CHOLERA - MOLECULAR EPIDEMIOLOGY, PATHOGENESIS, IMMUNOLOGY, TREATMENT, AND PREVENTION

Vibrio cholerae 01 El Tor biotype and the new strain, V. cholerae 0139 Bengal, are responsible for two simultaneous pandemics in Latin Ameri ca and much of Asia, respectively The Latin America V. cholerae strain probably represents an extension of the seventh pandemic into the wes tern hemisphere. Studies on virulence-associated genes and proteins ex pressed by V. cholerae 0139 show that this strain is an O antigen muta nt of an El Tor strain with an array of virulent determinants typical of El Tor biotype 01, and not a non-01 strain that has acquired Virule nce genes by genetic transfer. These virulence factors of cholera stra ins are well characterized at the genetic and physiological level. The pathogenesis of cholera is associated with expression of the coloniza tion factor, Toxin Coregulated Pilus gene tcpA, the Zonula Occludens T oxin gene zot, the Accessory Cholera Enterotoxin gene ace, the Cholera Toxin gene ctxAB, and the global genetic regulatory element toxR. Pro gress in cholera vaccines included several attenuated V. cholerae stra ins being prepared by recombinant DNA techniques, which show a high le vel of immunogenicity. However, more studies are needed to develop non -reactogenic attenuated vaccine strains.