Quantitative detection and proliferation dynamics of a novel Spiroplasma eriocheiris pathogen in the freshwater crayfish, Procambarus clarkii.

Spiroplasma eriocheiris disease control based on sensitive quantitative methods has become a priority. A SYBR Green real-time PCR that can simultaneously detect and quantify S. eriocheiris in the freshwater crayfish Procambarus clarkii was produced and evaluated. In the asymptomatic crayfish, hemolymph exhibited the statistically greatest number of S. eriocheiris copies indicating a tissue-specific pathogen infection characteristic. The curve of the pathogen amount change in vivo assumed a very similar shape with the typical one-step growth curve. A turning point from chronic infection to acute infection was suggested from 3 to 4 days when the S. eriocheiris copies in hemolymph increased substantially.