Virulence evaluation of classical swine fever virus subgenotype 2.1 and 2.2 isolates circulating in China

Publication date: Available online 3 April 2019Source: Veterinary MicrobiologyAuthor(s): Wenjie Gong, Junhui Li, Zunbao Wang, Jiumeng Sun, Shijiang Mi, Zongji Lu, Jian Cao, Zhihua Dou, Yanjun Sun, Pengjiang Wang, Ke Yuan, Liying Zhang, Xubin Zhou, Sun He, Changchun TuAbstractClassical swine fever (CSF) remains an important pig disease in China, where it usually presents with mild or atypical clinical manifestations, with large scale outbreaks rarely seen. This has led to speculation about the possible circulation of viral strains of low virulence. To investigate this possibility, five field isolates within the predominant genotype 2 (2.1b, 2.1c, 2.1 h and 2.2) were evaluated and compared by experimental infection of naturally farrowed but colostrum-deprived piglets. All infected piglets displayed clinical signs, including persistent high fever, depression, anorexia, dyspnea, conjunctivitis, constipation, and hesitant gait. Typical pathological lesions, including pulmonary edema, hemorrhagic or cellulosic exudation, and swelling and hemorrhage of lymph nodes, were observed. Viremia and Erns protein expression in the blood of all infected animals were detectable from 3-5 days post infection (DPI), their presence correlating with the onset of fever, clinical signs and leukopenia. E2 antibody did not develop in any of the field CSFV-infected piglets during the disease course, while Erns antibody was detectable in 4-56% of infected animals at various time points. Mortalities ran...
Source: Veterinary Microbiology - Category: Veterinary Research Source Type: research