豚サーコウイルス2型感染を伴い多核巨細胞浸潤
を特徴とする子豚のび漫性肝臓壊死

奥田宏健^1）†　　白石　誠^2）　　吉村範男^3）　　多田幸四郎^1）　　福冨豊子^1）
萱原佳美^1）　　播谷　亮^4）　　川嶌健司^5）　　村上洋介^4）

要　　　　　約 　発育不良の若齢子豚1頭を病理組織学的に検索したところ，肝臓にび漫性の壊死，偽胆管形成，多核巨細胞，マクロファージおよびリンパ球浸潤が観察された．多核巨細胞，マクロファージおよびクッパー細胞の細胞質内に，免疫組織化学的には豚サーコウイルスに対する陽性抗原が存在し，in situ hybridization検査では離乳後多臓器性発育不良症候群（postweaning multisystemic wasting syndrome; PMWS）の病原体として疑われている豚サーコウイルス2型（pmwshPCV）核酸が検出された．透過型電子顕微鏡検査では，サーコウイルス様粒子がマクロファージや多核巨細胞の細胞質内に観察された．また，PCR法でも，この豚の肝臓および回腸においてpmwshPCV核酸が検出された．pmwsh PCV感染と関連していると考えられているPMWSでは肝臓の壊死や線維化が時に観察されるが，本症例の肝臓病変はそれらと比較し重度であり，多数の巨細胞の出現がきわめて特徴的であった． ―キーワード：肝臓壊死，豚サーコウイルス，離乳後多臓器性発育不良症候群． --------------------日獣会誌　54，181〜184（2001） Diffuse Hepatic Necrosis Characterized by Infiltration of Multinucleated GiantCells Associated with Porcine Circovirus Type 2 in a Piglet Koken OKUDA＊†, Makoto SHIRAISHI, Norio YOSHIMURA, Koshiro TADA,Toyoko FUKUTOMI, Yoshimi KAYAHARA, Makoto HARITANI,Kenji KAWASHIMA and Yosuke MURAKAMI ＊Okayama Prefectural Veteminary Diagnostic Laboratory, 2770h1 Kawachi, Mitsu, Okayama Prefecture 709h2123, Japan SUMMARY   Histopathological examination of a stunted piglet revealed diffuse hepatocytic necrosis and pseudo bile ducts formation together with infiltrations of multinuclear giant cell, macrophage, and lymphocyte in the liver. The immouno-histological method demonstrated the porcine cirocovirus antigen in the cytoplasm of giant cells, macrophages, and Kupffer cells. In situ hybridization revealed the presence of genetic signals specific to the porcine circovirus type 2 (pmws-PCV), which has been suspected of being the pathogen in the post-weaning multisystemic wasting syndrome (PMWS). Electron microscopy revealed circovirus-like particles in macro-phage and multinuclear giant-cell cytoplasm. Moreover, the PCR method detected the nucleotide specific for pmws-PCV in the animalﾕs liver and ileum. Although hepatic necrosis and fibrosis have occasionally been observed in animals with PMWS associated with pmws-PCV infection, in this case, the extent of hepatic lesions was more prominent than in previously reported cases. Furthermore, the appearance of many giant cells and pseudo bile ducts was especially remarkable in this piglet ―Key words : liver necrosis, porcine circovirus, postweaning multisystemic wasting syndrome. †　Correspondence to : Koken OKUDA (Okayama Prefectural Veteminary Diagnostic Laboratory) 2770-1 Kawachi, Mitsu, Okayama Prefecture 709-2123, JapanTEL 0867-24-3855　FAX 0867-24-3856 --------------------J. Jpn. Vet. Med. Assoc., 54, 181〜184 (2001)