Uganda Public Health Fellowship Program, Kampala, Uganda.
Central Public Health Laboratories, Ministry of Health, Kampala, Uganda.
BMC Infect Dis. 2021 Dec 27;21(1):1281. doi: 10.1186/s12879-021-07011-9.
Kampala city slums, with one million dwellers living in poor sanitary conditions, frequently experience cholera outbreaks. On 6 January 2019, Rubaga Division notified the Uganda Ministry of Health of a suspected cholera outbreak in Sembule village. We investigated to identify the source and mode of transmission, and recommended evidence-based interventions.
We defined a suspected case as onset of profuse, painless, acute watery diarrhoea in a Kampala City resident (≥ 2 years) from 28 December 2018 to 11 February 2019. A confirmed case was a suspected case with Vibrio cholerae identified from the patient's stool specimen by culture. We found cases by record review and active community case-finding. We conducted a case-control study in Sembule village, the epi-center of this outbreak, to compare exposures between confirmed case-persons and asymptomatic controls, individually matched by age group. We overlaid rainfall data with the epidemic curve to identify temporal patterns between rain and illnesses. We conducted an environmental assessment, interviewed village local council members, and tested water samples from randomly-selected households and water sources using culture and PCR to identify V. cholerae.
We identified 50 suspected case-patients, with three deaths (case-fatality rate: 6.0%). Of 45 case-patients with stool samples tested, 22 were confirmed positive for V. cholerae O1, serotype Ogawa. All age groups were affected; persons aged 5-14 years had the highest attack rate (AR) (8.2/100,000). The epidemic curve showed several point-source outbreaks; cases repeatedly spiked immediately following rainfall. Sembule village had a token-operated water tap, which had broken down 1 month before the outbreak, forcing residents to obtain water from one of three wells (Wells A, B, C) or a public tap. Environmental assessment showed that residents emptied their feces into a drainage channel connected to Well C. Drinking water from Well C was associated with illness (OR = 21, 95% CI 4.6-93). Drinking water from a public tap (OR = 0.07, 95% CI 0.014-0.304) was protective. Water from a container in one of eight households sampled tested positive for V. cholerae; water from Well C had coliform counts ˃ 900/100 ml.
Drinking contaminated water from an unprotected well was associated with this cholera outbreak. We recommended emergency chlorination of drinking water, fixing the broken token tap, and closure of Well C.
坎帕拉市贫民窟有 100 万居民生活在卫生条件差的环境中，经常爆发霍乱。2019 年 1 月 6 日，Rubaga 分区向乌干达卫生部报告称，Sembule 村发生疑似霍乱疫情。我们进行了调查以确定疫情的源头和传播方式，并提出了基于证据的干预措施。
我们将 2018 年 12 月 28 日至 2019 年 2 月 11 日期间，在坎帕拉市居住的（年龄≥2 岁）出现剧烈、无痛、急性水样腹泻的患者定义为疑似病例。确诊病例是指从患者粪便标本中通过培养鉴定出霍乱弧菌的疑似病例。我们通过病历回顾和主动社区病例发现来发现病例。我们在疫情中心 Sembule 村开展了一项病例对照研究，以比较确诊病例和无症状对照者之间的暴露情况，病例和对照按照年龄组进行个体匹配。我们将降雨量数据与疫情曲线叠加，以确定降雨与疾病之间的时间模式。我们还开展了环境评估，访谈了村议会成员，并对随机选择的家庭和水源的水样进行了文化和 PCR 检测，以鉴定霍乱弧菌。
我们共发现了 50 例疑似病例，其中 3 人死亡（病死率：6.0%）。对 45 例有粪便样本的病例进行检测，有 22 例霍乱弧菌 O1 血清型 Ogawa 呈阳性。所有年龄组均受到影响；5-14 岁人群的发病率（AR）最高（8.2/100,000）。疫情曲线显示有几次集中爆发；降雨后病例数立即激增。Sembule 村有一个投币式水龙头，在疫情爆发前一个月就坏了，迫使居民从三个水井（水井 A、B、C）或一个公共水龙头获取水。环境评估显示，居民将粪便排入与水井 C 相连的排水渠。饮用水井 C 的水与发病有关（OR=21，95%CI 4.6-93）。饮用公共水龙头的水（OR=0.07，95%CI 0.014-0.304）具有保护作用。从抽样的 8 户家庭中的一户的容器中检测到的饮用水呈霍乱弧菌阳性；水井 C 的大肠菌群数超过 900/100ml。
饮用未受保护水井的污染水与此次霍乱疫情有关。我们建议对饮用水进行紧急氯化处理，修复损坏的投币式水龙头，并关闭水井 C。
