There is an ecological cycle that begins with sun light, nutrient run off and warmer water temperatures, which directly effect phytoplankton production. The bloom of phytoplankton is followed by a second, zooplankton bloom that includes the copepods. The indigenous, viable but non-culturable V. cholerae cells have more opportunities to attach themselves when increased surface area is available due to large number of copepods being present in the environment, a situation that occurs during a zooplankton bloom. Within the class Crustacea, the copepoda are the most predominant family present. Copepod species can be found in fresh and salt water.
Most copepods feed on phytoplankton.
Copepods seem to swim continuously, with smooth, steady motions. They occasionally make darting movements as well. They are an important food source for many larger marine creatures. Otto Johansen V. cholerae cells are not visible to the naked eye, but most copepods, although tiny, are visible without a help of a microscope. As most of the V. cholerae cells are attached to copepods, researchers, including Dr. Huq's group, decided to try using a prevention technique that is based on an experience in Africa.