52 CONTROL OF WATERBORNE PATHOGENS IN DEVELOPING COUNTRIES

Cholera epidemics are known to have strong ties to changes in climatic conditions, and it has been suggested that cholera outbreaks can be predicted by monitoring changes in season, sea surface temperature, water temperature, water depth, rainfall, conduc- tivity, pH, sunlight, and the abundance of phytoplankton, zooplankton, and copepods (summarized by Huq et al., 2005). Predictive cholera models are still in the develop- mental phase (WHO, 2004). An early warning system will need to include pathogen, host, and environmental components (Koelle et al., 2005). The ecological parameters of environmental change that influence the evolution and transmission of pathogens are still poorly understood (Sack et al., 2003). Knowing when an outbreak is likely to occur can inform public health workers to stress basic hygiene and sanitation and to implement simple mitigation efforts such as Sari cloth filtration, which in some areas is credited with reducing cholera mortality by more than 50% (Colwell et al., 2003).

2.7 CONCLUDING THOUGHTS

Most waterborne disease is preventable given basic hygiene and sanitation, but these two factors are critical and possible only through education. Over the past two decades, the mantra of the international agencies has become “education and empowerment of women.” Although critical, it is not enough. Many developing countries are primarily male-dominated at the government level, and it is governments that decide resource allocations— new government offices or a new waste treatment plant? Governments are also responsible for aid distribution and for accelerating international conflict. No human behavior exacerbates infectious diseases more than international conflict. The inevitable refugee populations and destruction of infrastructure create enormous opportunities for disease transmission (Mbabazi et al., 2006), and the psychological stressors that must inevitably increase population susceptibility to all disease (Glaser et al., 1999).

Can we control waterborne disease in developing countries? From the Asian tsunami event, it is clearly possible, but a strong political will is necessary, as is cooperation between people and governments. For this to happen, education of politicians, and particularly people in power, becomes pivotal and will involve a dramatic cultural shift for most societies. The potential gains in global health are, however, significant. Pr¨uss- ¨Ust¨un et al. (2008) suggest that about 10% of the “global burden of infectious disease could be prevented by improving water supply, sanitation, hygiene and man- agement of water resources.” The authors suggest the percentage may be higher if we could include such currently unquantifiable diseases as legionellosis, leptospirosis, and others. In addition, the contribution of waterborne disease to morbidity and mortality from diseases such as HIV and malaria is as yet unknown, but is likely to be high.

REFERENCES

Albert, M.J., Faruque, A.S.G., Faruque, S.M., Sack, R.B., and Mahalanabis, D. (1999) Case– control study of enteropathogens associated with childhood diarrhea in Dhaka, Bangladesh. J. Clin. Microbiol., 37, 3458 –3464.

Barry, M. (2007) The tail end of guinea worm: global eradication without a drug or a vaccine. N. Engl. J. Med., 356, 2561 –2564.

REFERENCES 53

Baumgartner, J., Murcott, S., and Ezzati, M. (2007) Reconsidering ‘appropriate technology’: the effects of operating conditions on the bacterial removal performance of two household drinking-water filter systems. Environ. Res. Lett., 2, 024003.

Bielaszewska, M., Prager, R., K¨ock, R., et al. (2007) Shiga toxin gene loss and transfer in vitro and in vivo during enterohemorrhagic Escherichia coli O26 infection in humans. Appl. Environ. Microbiol., 73, 3144 –3150.

Brennan, R.J., and Rimba, K. (2005) Rapid health assessment in Aceh Jaya District, Indonesia, following the December 26 tsunami. Emerg. Med. Australasia, 17, 341 –350.

Carter Center (2008) http://www.cartercenter.org/health/guinea_worm/index.html (accessed July 2008).

CAWST (Centre for Affordable Water and Sanitation Technology) (2008a) www.cawst.org (accessed July 25, 2008).

CAWST (2008b) Summary of field and laboratory testing for the biosand filter.

http://www.cawst.org/assets/File/BSF_Literature_Brief.pdf (accessed July 2008).

Centers for Disease Control (CDC) (2007) Malaria facts. http://www.cdc.gov/malaria/facts.htm (accessed July 2008).

Centers for Disease Control (CDC) (2008a) Rotavirus. http://www.cdc.gov/rotavirus/ (accessed July 2008).

Centers for Disease Control (CDC) (2008b) Melioidosis. http://www.cdc.gov/nczved/dfbmd/ disease_listing/melioidosis_gi.html (accessed July 2008).

Centers for Disease Control (CDC) (2008c) Safe water system. http://www.cdc.gov/safewater/ (accessed July 2008).

Chapin, A.R., Carpenter, C.M., Dudley, W.C., et al. (2005) Prevalence of norovirus among visitors from the United States to Mexico and Guatemala who experience traveler’s diarrhea. J. Clin. Microbiol., 43, 1112 –1117.

Cheng, A.C., and Currie, B.J. (2005) Melioidosis: epidemiology, pathophysiology, and manage- ment. Clin. Microbiol. Rev., 18, 383 –416.

Clasen, T., Parra, G.G., Boisson, S., and Collin, S. (2005) Household-based ceramic water filters for the prevention of diarrhea: a randomized, controlled trial of a pilot program in Colombia. Am. J. Trop. Med. Hyg., 73, 790 –795.

Colwell, R.R. (1996) Global climate and infectious disease: the cholera paradigm. Science, 274, 2025 –2031.

Colwell, R.R., Huq, A., Islam, M.S., et al. (2003) Reduction of cholera in Bangladeshi villages by simple filtration. Proc. Natl. Acad. Sci. U.S.A., 100, 1051 –1055.

Donnenberg, M.S., and Whittam, T.S. (2001) Pathogenesis and evolution of virulence in enteropathogenic and enterohemorrhagic Escherichia coli . J. Clin. Invest., 107, 539 –548. Faruque, S.M., Albert, M.J., and Mekalanos, J.J. (1998) Epidemiology, genetics, and ecology

of toxigenic Vibrio cholerae. Microbiol. Mol. Biol. Rev., 62, 1301 –1314.

Faruque, S.M., Biswas, K., Udden, S.M.N., et al. (2006) Transmissibility of cholera: in vivo –formed biofilms and their relationship to infectivity and persistence in the environment. Proc. Natl. Acad. Sci. U.S.A., 103, 6350 –6355.

Feng, P. (1995) Escherichia coli serotype O157:H7: novel vehicles of infection and emergence of phenotypic variants. Emerg. Infect. Dis., 1, 47 –52.

Fenwick, A. (2006) Waterborne infectious diseases: Could they be consigned to history? Science, 313, 1077 –1081.

Ford, T.E. (1999) Microbiological safety of drinking water: United States and global perspec- tives. Environ. Health Perspect., 107(Suppl. 1), 191 –206.

Ford, T.E. (2004) Future needs and priorities. In Cloete, T.E., Rose, J., Nel, L.H., and Ford, T. (eds.), Microbial Waterborne Pathogens. IWA Publishing, London, pp. 187 –204.