Isolation of E. coli phages from environmental water samples and analysis of their effect on periodic epidemics of cholera

Abstract

Cholera is a deadly infectious disease caused by the pathogen Vibrio cholerae. In our country cholera epidemics occur seasonally. Two peaks of outbreaks nicely coincide with dry season and monsoon rain. Several factors control the outbreaks to occur and collapse. Bacteriophages are one of them which have been reported to trigger the collapse of the outbreaks. The concentration of the Vibrio cholerae specific bacteriophages is inversely correlated with the concentration of Vibrio cholerae in the environment. Therefore these bacteriophages probably play an important role in controlling the epidemics to occur or collapse. It is still not clear what factors trigger the onset of cholera outbreaks. There are numerous amounts of other species of bacteria and viruses in the environment that could influence the cholera epidemic to start. This study was design to see the effect of E. coli bacteriophages on the epidemics of cholera. Routine isolation and estimation of E. coli phages reveal that pathogenic E. coli phage concentration is proportional to O1 Vibrio cholerae (pathogenic) phage concentration. The concentration of nonpathogenic E. coli phages does not oscillate like pathogenic E. coli phages. Therefore the oscillating abundance pattern of pathogenic E. coli phages might control the concentration of pathogenic E. coli which in turn controls the Vibrio cholerae count by some yet unknown mechanism.