Macrocyclops albidus, a freshwater copepod, is an effective ambush predator that shows promise for biological control of container-breeding mosquito larvae.  However, some brackish copepods have been implicated as a host reservoir for the cholera causing bacterium Vibrio cholerae.  Should M. Albidus host pathogenic forms of V. Cholerae, their usefulness as a rational biological pest control would be limited.  This study assesses if, and under what environmental conditions, M. Albidus, serves as a freshwater bacterial reservoir and their viability as a cholera vector. 

Static bioassays lasting 7 days each were performed exposing mature non-gravid M. albidus to alternative salinity, pH and density levels. Mortality rates, including those associated with intraspecies predation, were recorded. Results were compared to similar survival parameters for V. Cholerae.   Thereafter direct fluorescent-monoclonal antibody stains as well as colometric immunoassays were preformed testing the both live and deceased microcosms for the presence of dormant and cultureable V. cholerae.   

Dormant bacterium was detected in assays with pH levels from 6-8 and salinity of .5ppt – 35ppt.  It persisted in brackish assays both with and without live copepods for seven days however in freshwater assays V. cholerae only was detected in the presence of live copepods. Cannibalism by M. Albidus was prevalent.  Copepods were unable to tolerate densities greater than 1/10ml of normal pH however at pH 8 copepods tolerated densities of 2.2/10m. Results demonstrate that M. Albidus is both a host and freshwater reservoir for V. Cholera though the copepods intolerance to density limits their effectiveness as a cholera vector.