From the National Institute of Allergy and Infectious Diseases. Summary of the 19th United States-Japan Joint Cholera Conference.

Classical cholera has reappeared in Asia after a 20-year hiatus, reminding us that we still have much to learn about the epidemiology of this disease. The unexpected recovery of V. cholerae from nonendemic estuarine waters suggests that the continued occurrence of clinical cholera may not be entirely dependent on repeated contamination of environmental waters by man. Of critical importance has been the discovery and partial characterization of new enterotoxins produced by V. cholerae and ETEC, a finding that further complicates the already complex problem of fully elucidating the virulence mechanism of these organisms. The recent purification of Shiga toxin is beginning to provide clues as to its structure, function, and possible pathogenic role in EPEC-related hemorrhagic colitis and diarrhea. The conversion of virulent V. cholerae into less virulent strains by genetic engineering provides hope for the ultimate development of safe and effective live oral cholera vaccines. Intestinal Peyer's patches process living and killed enteropathogens differently, and this discovery may afford insights into ways to improve antigen potency. Enterotoxins differ fundamentally in their biochemical effects, and not all of them evoke active electrolyte secretion by altering cyclic-nucleotide levels in mucosal cells. Finally, the mucosal response to a protein toxin may be under some genetic control. The complete proceedings of this conference will be published by KTK Publishers (Tokyo). The next Joint Conference on Cholera has been scheduled for early November 1984 in Nara, Japan.