Section of Health Services Research, Department of Public Health, University of Copenhagen, Øster Farimagsgade 5B, DK-1014, Copenhagen K, Denmark.
Malar J. 2011 Jul 13;10:188. doi: 10.1186/1475-2875-10-188.
In sub-Saharan Africa (SSA), malaria caused by Plasmodium falciparum has historically been a major contributor to morbidity and mortality. Recent reports indicate a pronounced decline in infection and disease rates which are commonly ascribed to large-scale bed net programmes and improved case management. However, the decline has also occurred in areas with limited or no intervention. The present study assessed temporal changes in Anopheline populations in two highly malaria-endemic communities of NE Tanzania during the period 1998-2009.
Between 1998 and 2001 (1st period) and between 2003 and 2009 (2nd period), mosquitoes were collected weekly in 50 households using CDC light traps. Data on rainfall were obtained from the nearby climate station and were used to analyze the association between monthly rainfall and malaria mosquito populations.
The average number of Anopheles gambiae and Anopheles funestus per trap decreased by 76.8% and 55.3%, respectively over the 1st period, and by 99.7% and 99.8% over the 2nd period. During the last year of sampling (2009), the use of 2368 traps produced a total of only 14 Anopheline mosquitoes. With the exception of the decline in An. gambiae during the 1st period, the results did not reveal any statistical association between mean trend in monthly rainfall and declining malaria vector populations.
A longitudinal decline in the density of malaria mosquito vectors was seen during both study periods despite the absence of organized vector control. Part of the decline could be associated with changes in the pattern of monthly rainfall, but other factors may also contribute to the dramatic downward trend. A similar decline in malaria vector densities could contribute to the decrease in levels of malaria infection reported from many parts of SSA.
在撒哈拉以南非洲（SSA），由恶性疟原虫引起的疟疾一直是发病率和死亡率的主要原因。最近的报告表明，感染和疾病率显著下降，通常归因于大规模的蚊帐计划和改进的病例管理。然而，在干预有限或没有干预的地区，这种下降也已经发生。本研究评估了 1998 年至 2009 年期间坦桑尼亚东北部两个高度疟疾流行社区的按蚊种群的时间变化。
在 1998 年至 2001 年（第一期）和 2003 年至 2009 年（第二期）之间，每周使用 CDC 诱蚊灯在 50 户家庭中收集蚊子。降雨量数据来自附近的气候站，并用于分析每月降雨量与疟疾蚊子种群之间的关系。
在第一期，每个诱蚊灯捕获的冈比亚按蚊和致倦库蚊数量分别减少了 76.8%和 55.3%，在第二期分别减少了 99.7%和 99.8%。在采样的最后一年（2009 年），使用 2368 个诱蚊灯总共只捕获了 14 只按蚊。除了第一期冈比亚按蚊数量下降外，每月降雨量的平均趋势与疟疾媒介种群下降之间没有发现任何统计学关联。
尽管没有组织的媒介控制，但在两个研究期间都观察到疟疾蚊子密度的纵向下降。下降的部分原因可能与每月降雨量模式的变化有关，但其他因素也可能导致急剧下降趋势。疟疾媒介密度的类似下降可能有助于解释来自 SSA 许多地区报告的疟疾感染水平下降。
