A spiroplasma associated with tremor disease in the Chinese mitten crab (Eriocheir sinensis)

• DOI: 10.1099/mic.0.26664-0
• Publication Date: 2004-09-06T23:52:38Z
• Authors: Wen Wang; Bohai Wen; Gail E. Gasparich; Ningning Zhu; Liwen Rong; Jianxiu Chen; Zaikuan Xu
• Keywords: Spiroplasma; Penaeus monodon; Chinese mitten crab; Embryonated; Yolk

An epidemic of tremor disease has been a serious problem in Chinese mitten crabs, Eriocheir sinensis , China recent years. The disease-causing agent was previously considered to be rickettsia-like organism. Here, analysis the 16S rRNA gene sequence, light and electron microscopy cultivation vitro were used identify agent. Sequence found it have 98 % identity with that Spiroplasma mirum . able passed through membrane filters pores 220 nm diameter could cultivated by inoculating yolk sac embryonated chicken eggs M1D medium. Rotary motion flexional movement seen microscopy, showed organism had helical morphology lacked cell wall. produced small colonies 40–50 μm after 17–25 days incubation on solid blood cells, muscles, nerves connective tissues crabs inoculated filtrate sacs or cultures grown medium, similar structure those broth. Disease reproduced experimental infection organisms. This study demonstrated causative crab is member genus believed first time spiroplasma crustacean. These findings are not only significant for studies pathogenic spiroplasmas, but also implications freshwater ecology.