are distinct from those of the serotype 6 reference strain. The atypical strains contain a sequence that is identical with both serotype 3- and 6-specific primers, which causes cross-reactions in multiplex PCR.