V. cholerae’s primary reservoir is an aquatic environment, where it exists in a free-living state associated with phytoplankton, zooplankton, algae, or copepods (12, 13). Transmission into a host’s gastrointestinal system occurs by ingestion of contaminated food or water. Bacteria surviving the acidity of the stomach colonize the small intestine and cause increased intestinal secretions, leading to large volumes of watery diarrhea (14). V. cholerae exits the human body during such diarrheal purges, allowing disease transmission or seeding an environmental reservoir.