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Licensed Unlicensed Requires Authentication Published by De Gruyter April 13, 2018

Genotyping and virulence analysis of Toxoplasma gondii isolates from a dead human fetus and dead pigs in Jiangsu province, Eastern China

Zhaofeng Hou, Yonghua Zhou, Dandan Liu, Shijie Su, Zhenxing Zhao, Jinjun Xu and Jianping Tao
From the journal Acta Parasitologica


Toxoplasma gondii is an obligate intracellular parasite with worldwide distribution. Virulence of T. gondii is a multigenic trait. Genetic and virulence data for T. gondii isolates from humans and animals in China have been reported. However, almost all biological materials used for genotyping of T. gondii from humans and pigs were DNA samples prepared from tissues, and T. gondii strains used for virulence analysis were isolated mainly from cats. In this study, one isolate from a dead human fetus was identified as type I (ToxoDB #10) while the two isolates from dead pigs were type Chinese I (ToxoDB #9) with PCR-restriction fragment length polymorphism using 10 markers (SAG1, SAG2, SAG3, BTUB, GRA6, c228, c292, L358, PK1 and Apico). Three isolates were comfirmed as virulent strains in mice. By cloning and sequences analysis, all isolates contained a Pvu II restriction site (572–577 bp) in the KHB fragment and five tandem repeats in the 5′ UTR region of SAG1, which were associated with T. gondii virulence. The type Chinese I isolates contained two deletions of 15 and 3 bp at positions 635 to 649 and 658 to 660 in the GRA6, which were correlated with genotype, but not with virulence. To our knowledge, this is the first report on the systematic analysis of murine virulence of type Chinese I strain from pigs, and the associations of sequences of the KHB fragment and SAG1 with virulence of type Chinese I strain. The Chinese I genotype was more closely related to type II strains.

  1. Ethical statement: All mice were treated in strict accordance with the recommendations of the Guide for the conduct of studies with experimental animals of the People’s Republic of China. The study protocol was approved by the Animal Care and Use Committee of the College of Veterinary Medicine, Yangzhou University (Approval ID: SYXK [Su] 2012-0029). All efforts were made to minimize numbers and to reduce suffering of the animals used.


We thank Professor Qijun Chen (College of Animal Science & Veterinary Medicine, Shenyang Agricultural University) for a kind gift of DNA samples of the ME49 strain. This study was supported by the funding from the Open Project Program of Jiangsu Key Laboratory of Zoonosis (R1507), a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and the University Graduate Scientific Research Innovation Program of Jiangsu Province (CXLX_1431).


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Received: 2017-10-24
Revised: 2018-2-22
Accepted: 2018-2-28
Published Online: 2018-4-13
Published in Print: 2018-6-26

© 2018 W. Stefański Institute of Parasitology, PAS