Prakash A, Bhattacharyya D R, Mohapatra P K, Mahanta J
Regional Medical Research Centre, NE Region (Indian Council of Medical Research), Dibrugarh, Assam, India.
Vector Borne Zoonotic Dis. 2001 Fall;1(3):231-7. doi: 10.1089/153036601753552594.
To estimate the vectorial capacity of Anopheles dirus, the main vector of forest malaria in the northeastern region of India, in order to gain an understanding of entomological factors related to malaria transmission in forest-fringe areas of Assam, India, an isolated village in the tropical rain forest-fringed area in the district of Dibrugarh, Assam, under the influence of An. dirus alone was studied. Data on various entomological variables required for computation of the vectorial capacity were generated in each month from June 1999 to May 2000 in the field using standard techniques. Malaria prevalence was also studied during the same period in the study village and correlated with the estimated vectorial capacity of An. dirus. Vectorial capacity of An. dirus was highest, 0.779 for Plasmodium vivax (Pv) and 0.649 for Plasmodium falciparum (Pf), during the hot-monsoon season (June-September) and decreased to 0.08 (Pv) and 0.07(Pf) in the temperate postmonsoon season (October-November) before attaining zero values in the cool-dry season (December-February). With increasing temperature in the temperate premonsoon season (March-May), vectorial capacity recorded was 0.119 and 0.82 for Pv and Pf, respectively. Significant positive correlation was seen between the estimated vectorial capacity of An. dirus and the number of new Pf (r = 0.86, p < 0.001) and Pv (r = 0.69, p < 0.02) cases in the study village in different months. Thus, this study highlights the pattern of malaria transmission by An. dirus in a forest-fringe area of Assam that begins in March, peaks in July/August, subsides by November, and remains interrupted between December and February. Measures for controlling malaria in forest-fringe areas should be scheduled accordingly.
为了评估印度东北部森林型疟疾的主要传播媒介——大劣按蚊的传播能力，以便了解印度阿萨姆邦森林边缘地区与疟疾传播相关的昆虫学因素，对位于阿萨姆邦迪布鲁格尔区热带雨林边缘地区、仅受大劣按蚊影响的一个孤立村庄进行了研究。1999年6月至2000年5月期间，每月在实地使用标准技术收集计算传播能力所需的各种昆虫学变量数据。同时，对研究村庄同期的疟疾流行情况进行了研究，并将其与估算的大劣按蚊传播能力相关联。大劣按蚊的传播能力在炎热季风季节（6月至9月）最高，间日疟原虫（Pv）为0.779，恶性疟原虫（Pf）为0.649；在温带季风后季节（10月至11月）降至0.08（Pv）和0.07（Pf），在凉爽干燥季节（12月至2月）则降为零。在温带季风前季节（3月至5月），随着气温升高，Pv和Pf的传播能力分别为0.119和0.82。不同月份研究村庄中，估算的大劣按蚊传播能力与新感染Pf（r = 0.86，p < 0.001）和Pv（r = 0.69，p < 0.02）病例数之间存在显著正相关。因此，本研究突出了阿萨姆邦森林边缘地区大劣按蚊传播疟疾的模式，即从3月开始，7月/8月达到高峰，11月消退，12月至2月期间传播中断。森林边缘地区的疟疾控制措施应据此安排。
