ALGAL BLOOMS IN THE SPREAD AND PERSISTENCE OF CHOLERA

Cholera has been long associated with the seasonality of coastal algal blooms off Bangladesh. Using fluorescent antibody (FA) techniques, mi crobiologists have now identified a viable, non-cultivable form of Vib rio cholerae in a wide range of marine life, including cyanobacteria ( Anabaena variabilis), diatoms (Skeletonema costatum), phaeophytes (Asc ophyllum nodosum), in copepod molts, and in freshwater vascular aquati c plants (water hyacinths and duckweed). In unfavorable conditions V. cholerae assumes spore-like forms; with proper nutrients, pH and tempe rature, it reverts to a readily transmissible and infectious state. Ni trates and phosphates in sewage and fertilizers cause eutrophication, and scientists report an increase in intensity, duration and shifts in the biodiversity of algal blooms in many coastal, brackish and fresh waters worldwide. V. cholerae has been isolated from phyto- and zoopla nkton in marine and fresh waters near Lima, Peru. V. cholerae 01, biot ype El Tor, serotype Inaba, may have arrived in the Americas in the bi lge of a Chinese freighter. There, in the abundant coastal sea life al ong the Latin American Pacific coast, nourished by the Humboldt curren t and eutrophication, it found a reservoir for surviving unfavorable c onditions. It is hypothesized that the algae and Vibrio populations gr ew exponentially; consumed by fish, mollusks and crustacea, a heavy 'i noculum' of carriers infected with V. cholerae was generated and trans ported into multiple coastal communities.