Environmental Survey of Drinking Water Sources in Kampala, Uganda, during a Typhoid Fever Outbreak
Environmental Survey of Drinking Water Sources in Kampala, Uganda, during a Typhoid Fever Outbreak
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DOI：
10.1128/aem.01706-17
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发表时间：
2017-12-01
影响因子：
4.4
通讯作者：
Hill, V. R.
中科院分区：
文献类型：
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作者：
Murphy, J. L.;Kahler, A. M.;Hill, V. R.
2015年，乌干达坎帕拉市中心开始爆发伤寒，并蔓延到邻近地区。作为回应，在该市病例数高的地区进行了饮用水水源类型的环境调查。从12种来源类型中共收集了122个样本，并进行了大肠杆菌、游离氯和电导率的检测。还收集了来自7种来源类型的另外37份抓取样本和来自威尔斯和泉水的16对大体积（20升）样本，并检测了伤寒沙门氏菌的存在。大肠杆菌在60%的kavera（塑料袋出售的饮用水）和80%的重新灌装的水瓶中被检测到;在两种来源类型中都没有检测到游离氯。大多数杰里罐（68%）含有E。大肠杆菌和游离氯残留低于世卫组织建议的水平0.5毫克/升在爆发。卡韦拉斯、重新灌装的水瓶和杰里罐（与自来水公司提供的处理过的地表水相比）的电导率读数升高，表明它们可能含有未经处理的地下水。所有未受保护的泉水和威尔斯井以及60%以上的受保护泉水均含有E.杆菌从自来水公司收集的水样被发现有可接受的游离氯水平，没有检测到大肠杆菌。杆菌而S.水样中未检出伤寒，沙门氏菌属。在两个未受保护的弹簧，一个受保护的弹簧和一个重新填充的水瓶的样本中检测到。这些数据提供了明确的证据表明，不受管制的出售水和地下水代表了伤寒传播的风险。重要性尽管全球伤寒的发病率很高，但相对较少的疫情调查包括饮用水检测。在水传播疾病爆发期间，测量物理化学参数，如游离余氯和电导率，以及微生物学参数，如大肠杆菌的存在。大肠杆菌或相关的病原体，在饮用水样品中可以确定污染源。这项调查表明，在2015年坎帕拉伤寒爆发期间，不受管制的销售水和地下水源受到污染，因此对消费者构成风险。查明受污染的饮用水水源和消毒剂含量不足的水源，可以迅速采取有针对性的干预措施。
In 2015, a typhoid fever outbreak began in downtown Kampala, Uganda, and spread into adjacent districts. In response, an environmental survey of drinking water source types was conducted in areas of the city with high case numbers. A total of 122 samples was collected from 12 source types and tested for Escherichia coli, free chlorine, and conductivity. An additional 37 grab samples from seven source types and 16 paired large volume (20 liter) samples from wells and springs were also collected and tested for the presence of Salmonella enterica serovar Typhi. Escherichia coli was detected in 60% of kaveras (drinking water sold in plastic bags) and 80% of refilled water bottles; free chlorine was not detected in either source type. Most jerry cans (68%) contained E. coli and had free chlorine residuals below the WHO-recommended level of 0.5 mg/liter during outbreaks. Elevated conductivity readings for kaveras, refilled water bottles, and jerry cans (compared to treated surface water supplied by the water utility) suggested that they likely contained untreated groundwater. All unprotected springs and wells and more than 60% of protected springs contained E. coli. Water samples collected from the water utility were found to have acceptable free chlorine levels and no detectable E. coli. While S. Typhi was not detected in water samples, Salmonella spp. were detected in samples from two unprotected springs, one protected spring, and one refilled water bottle. These data provided clear evidence that unregulated vended water and groundwater represented a risk for typhoid transmission.IMPORTANCE Despite the high incidence of typhoid fever globally, relatively few outbreak investigations incorporate drinking water testing. During waterborne disease outbreaks, measurement of physical-chemical parameters, such as free chlorine residual and electrical conductivity, and of microbiological parameters, such as the presence of E. coli or the implicated etiologic agent, in drinking water samples can identify contaminated sources. This investigation indicated that unregulated vended water and groundwater sources were contaminated and were therefore a risk to consumers during the 2015 typhoid fever outbreak in Kampala. Identification of contaminated drinking water sources and sources that do not contain adequate disinfectant levels can lead to rapid targeted interventions.