A Randomized, Double Blind, Controlled Study to Determine the Efficacy of Zinc Supplementation on Diarrhea Incidence in an Adult Population in Western Kenya.

Diarrhea has been a major cause of morbidity, hospitalization, and loss of duty days for military personnel for centuries. In fact, diarrheal illness is the most common medical problem for U.S. troops during operational deployment. Soldiers are especially prone to diarrhea because of travel, consumption of locally procured foods (including raw vegetables and poorly-cooked meat products) and the use of nonpotable water, or ice. High rates of occurrence continue to be reported in soldiers deployed to recent conflicts. Furthermore, high morbidity rates from enteric disease have been reported by other military forces in areas of current combat operations: up to 53%-69% of Soviet troops had major gastrointestinal infections during the Afghanistan war, and up to 69% of British troops and 36% of Australian troops reported diarrhea in Iraq during Operation Safe Haven in 1991.

The region of sub-Saharan Africa, where the proposed study would be conducted, is uniquely positioned for anti-diarrheal research that can offer answers to problems of the civilian population, displaced persons and deployed soldiers or workers in remote areas. Diarrheal disease is the 4th leading cause of out-patient morbidity in Kenya, accounting for almost 5% of all new outpatient cases, with a higher prevalence in Nyanza Province - 5.4% to 7.1% of total new cases. Kisumu lies in the Nyanza Province in western Kenya, bordering Lake Victoria and populated by the Luo ethnic group. Nyanza is one of Kenya's most impoverished provinces with one of the nation's lowest immunization rates, highest infant mortality and highest prevalence of HIV (35% among adults 15-49 years old in 2000, as compared to 14% nationally). Malnutrition is common; endemic diseases include malaria, leishmaniasis, tuberculosis and schistosomiasis.

Scientists from the Centers for Disease Control and Prevention (CDC) have reported on the species of bacterial pathogens isolated from diarrhea patients in the Kisumu area: the bacterial isolates were similar to those reported in U.S. soldiers (44% Shigella; 30% Campylobacter; 14% Salmonella). However, most of the isolates (51%) were not susceptible to their antimicrobial treatment. The study by Brooks et al. (2003), reported that more than 90% of the isolates (excluding Campylobacter) were resistant to trimethoprim-sulfamethoxazole and tetracycline, and more than 80% were resistant to ampicillin.

If this alarming trend persists, and drug-resistant bacteria are identified in civilian populations, gains in disease control strategies already deployed will not be achieved, and in case of deployed members of the military or workforce, mission-impact may be severely compromised. Thus, we propose that the Kombewa Clinical Research Center (KCRC), located outside of Kisumu, would allow for testing of a novel anti-diarrheal treatment, specifically dietary zinc (Zn), in antibiotic-resistant bacteria with potential benefits to not only the deployed U.S. military and western Kenyan populations, but also other populations in Africa. Populations living in the Kombewa area will serve as potential study volunteers because of the high prevalence of antibiotic-resistant diarrhea in adults in this region.

This study will build upon the proven concept that Zn-supplementation, as an adjunct to oral rehydration, is highly protective against diarrhea in children. The results are expected to provide the scientific basis and common pathway for development of a commercially viable, multivalent, food-based, anti-diarrheal supplement for vulnerable populations such as troops prior to deployment, deprived and displaced persons. Based on a successful outcome, we would expect to attract commercial support for a final micronutrient formulation suitable for field use and expanded efficacy evaluation in pivotal studies for support of licensure. An anti-diarrheal product for adults will fill an important military, refugee population need and have dual use in the civilian sector.