Risk of sexual transmission of Zika virus infection: a study among sex workers and their clients in an endemic area of coastal Ecuador

寨卡病毒（ZIKV）是一种通过伊蚊叮咬传播给人类的黄病毒，最近于2015年在美洲流行。目前没有ZIKV的疫苗或治疗方法。大约80%的ZIKV感染者无症状，有症状的病例显示轻度发热。然而，在拉丁美洲疫情持续期间，同时报告的严重神经系统并发症和受感染孕妇的不良胎儿结局令人关切。ZIKV现在被认为与新生儿小头畸形症有因果关系，其辅助因素未知，这可能是拉丁美洲发病率区域差异的原因。除了经典传播外，ZIKV显然会追随埃博拉病毒的脚步。病毒在感染后的精液和外阴阴道液中持续存在，在缺乏经典蚊子传播途径的情况下，越来越多的病例报告显示人类之间的性传播。如果性传播被证明是一种既定的传播途径，那么在有传播媒介的地区，单靠蚊虫控制可能不足以遏制ZIKV从零星流行向持续流行的转变。该项目将首先确定厄瓜多尔埃斯梅拉达斯省Quininde地区的基线血清阳性率。女性性工作者将被招募，并进行ZIKV和该地区其他蚊媒流行病毒的血清学筛查。来自性工作者人群的样本将与在Quininde公立医院接受产前检查的育龄妇女的年龄和性别匹配的对照组进行比较，以确定在那些具有“高”风险性行为的人群中是否有更高的ZIKV患病率，以估计性传播对ZIKV总体负担的可能影响。还将向参与者发放一份问卷，收集有关人口、社会经济和生活方式的信息（包括敏感性行为和其他高风险行为，如坚持使用避孕套、生殖器外性行为和非法药物使用）。2本博士项目涉及医学研究理事会提出的所有四个战略目标的各个方面（MRC，Research Changes Lives，MRC Strategic Plan 2014- 2019 https：//www.mrc.ac.uk/publications/browse/strategic-plan-2014-19/）.Strategic Aim 1：Research that Delivers; Theme Two“Living a Long and Healthy Life”AND Strategic Aim 2：评估性传播的风险因素，随后为高危群体的目标教育/筛查提供信息，以及加强围绕ZIKV的公共卫生意识工作。战略目标3：走向全球通过与厄瓜多尔的合作实验室合作，我们的项目不仅促进了伦敦圣乔治大学、MRC LID项目和国际大学之间的合作，该项目的研究结果有可能支持在一个节育和避孕套尚未广泛提供或使用的国家倡导女性和性工作者的性健康和权利。支持科学家，能力和技能学生将接受以下方面的培训;定量技能流行病学问卷的创建和分析分子，基因组和系统发育技术跨学科技能与社会和定性科学家合作，制定问卷和道德/与实验室科学家合作开发分子和组学技能与厄瓜多尔当地环境合作开发领域流行病学和西班牙语医学全生物体生理学了解患者体内ZIKV感染动力学ZIKV基因组分析，以了解ZIKV的症状和生物学表现

Zika Virus (ZIKV) is a flavivirus transmitted to humans through the bite of Aedes mosquitoes, recentlyepidemic in the Americas in 2015. There is currently no vaccine or treatment for ZIKV. ZIKV isasymptomatic in approximately 80% of those infected, with symptomatic cases displaying mild febrileillness. However, during the ongoing Latin America epidemic, concurrent reporting of severeneurologic complications and adverse foetal outcomes in infected pregnant women became cause forconcern. ZIKV is now considered causally linked to microcephaly in new-borns with unknown cofactorsperhaps accounting for regional variation in incidence in Latin America.In addition to classic transmission, it has become apparent that ZIKV follows in the footsteps of Ebola.Virus is persistent in semen and vulvovaginal fluids post-infection, with increasing numbers of casereports of sexual transmission between humans in the absence of classical mosquito transmissionpathways. If sexual transmission proves to be an established transmission route, mosquito controlefforts alone may not be enough to curb the transition of ZIKV from sporadic epidemic to sustainedendemicity in regions with capable vectors.The project will initially determine the baseline seroprevalence of ZIKV in the District of Quininde,Esmeraldas Province, Ecuador among high-risk groups for STIs. Female sex workers will be recruitedand serologically screened for ZIKV, and other mosquito borne viruses endemic to the region. Samplesfrom sex worker populations will be compared to those of an age and gender-matched control group ofwomen of childbearing age attending antenatal clinics at the public hospital in Quininde, to determine ifthere is a higher prevalence of ZIKV in those with 'high' risk sexual behaviours to estimate the possiblecontribution of sexual transmission to overall ZIKV burden. Participants will also be administered aquestionnaire collecting information on relevant demographic, socioeconomic and lifestyle information(including sensitive sexual and other high risk behaviours such as consistency of condom use, extragenitalsex and illicit drug use). 2This PhD project addresses aspects of all four Strategic Aims laid out by the Medical Research Council(MRC, Research Changes Lives, MRC Strategic Plan 2014-2019https://www.mrc.ac.uk/publications/browse/strategic-plan-2014-19/).Strategic Aim 1: Research that Delivers; Theme Two "Living a Long and Healthy Life" ANDStrategic Aim 2: Research to the peopleAssessment of risk factors for sexual transmission, subsequently informing targetededucation/screening of high-risk groups, as well as enhancing public health awareness effortssurrounding ZIKV.Strategic Aim 3: Going GlobalBy working within partner laboratories in Ecuador, our project not only fosters collaborationbetween St George's University London, the MRC LID programme and the InternationalUniversity (of Ecuador), but also builds capacity within Ecuador.The findings of this project have the potential to support advocacy for female and sex workersexual health and rights in a country, where birth control and condoms are not widely availableor used.Strategic Aim 4: Supporting Scientists, Capacity and SkillsThe student will undergo training in the following areas;Quantitative SkillsEpidemiological questionnaire creation and analysisMolecular, genomic and phylogenetic techniquesInterdisciplinary SkillsCollaboration with social and qualitative scientists to develop questionnaires andethically/socially robust project protocolsWorking with laboratory scientists to develop molecular and 'omic skillsWorking with local settings in Ecuador to develop field epidemiology and Spanish languageskillsWhole Organism PhysiologyDeveloping an understanding of ZIKV infection kinetics within patientsZIKV genomic analysis to understand symptomatic and biological presentation of ZIKV