A novel Spiroplasma pathogen causing systemic infection in the crayfish Procambarus clarkii (Crustacea: Decapod), in China

Authors

  • Wen Wang,

    Corresponding author
    1. Jiangsu Key Laboratory for Bioresources Technology, College of Biological Sciences, Nanjing Normal University, Nanjing 210097, PR China
    2. Department of Biological Science and Technology, Nanjing University, Nanjing 210093, PR China
      *Corresponding author. Tel.: +86 25 83805988; fax: +86 25 83598723., E-mail address: njnuwang@263.net
    Search for more papers by this author
  • Wei Gu,

    1. Jiangsu Key Laboratory for Bioresources Technology, College of Biological Sciences, Nanjing Normal University, Nanjing 210097, PR China
    Search for more papers by this author
  • Zhengfeng Ding,

    1. Jiangsu Key Laboratory for Bioresources Technology, College of Biological Sciences, Nanjing Normal University, Nanjing 210097, PR China
    Search for more papers by this author
  • Yalai Ren,

    1. Jiangsu Key Laboratory for Bioresources Technology, College of Biological Sciences, Nanjing Normal University, Nanjing 210097, PR China
    Search for more papers by this author
  • Jianxiu Chen,

    1. Department of Biological Science and Technology, Nanjing University, Nanjing 210093, PR China
    Search for more papers by this author
  • Yayi Hou

    1. Lab of Immunology in Medical School, Nanjing University, Nanjing 210093, PR China
    Search for more papers by this author

  • Edited by R.Y.C. Lo

*Corresponding author. Tel.: +86 25 83805988; fax: +86 25 83598723., E-mail address: njnuwang@263.net

Abstract

A novel disease of crayfish Procambarus clarkii appeared in the summer of 2004 in freshwater aquaculture in Jiangsu province of China. Light and transmission electron microscopy (TEM), molecular biological methods and in vitro culture were used to identify the pathogen. The agent was unique in having a helical morphology and rotary motility as observed by phase-contrast light microscopy and was found in haemolymph, muscles, nerves and connective tissues by smear method and TEM. Ultra-thin sections under TEM revealed the wall-free membrane of the microbe. The agent could pass through membrane filters with pores 220 nm in diameter and was cultivated in vitro in M1D medium. 16S rDNA of the crayfish pathogen was amplified by PCR using primers specific for Spiroplasma-specific 16S rDNA. The resultant 271 bp PCR product showed 99% identity with Spiroplasma mirum 16S rDNA, having a close relationship with the spiroplasma from the Chinese mitten crab Eriocheir sinensis. This is the second time a spiroplasma has been found in a freshwater crustacean. The 271 bp PCR product was also amplified from the bottom mud in the ponds associated with the disease. The PCR molecular method is an effective way to detect spiroplasma in freshwater environment. The results from this study are significant in expanding the host range of spiroplasma and freshwater ecology.

Ancillary