PNAS-2003-Colwell-1051-5

PNAS-2003-Colwell-1051-5 - Reduction of cholera in...

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Reduction of cholera in Bangladeshi villages by simple filtration Rita R. Colwell* †‡ , Anwar Huq* , M. Sirajul Islam § , K. M. A. Aziz § , M. Yunus § , N. Huda Khan § , A. Mahmud § , R. Bradley Sack , G. B. Nair § , J. Chakraborty § , David A. Sack § , and E. Russek-Cohen ± *Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD 21202; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742; § International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh; Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205; and ± Biometrics Program, Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742 Contributed by Rita R. Colwell, December 5, 2002 Based on results of ecological studies demonstrating that Vibrio cholerae , the etiological agent of epidemic cholera, is commensal to zooplankton, notably copepods, a simple Fltration procedure was developed whereby zooplankton, most phytoplankton, and particulates > 20 ± m were removed from water before use. Effec- tive deployment of this Fltration procedure, from September 1999 through July 2002 in 65 villages of rural Bangladesh, of which the total population for the entire study comprised ± 133,000 individ- uals, yielded a 48% reduction in cholera ( P < 0.005) compared with the control. C holera is a disease that continues to ravage developing countries and reemerges sporadically elsewhere throughout the world. According to the World Health Organization (WHO), 58 countries have officially reported cholera in 2001, with a total of 184,311 cases and 2,728 deaths (1). However, there were 293,113 cases of cholera worldwide in 1998, with 10,586 deaths. These annual figures of WHO actually represent the tip of the iceberg, because the morbidity and mortality caused by Vibrio cholerae is grossly underreported owing to surveillance difficul- ties and also for fear of economic and social consequences (2). In fact, several cholera endemic countries, e.g., Bangladesh, are not included in the WHO report. In 1991, after almost 100 years without cholera, outbreaks in 16 Latin American countries resulted in ± 400,000 reported cases of cholera and ² 4,000 reported deaths (3). That cholera is a waterborne disease has long been known (4–6). Furthermore, surface water has been linked with trans- mission of cholera since the pioneering work of Snow in 1854 (7). Demonstration of the potential for water to transmit cholera was provided by Koch, who, after Pacini first described the Vibrio (8), isolated and characterized the bacterium, which he named Vibrio comma , and was able to find it in pond water used by an Indian community suffering a cholera epidemic (9). The association of pathogenic vibrios with zooplankton was reported in 1973 by Kaneko and Colwell (10) and of V. cholerae with copepods by Huq et al. in 1983 (11). Commensal occurrence of Vibrio spp. in the copepod gut was demonstrated by Sochard et al. in 1979 (12). A few years later, preferential attachment of V. cholerae to copepod surfaces, egg cases, and the copepod oral region was reported by Huq et al.
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This note was uploaded on 07/07/2010 for the course BSCU 425 taught by Professor Rollins during the Fall '10 term at Maryland.

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PNAS-2003-Colwell-1051-5 - Reduction of cholera in...

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