Uganda Public Health Fellowship Program, P.O. Box 7272, Kampala, Uganda.
Ministry of Health of Uganda, Kampala, Uganda.
BMC Infect Dis. 2018 Nov 3;18(1):548. doi: 10.1186/s12879-018-3440-y.
On 28 March, 2016, the Ministry of Health received a report on three deaths from an unknown disease characterized by fever, jaundice, and hemorrhage which occurred within a one-month period in the same family in central Uganda. We started an investigation to determine its nature and scope, identify risk factors, and to recommend eventually control measures for future prevention.
We defined a probable case as onset of unexplained fever plus ≥1 of the following unexplained symptoms: jaundice, unexplained bleeding, or liver function abnormalities. A confirmed case was a probable case with IgM or PCR positivity for yellow fever. We reviewed medical records and conducted active community case-finding. In a case-control study, we compared risk factors between case-patients and asymptomatic control-persons, frequency-matched by age, sex, and village. We used multivariate conditional logistic regression to evaluate risk factors. We also conducted entomological studies and environmental assessments.
From February to May, we identified 42 case-persons (35 probable and seven confirmed), of whom 14 (33%) died. The attack rate (AR) was 2.6/100,000 for all affected districts, and highest in Masaka District (AR = 6.0/100,000). Men (AR = 4.0/100,000) were more affected than women (AR = 1.1/100,000) (p = 0.00016). Persons aged 30-39 years (AR = 14/100,000) were the most affected. Only 32 case-patients and 128 controls were used in the case control study. Twenty three case-persons (72%) and 32 control-persons (25%) farmed in swampy areas (OR = 7.5; 95%CI = 2.3-24); 20 case-patients (63%) and 32 control-persons (25%) who farmed reported presence of monkeys in agriculture fields (OR = 3.1, 95%CI = 1.1-8.6); and 20 case-patients (63%) and 35 control-persons (27%) farmed in forest areas (OR = 3.2; 95%CI = 0.93-11). No study participants reported yellow fever vaccination. Sylvatic monkeys and Aedes mosquitoes were identified in the nearby forest areas.
This yellow fever outbreak was likely sylvatic and transmitted to a susceptible population probably by mosquito bites during farming in forest and swampy areas. A reactive vaccination campaign was conducted in the affected districts after the outbreak. We recommended introduction of yellow fever vaccine into the routine Uganda National Expanded Program on Immunization and enhanced yellow fever surveillance.
2016 年 3 月 28 日，卫生部收到报告，乌干达中部同一家庭在一个月内发生三例不明原因疾病死亡，这些疾病的特征为发热、黄疸和出血。我们开始进行调查，以确定其性质和范围，确定危险因素，并为今后的预防提出控制措施。
我们将不明原因发热伴以下 1 种或多种不明原因症状定义为疑似病例：黄疸、不明原因出血或肝功能异常。确诊病例为黄热病 IgM 或 PCR 阳性的疑似病例。我们查阅了病历并开展了社区主动病例搜索。在病例对照研究中，我们比较了病例患者和无症状对照者的危险因素，按年龄、性别和村庄进行频数匹配。我们使用多变量条件逻辑回归来评估危险因素。我们还进行了昆虫学研究和环境评估。
从 2 月到 5 月，我们共发现 42 例病例（35 例疑似病例和 7 例确诊病例），其中 14 例（33%）死亡。所有受影响地区的总发病率（AR）为 2.6/100000，马萨卡区（AR=6.0/100000）最高。男性（AR=4.0/100000）比女性（AR=1.1/100000）更易受影响（p=0.00016）。30-39 岁人群（AR=14/100000）受影响最严重。只有 32 例病例患者和 128 例对照者用于病例对照研究。23 例病例患者（72%）和 32 例对照者（25%）在沼泽地区务农（OR=7.5；95%CI=2.3-24）；20 例病例患者（63%）和 32 例对照者（25%）报告说在农业用地中有猴子（OR=3.1，95%CI=1.1-8.6）；20 例病例患者（63%）和 35 例对照者（27%）在森林地区务农（OR=3.2；95%CI=0.93-11）。没有研究参与者报告接种过黄热病疫苗。在附近的森林地区发现了野生猴子和埃及伊蚊。
此次黄热病暴发可能是丛林型的，通过在森林和沼泽地区务农时蚊子叮咬，传播给易感人群。疫情发生后，在受影响地区开展了反应性疫苗接种活动。我们建议将黄热病疫苗纳入乌干达国家扩大免疫规划常规疫苗，并加强黄热病监测。
