School-Based Countrywide Seroprevalence Survey Reveals Spatial Heterogeneity in Malaria Transmission in the Gambia
School-Based Countrywide Seroprevalence Survey Reveals Spatial Heterogeneity in Malaria Transmission in the Gambia
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DOI：
10.1371/journal.pone.0110926
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发表时间：
2014-10-22
期刊：
影响因子：
3.7
通讯作者：
D'Alessandro, Umberto
中科院分区：
文献类型：
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作者：
Okebe, Joseph;Affara, Muna;D'Alessandro, Umberto
背景：随着疟疾传播的地理分布逐渐聚集化，确定剩余的传播区段对于研究和定向干预非常重要。以疟疾抗体为基础的监测日益被认为是对传统方法的宝贵补充，用于检测感染源，特别是在低传播水平。这项研究提供了在干燥、非传播季节测量的冈比亚学龄儿童传播异质性的血清学证据。方法：从全国30所学校随机选择健康小学生，进行疟疾感染(显微镜)和抗疟疾抗体(MSP119)筛查。抗体分布用两组分有限混合模型模拟，以第一组分平均值的2标准差为阳性截止点。结果：共调查4140名儿童，其中男孩1897名(46%)，平均年龄10.2岁(SD 2.6，范围4-20岁)。3640例(87.9%)儿童镜检结果显示，1.9%(69)儿童恶性疟原虫感染阳性，其中大多数(97.1%，67/69)无症状。总的血清阳性率为12.7%(527/4140)，学校的血清阳性率为0.6%~43.8%。年龄(OR 1.12，95%CI 1.07~1.16)和寄生虫携带者(OR 3.36，95%CI 1.95~5.79)与血清阳性密切相关。结论：对疟疾寄生虫的血清学反应可以识别已感染或已感染的个体，以及残留传播群。能够指导大规模筛查和治疗活动的现场适应抗体测试将非常有用。
Background: As the geographical distribution of malaria transmission becomes progressively clustered, identifying residual pockets of transmission is important for research and for targeting interventions. Malarial antibody-based surveillance is increasingly recognised as a valuable complement to classic methods for the detection of infection foci especially at low transmission levels. The study presents serological evidence for transmission heterogeneity among school children in The Gambia measured during the dry, non-transmission season.Methods: Healthy primary school children were randomly selected from 30 schools across the country and screened for malaria infection (microscopy) and antimalarial antibodies (MSP119). Antibody distribution was modelled using 2-component finite mixture model with cut-off for positivity from pooled sera set at 2-standard deviation from the mean of the first component. Factors associated with a positive serological status were identified in a univariate model and then combined in a multilevel mixed-effects logistic regression model, simultaneously adjusting for variations between individuals and school.Results: A total of 4140 children, 1897 (46%) boys, were enrolled with mean age of 10.2 years (SD 2.6, range 4-20 years). Microscopy results available for 3640 (87.9%) children showed that 1.9% (69) were positive for Plasmodium falciparum infections, most of them (97.1%, 67/69) asymptomatic. The overall seroprevalence was 12.7% (527/4140) with values for the schools ranging from 0.6% to 43.8%. Age (OR 1.12, 95% CI 1.07-1.16,) and parasite carriage (OR 3.36, 95% CI 1.95-5.79) were strongly associated with seropositivity.Conclusion: Serological responses to malaria parasites could identify individuals who were or had been infected, and clusters of residual transmission. Field-adapted antibody tests able to guide mass screening and treatment campaigns would be extremely useful.