ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2018, Vol. 49 ›› Issue (4): 761-770.doi: 10.11843/j.issn.0366-6964.2018.04.013

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Sequence Analysis of Palyam Serogroup Virus Isolated in South China from 2012 to 2016

YANG Heng1, XIAO Lei1, LI Zhan-hong1, MENG Jin-xin1, YANG Zhen-xing1, LÜ Min-na2, LIN Xu-hui2, LIAO De-fang1, NIU Bao-sheng3, LI Hua-chun1*   

  1. 1. Yunnan Tropical and Subtropical Animal Virus Diseases Laboratory, Yunnan Animal Science and Veterinary Institute, Kunming 650224, China;
    2. Guangdong Open Laboratory of Veterinary Public Health, Guangzhou 510640;
    3. Animal Disease Control Center of Shizong County, Shizong 655799, China
  • Received:2017-09-12 Online:2018-04-23 Published:2018-04-23
  • Supported by:
     

Abstract:

The aim of this study was to isolate and identify the Palyam serogroup virus (PALV) prevalent in China from the sentinel herds and to clarify the relationship between the native strains and the foreign strains. For virus isolation, PALV-positive blood samples were collected from sentinel herds and blind passed on BHK-21 cells. Specific primers targeting Seg-2 and Seg-7 of PALV were designed for identification and sequence analysis of the isolated virus by RT-PCR amplification. Genomic RNA of the isolated virus was extracted from the infected cells and determined by high resolution agarose gel electrophoresis. Cross-reactivity and cross-neutralizing activity of positive sera from different serotypes of PALV were analyzed by immunofluorescence and serum neutralization test. The results were as follows:During 2012 to 2016, a total of 19 strains of PALV were isolated form Yunnan, Guangxi and Guangdong provinces. Seg-2 and Seg-7 sequencing and phylogenetic analysis showed that the Chinese strains of PALV belonged to Chuzan virus (CHUV), D'Aguilar virus (DAV) and Bunyip Creek virus (BCV) and showed closest genetic relationship with the Japanese strains, but showed relative far relationship with the Australian and African strains. High resolution agarose gel electrophoresis showed that the genomic dsRNA of different serotypes of representative PALV strains presenting "3-3-4" banding characteristics. Immunofluorescence results showed that BHK-21 cells infected with CHUV, DAV or BCV presented specific fluorescence when using polyclonal antibody against CHUV as detection antibodies. Serological neutralization tests showed that there was no cross-neutralization protection between the positive sera of CHUV, DAV and BCV viruses. This study reported the molecular characteristics of PALV isolated in China from 2012 to 2016. It's the first time, we reported the DAV and BCV isolated in China. These results will be helpful to better understand the distribution and genetic characteristics of Chinese PALV and provide basis for development of diagnosis reagent and carried out epidemiological and pathogenic research on PALV.

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