Association of Vibrio Cholerae O1 El Tor and O139 Bengal with the Copepods Acartia Tonsa and Eurytemora Affinis

The association of Vibrio cholerae with zooplankton has been suggested as an important factor in transmission of human epidemic cholera, and the ability to colonize zooplankton surfaces may play a role in the temporal variation and predominance of the two different serogroups (V. cholerae O1 El Tor and O139) in the aquatic environment. To date, interactions between specific serogroups and species of plankton remain poorly understood. Laboratory microcosm experiments were carried out to compare quantitatively the colonization of two copepod species, Acartia tonsa and Eurytemora affinis, by each of the epidemic serogroups. V. cholerae O1 consistently achieved higher abundances than V. cholerae O139 in colonizing adults of each copepod species as well as the multiple life stages of E. affinis. This difference in colonization may be significant in the general predominance of V. cholerae O1 in cholera epidemics in rural Bangladesh where water supplies are taken directly from the environment.