Teixeira Maria Glória, Skalinski Lacita Menezes, Paixão Enny S, Costa Maria da Conceição N, Barreto Florisneide Rodrigues, Campos Gubio Soares, Sardi Silvia Ines, Carvalho Rejane Hughes, Natividade Marcio, Itaparica Martha, Dias Juarez Pereira, Trindade Soraya Castro, Teixeira Bárbara Pereira, Morato Vanessa, Santana Eloisa Bahia, Goes Cristina Borges, Silva Neuza Santos de Jesus, Santos Carlos Antonio de Souza Teles, Rodrigues Laura C, Whitworth Jimmy
Instituto de Saúde Coletiva/ Universidade Federal da Bahia, Salvador-BA, Brazil.
Departamento de Ciências da Saúde/ Universidade Estadual de Santa Cruz, Ilhéus-BA, Brazil.
PLoS Negl Trop Dis. 2021 Apr 20;15(4):e0009289. doi: 10.1371/journal.pntd.0009289. eCollection 2021 Apr.
Chikungunya is an arbovirus, transmitted by Aedes mosquitoes, which emerged in the Americas in 2013 and spread rapidly to almost every country on this continent. In Brazil, where the first cases were detected in 2014, it currently has reached all regions of this country and more than 900,000 cases were reported. The clinical spectrum of chikungunya ranges from an acute self-limiting form to disabling chronic forms. The purpose of this study was to estimate the seroprevalence of chikungunya infection in a large Brazilian city and investigate the association between viral circulation and living condition.
METHODOLOGY/PRINCIPAL FINDINGS: We conducted a population-based ecological study in selected Sentinel Areas (SA) through household interviews and a serologic survey in 2016/2017. The sample was of 1,981 individuals randomly selected. The CHIKV seroprevalence was 22.1% (17.1 IgG, 2.3 IgM, and 1.4 IgG and IgM) and varied between SA from 2.0% to 70.5%. The seroprevalence was significantly lower in SA with high living conditions compared to SA with low living condition. There was a positive association between CHIKV seroprevalence and population density (r = 0.2389; p = 0.02033).
CONCLUSIONS/SIGNIFICANCE: The seroprevalence in this city was 2.6 times lower than the 57% observed in a study conducted in the epicentre of the CHIKV epidemic of this same urban centre. So, the herd immunity in this general population, after four years of circulation of this agent is relatively low. It indicates that CHIKV transmission may persist in that city, either in endemic form or in the form of a new epidemic, because the vector infestation is persistent. Besides, the significantly lower seroprevalences in SA of higher Living Condition suggest that beyond the surveillance of the disease, vector control and specific actions of basic sanitation, the reduction of the incidence of this infection also depends on the improvement of the general living conditions of the population.
基孔肯雅热是一种虫媒病毒，由伊蚊传播，于2013年在美洲出现并迅速蔓延至该大陆几乎每个国家。在巴西，2014年首次检测到病例，目前已波及该国所有地区，报告病例超过90万例。基孔肯雅热的临床谱范围从急性自限性形式到致残性慢性形式。本研究的目的是估计巴西一个大城市基孔肯雅热感染的血清流行率，并调查病毒传播与生活条件之间的关联。
方法/主要发现：我们于2016/2017年在选定的哨点地区（SA）通过家庭访谈和血清学调查进行了一项基于人群的生态学研究。样本为随机选取的1981名个体。基孔肯雅病毒（CHIKV）血清流行率为22.1%（IgG为17.1%，IgM为2.3%，IgG和IgM为1.4%），在各哨点地区之间从2.0%至70.5%不等。与生活条件低的哨点地区相比，生活条件高的哨点地区血清流行率显著更低。CHIKV血清流行率与人口密度之间存在正相关（r = 0.2389；p = 0.02033）。
结论/意义：该城市的血清流行率比在同一城市中心基孔肯雅热疫情中心进行的一项研究中观察到的57%低2.6倍。因此，在该病原体传播四年后，该总体人群中的群体免疫力相对较低。这表明基孔肯雅病毒传播可能在该城市持续存在，要么以地方病形式，要么以新的疫情形式，因为病媒滋生持续存在。此外，生活条件较高的哨点地区血清流行率显著更低，这表明除了疾病监测、病媒控制和基本卫生设施的具体行动外，降低这种感染的发病率还取决于改善人群的总体生活条件。
