A Centre for Diseases Control (CDC) investigative team, which tested water in Dzivaresekwa, a suburb of Harare, Zimbabwe during the typhoid outbreak, have found some public water facilities have fecal contamination.
According to the recent Morbidity and Mortality report from CDC, of the six public boreholes, seven shallow wells, and three municipal taps tested, two boreholes and all seven shallow wells yielded Escherichia coli, an indicator of fecal contamination. All municipal taps tested negative for E. coli.
Recommendations put forward by the team include the promotion of household chlorination of water from all sources as the chlorination of the municipal system may be unreliable.
It is also recommended that enough water purification tablets to treat 20-litres of drinking water per household every day for 3 months be distributed. The dissemination of messages highlighting the importance of safe water collection, treatment and storage, safe food preparation, and improved hygiene and sanitation practices was also recommended.
“Efforts are under way to upgrade infrastructure (replacing old cast-iron pipes with new polyvinyl chloride pipes to prevent breakages), remediate existing boreholes by shock chlorination and drilling new ones and establish local reservoir tanks,” the team notes in the report.
lt is also reported that although the descriptive study does not prove that illness was associated with contaminated water, the association seems likely.
The report finds that 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 enteric infections. Frequent sewer blockages compound this problem by further contaminating shallow wells used by residents for drinking water,” the report notes.
Each year, Salmonella Typhi causes an estimated 22 million cases of typhoid fever and 216,000 deaths worldwide. Humans are the only reservoir for S. Typhi, and infection occurs by the fecal-oral route, usually through ingestion of contaminated food or water.
An estimated 884 million people worldwide lack access to safe water, and nearly 2.5 billion persons do not have access to adequate sanitation. Incidence is highest in developing countries particularly in areas with poor sanitation or without access to safe water. 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.
On October 25 2011, a cluster of approximately 20 suspected cases of typhoid fever in residents of Dzivaresekwa was reported to the Harare’s health department.
On November 22, 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 with the investigation by providing epidemiologic and microbiologic support to better describe the outbreak and to evaluate response efforts.
As of May 2 this year, a total of 4,185 suspected cases of typhoid fever had been identified in Harare. Suspected cases were defined as fever of more than 3 days duration plus malaise, headache, vomiting, diarrhoea, constipation or cough in a person who had been in Harare since October 1, 2011.
A total of 52 confirmed cases met the suspected case definition and were confirmed by blood or stool culture. Median age of patients was 15 years; 54% were female. Hospitalization was reported for 1,788 patients (43%); two deaths were reported.
Suspected cases were reported predominantly in the high-density suburbs of Kuwadzana (1,957), Dzivaresekwa (1,012), and Marlborough (115). Of patients treated in Harare, 207 reported home addresses in other Zimbabwean provinces.
Suspected cases of typhoid fever in Harare continue to decline as of May 2, 2012. However, with limited surveillance systems and laboratory capacity, national trends are unclear.
