This work covers several aspects of the spectrum of outstanding problems that should be approached and solved in order to introduce an effective vaccine against cholera, and which go from the development of one or several stumps with the appropriate attenuation characteristics, until those related to the liberation to the environment of microorganisms genetically modified.

In this case, it is an attenuated stump obtained by genetic manipulation, by means of an ingenious procedure directed to select, in specific way, genes that codify for the choleric toxin and other possible deleterious proteins. This has allowed, for the first time outside the USA, obtaining an attenuated stump of vaccinal candidate Vibrio Cholerae, able to colonize the intestinal mucosa of infant mice and with immunogenic capacity in rabbits, when administering it by intraduodenal inoculation.

On the other hand, as far as we know, it is the first time to be used in the country, in an integral way and under strictly controlled conditions, the experimental challenge in human beings with living microorganisms, completely executing the ethical and methodological norms internationally established for these purposes.

The work is a valid antecedent for future researches which require this type of work experience with human volunteers and guaranteed personal and environmental security.

It was presented the request for international patent in 1998 and these works have been published in: Vaccine, Archives of Medical Research, Lab. Animal Sciences, and Infection and immunity.