Emerg Infect Dis. 2020 Jul;26(7):1364-1373. doi: 10.3201/eid2607.190846.
After a chikungunya outbreak in Salvador, Brazil, we performed a cross-sectional, community-based study of 1,776 inhabitants to determine chikungunya virus (CHIKV) seroprevalence, identify factors associated with exposure, and estimate the symptomatic infection rate. From November 2016 through February 2017, we collected sociodemographic and clinical data by interview and tested serum samples for CHIKV IgG. CHIKV seroprevalence was 11.8% (95% CI 9.8%-13.7%), and 15.3% of seropositive persons reported an episode of fever and arthralgia. Infections were independently and positively associated with residences served by unpaved streets, a presumptive clinical diagnosis of chikungunya, and recall of an episode of fever with arthralgia in 2015-2016. Our findings indicate that the chikungunya outbreak in Salvador may not have conferred sufficient herd immunity to preclude epidemics in the near future. The unusually low frequency of symptomatic disease points to a need for further longitudinal studies to better investigate these findings.
巴西萨尔瓦多发生基孔肯雅热疫情后，我们开展了一项基于社区的横断面研究，共调查了 1776 名居民，以确定基孔肯雅病毒（CHIKV）血清流行率，确定与暴露相关的因素，并估计有症状感染率。2016 年 11 月至 2017 年 2 月，我们通过访谈收集社会人口学和临床数据，并检测血清样本中的 CHIKV IgG。CHIKV 血清流行率为 11.8%（95%CI9.8%-13.7%），15.3%的血清阳性者报告曾出现发热和关节痛。感染与居住在未铺砌街道的地方、疑似基孔肯雅热的临床诊断以及回忆 2015-2016 年曾有发热伴关节痛的经历呈独立正相关。我们的研究结果表明，萨尔瓦多的基孔肯雅热疫情可能没有提供足够的群体免疫力，无法防止近期的流行。异常低的有症状疾病发生率表明需要进一步开展纵向研究，以更好地调查这些发现。
