International Outbreak Investigations
International outbreak investigations involve providing assistance to foreign Ministries of Health to identify the causes, understand the associated risk factors, control transmission, and prevent further spread of water, sanitation, and hygiene (WASH)-related disease. Providing this international assistance is a critical service provided by CDC’s WASH experts.
CDC responds to international, WASH-related outbreaks by working collaboratively with various CDC experts, U.S. and foreign government agencies, Ministries of Health, health professionals, non-governmental organizations (NGOs), and U.N. organizations. CDC has expertise across the agency, which includes epidemiologic, laboratory, environmental health, engineering, and behavioral scientists.
Investigating Typhoid Fever in Zimbabwe
In November 2011, a team from CDC-Atlanta, CDC-Kenya/Kenya Medical Research Institute, and the South Africa Field Epidemiology and Laboratory Training Program was invited to assist the Zimbabwe Ministry of Health and Child Welfare and City of Harare City Health Department with an investigation of a suspected outbreak of typhoid fever in Harare, Zimbabwe.
As of May 2, 2012, a total of 4,185 suspected cases of typhoid fever had been identified in Harare; 52 cases were confirmed by blood or stool culture. Median age was 15 years (range: <1-95 years); 54% were female. Hospitalization was reported for 1,788 patients (43%), and two deaths were reported.
Samples from two of six boreholes and all seven shallow wells sampled yielded Escherichia coli (an indicator for fecal contamination); all municipal taps tested negative for E. coli. While this descriptive study does not prove illness was associated with contaminated water, it seems likely. Rural-to-urban migration has resulted in overcrowding in residential areas and has outpaced maintenance and expansion of water supply and sewerage infrastructure. Rationing of piped, treated water from municipal systems obliges residents to use unimproved water sources to meet their water needs, putting them at risk for gastrointestinal infections. Frequent sewer blockages compound this problem.
Recommendations included promotion of household chlorination of drinking water from all sources. Longer-term efforts are currently underway to upgrade infrastructure by replacing old cast-iron pipes with new polyvinyl chloride pipes, remediate existing borehole wells and drill new ones, and establish local reservoir tanks. This outbreak and other recent evidence of the magnitude of epidemic and endemic typhoid fever in sub-Saharan African countries highlights the continued importance of typhoid fever prevention and control in Africa.
- Read Notes from the Field: Salmonella Typhi Infections Associated with Contaminated Water in Zimbabwe in the Morbidity and Mortality Weekly Report (MMWR).
Cholera in Haiti: One Year Later
On October 19, 2010, ten months after the catastrophic January 2010 earthquake in Haiti that killed over 200,000 people and displaced over 1 million, the Haitian Ministry of Public Health and Population (MSPP) was notified of a sudden increase in patients presenting with watery diarrhea and dehydration in the Artibonite and Centre Departments. On October 21, 2010, the Haiti National Public Health Laboratory identified the pathogen as Vibrio cholerae. One day later, the first cholera outbreak in Haiti in at least a century was officially announced.