Yoneyama Shuji, Hayashi Tsuyoshi, Kojima Hirokazu, Usami Yoshihide, Kubo Masanori, Takemae Nobuhiro, Uchida Yuko, Saito Takehiko
Central Animal Hygiene Service Center of Tochigi Prefecture.
J Vet Med Sci. 2010 Apr;72(4):481-8. doi: 10.1292/jvms.09-0342. Epub 2009 Dec 25.
In February 2008, a feeder pig herd of the affected farm in Tochigi Prefecture, Japan, showed increasing respiratory symptoms; by April, the situation worsened with 12-16 pigs dying daily. Diagnostic tests revealed the presence of H1N2 subtype of swine influenza virus (SIV) and Pasteurella multocida from nasal swab and lung emulsion. Serological tests by hemagglutination inhibition method and enzyme-linked immunosorbent assay method (ELISA; imported from U.S.A.) indicated the spread of SIV into the pig herds of the affected farm around April 2008. The severe infection and subsequent damage were considered as a result of the combined infection of SIV (H1N2) and bacteria that may have been prevalent in the pig farm. Genetic homology search of sequences for the hemagglutinin (HA) and neuraminidase (NA) genes of A/swine/Tochigi/1/08 showed high homology to Japanese SIVs (H1N2) isolated in the 2000s. Therefore, we considered that Japanese SIV (H1N2) has established an independent stable lineage and participated in infecting pig populations as one of the factors of the pig respiratory disease complex. Consistent surveillance would contribute to clarifying the prevalence of dominant SIVs.
2008年2月，日本枥木县受影响猪场的一批育肥猪出现呼吸道症状增多的情况；到4月时，情况恶化，每天有12 - 16头猪死亡。诊断检测从鼻拭子和肺乳剂中发现了猪流感病毒（SIV）H1N2亚型和多杀性巴氏杆菌。通过血凝抑制法和酶联免疫吸附测定法（ELISA；从美国进口）进行的血清学检测表明，SIV在2008年4月左右在受影响猪场的猪群中传播。严重感染及后续损害被认为是SIV（H1N2）与该猪场可能普遍存在的细菌合并感染的结果。对A/猪/枥木/1/08的血凝素（HA）和神经氨酸酶（NA）基因序列进行的遗传同源性搜索显示，其与2000年代分离出的日本SIV（H1N2）具有高度同源性。因此，我们认为日本SIV（H1N2）已建立起独立稳定的谱系，并作为猪呼吸道疾病综合征的因素之一参与感染猪群。持续监测将有助于明确优势SIV的流行情况。
