[A possible mechanism for the endemicity of modern cholera (the role of noncultivated forms of Vibrio cholerae 01)].

The surface water sources of some CIS territories have been screened for cholera toxin genes by the polymerase chain reaction. The vct-genes have been found in the majority of water samples indicating the presence of noncultivated vibrio cholerae cells of an epidemiologic significance. The bacteriological methods failed to isolate the active causative agent of cholera. Additional criteria are proposed for epidemiological typing of territories for cholera. The absence of long deletions or insertions in the vct-genes of noncultivated cholera vibrios has been shown in comparison with analogous gene of the active causative agent of cholera.