Spatial Risk Model for Ixodes scapularis-Borne Borrelia

肩胛硬蜱-伯氏疏螺旋体的空间风险模型

• 批准号: 6831343
• 负责人: DURLAND FISH
• 金额: $ 68.82万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6831343
• 关键词: Borrelia; Ixodes; North America; animal population density; animal population genetics; arthropod borne communicable disease; arthropod genetics; borreliosis; communicable disease control; communicable disease transmission; computer program /software; cooperative study; disease /disorder model; disease vectors; epizootiology; genotype; geographic difference; host organism interaction; information systems; model design /development; polymerase chain reaction; species difference; statistics /biometry; wild animals; zoonosis

We propose to measure the risk of Borrelia spirochete transmission to humans from Ixodes scapularis ticks throughout its geographic range in the U.S. and to develop and validate a spatially explicit risk model based upon vector population density and Borrelia infection prevalence. The density of host-seeking nymphal [. scapularis will be measured by drag sampling of closed-canopy deciduous forest habitats in selected state 9arks or natural areas at 95 locations spaced among 2 degree grid quadrats covering the known species range. Samples of 100 ticks collected from these sites will be assayed by real-time quantitative polymerase chain reaction (RT-PCR) of the 16S rDNA (rrs) gene for identification of genus Borrelia spirochetes. Further characterization of Borrelia spirochetes to subgenospecies levels will be accomplished by RT-PCR with specific DNA probes and nucleotide sequencing. The species, genospecies,and subgenospecies genetic structure of Borrelia spirochetes found in nymphal I. scapularis at each site will be mathematically expressed in terms of relative frequency. The frequency values will be combined with tick density estimates to estimate the risk of human infection at each sample site. Spatial models, employing remotely-sensed environmental data, geographic information systems, and spatial statistics, will be developed to predict risk in unsampled areas and provide a continuous surface map depicting risk throughout the range of/. scapularis. Sampling will be repeated during each of four project years, providing a total of approximately 400 sampling points and an anticipated 5,000 Borrelia genotype determinations. Data from each subsequent year will be used to validate model prediction from previous years, thus accumulating accuracy over the four-year project. The final product will be a surface map of human risk for infection from I. scapularis-borne Borrelia spirochetes for the U.S.

我们建议在美国的整个地理范围内测量肩突硬蜱将疏螺旋体传播给人类的风险，并根据媒介人口密度和疏螺旋体感染流行率开发和验证空间明确的风险模型。寻寄主若虫的密度。肩胛骨将通过在选定的州9arks或自然区域的封闭树冠落叶林栖息地进行拖曳采样来测量，在覆盖已知物种范围的2度网格样方中间隔95个位置。 将通过16 S rDNA（rrs）基因的实时定量聚合酶链反应（RT-PCR）分析从这些研究中心采集的100只蜱样本，以鉴定疏螺旋体属螺旋体。将通过使用特异性DNA探针的RT-PCR和核苷酸测序来完成疏螺旋体螺旋体亚基因种水平的进一步表征。在若虫中发现的疏螺旋体螺旋体的种、基因种和亚基因种遗传结构。每个部位的肩胛肌将以相对频率进行数学表达。频率值将与蜱虫密度估计值相结合， 每个采样点的人类感染风险。将利用遥感环境数据、地理信息系统和空间统计数据开发空间模型，以预测未抽样地区的风险，并提供一个连续的表面图，描绘整个区域的风险。肩胛肌在四个项目年的每一年将重复取样，总共提供约400个取样点和预计5,000个疏螺旋体基因型测定。随后每年的数据将用于验证前几年的模型预测，从而在四年期项目中积累准确性。最终产品将是人类感染I.肩胛骨传播疏螺旋体螺旋体 为美国