Sabesan Shanmugavelu, Raju Konuganti Hari Kishan, Subramanian Swaminathan, Srivastava Pradeep Kumar, Jambulingam Purushothaman
1 Vector Control Research Centre , Medical Complex, Indira Nagar, Puducherry, India .
Vector Borne Zoonotic Dis. 2013 Sep;13(9):657-65. doi: 10.1089/vbz.2012.1238. Epub 2013 Jun 29.
The strategy adopted by a global program to interrupt transmission of lymphatic filariasis (LF) is mass drug administration (MDA) using chemotherapy. India also followed this strategy by introducing MDA in the historically known endemic areas. All other areas, which remained unsurveyed, were presumed to be nonendemic and left without any intervention. Therefore, identification of LF transmission risk areas in the entire country has become essential so that they can be targeted for intervention. A geo-environmental risk model (GERM) developed earlier was used to create a filariasis transmission risk map for India. In this model, a Standardized Filariasis Transmission Risk Index (SFTRI, based on geo-environmental risk variables) was used as a predictor of transmission risk. The relationship between SFTRI and endemicity (historically known) of an area was quantified by logistic regression analysis. The quantified relationship was validated by assessing the filarial antigenemia status of children living in the unsurveyed areas through a ground truth study. A significant positive relationship was observed between SFTRI and the endemicity of an area. Overall, the model prediction of filarial endemic status of districts was found to be correct in 92.8% of the total observations. Thus, among the 190 districts hitherto unsurveyed, as many as 113 districts were predicted to be at risk, and the remaining at no risk. The GERM developed on geographic information system (GIS) platform is useful for LF spatial delimitation on a macrogeographic/regional scale. Furthermore, the risk map developed will be useful for the national LF elimination program by identifying areas at risk for intervention and for undertaking surveillance in no-risk areas.
全球消除淋巴丝虫病（LF）传播的项目所采用的策略是使用化学疗法进行大规模药物给药（MDA）。印度也采用了这一策略，在历史上已知的流行地区引入了MDA。所有其他未进行调查的地区被假定为非流行区，未采取任何干预措施。因此，确定全国范围内的LF传播风险地区变得至关重要，以便能够针对这些地区进行干预。早期开发的地理环境风险模型（GERM）被用于创建印度的丝虫病传播风险地图。在该模型中，标准化丝虫病传播风险指数（SFTRI，基于地理环境风险变量）被用作传播风险的预测指标。通过逻辑回归分析量化了SFTRI与一个地区的流行程度（历史已知）之间的关系。通过实地调查评估未调查地区儿童的丝虫抗原血症状况，对量化关系进行了验证。观察到SFTRI与一个地区的流行程度之间存在显著的正相关关系。总体而言，发现对各地区丝虫病流行状况的模型预测在92.8%的总观测值中是正确的。因此，在迄今未进行调查的190个地区中，多达113个地区被预测存在风险，其余地区无风险。在地理信息系统（GIS）平台上开发的GERM有助于在宏观地理/区域尺度上对LF进行空间界定。此外，所绘制的风险地图将有助于国家LF消除计划，通过识别有干预风险的地区以及在无风险地区进行监测。
