Declining burden of malaria over two decades in a rural community of Muheza district, north-eastern Tanzania
Declining burden of malaria over two decades in a rural community of Muheza district, north-eastern Tanzania
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DOI：
10.1186/1475-2875-12-338
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发表时间：
2013-09-22
期刊：
影响因子：
3
通讯作者：
Bygbjerg, Ib C.
中科院分区：
文献类型：
--
作者：
Ishengoma, Deus S.;Mmbando, Bruno P.;Bygbjerg, Ib C.
背景：最近报告的一些非洲国家疟疾负担的下降归因于扩大不同干预措施的规模，尽管在一些地区，这些变化是在实施重大干预措施之前就开始的。本研究评估了坦桑尼亚东北部穆赫扎地区马戈达20年(1992-2012年)和姆帕帕尤村(MPapayu)15年疟疾负担的长期趋势，与不同的干预措施以及国家疟疾控制政策的变化有关。方法：重复横断面调查从这两个村庄收集0~19岁的个体，采集血涂片进行镜检。对恶性疟原虫感染率和疟疾负担的其他指标(贫血、脾肿大和配子细胞的患病率)进行了多年来和研究村之间的比较。主要干预措施包括流动诊所、蚊帐和其他研究活动，以及国家疟疾控制政策的变化。结果：在马戈达，恶性疟原虫感染率在1992-1996年间开始下降(从83.5%下降到62.0%)，在1996-1997年稳定下来，2004年进一步下降到34.4%。2004年至2008年间的短暂增长之后，2012年逐步下降至7.2%，自1992年以来下降了10倍以上。在姆帕帕尤(自1998年以来)，最高患病率为1999年的81.5%，2004年下降到25%。在2008年略有增长后，随后稳步下降，从2011年起达到5%。从1999年到2004年，这两个村庄的蚊帐使用率都很高(>；=88%)，但在2008年到2012年期间有所下降(范围在28%-68%)。在调整了蚊帐、年龄、发烧和学习年份的影响后，1999年至2012年期间，两个村庄感染恶性疟原虫的风险显著下降了97%(p<；0.001)。两个村庄的脾肿大(40%至1%)和配子细胞(23%至1%)的患病率也有所下降。讨论和结论：1992-2012年疟疾负担显著下降，最初的下降(1992-2004年)很可能是由于采取了蚊帐等干预措施，以及通过研究活动提供了更好的服务。除了毒品政策的变化外，2008年以来的稳步下降是在蚊帐覆盖率低的情况下出现的，这表明其他因素导致了最近的模式。这些结果表明，需要继续监测，以确定疟疾流行病学变化的原因，并监测在保持疟疾低传播率和实现相关千年发展目标方面的进展情况。
Background: The recently reported declining burden of malaria in some African countries has been attributed to scaling-up of different interventions although in some areas, these changes started before implementation of major interventions. This study assessed the long-term trends of malaria burden for 20 years (1992-2012) in Magoda and for 15 years in Mpapayu village of Muheza district, north-eastern Tanzania, in relation to different interventions as well as changing national malaria control policies.Methods: Repeated cross-sectional surveys recruited individuals aged 0 - 19 years from the two villages whereby blood smears were collected for detection of malaria parasites by microscopy. Prevalence of Plasmodium falciparum infections and other indices of malaria burden (prevalence of anaemia, splenomegaly and gametocytes) were compared across the years and between the study villages. Major interventions deployed including a mobile clinic, bed nets and other research activities, and changes in national malaria control policies were also marked.Results: In Magoda, the prevalence of P. falciparum infections initially decreased between 1992 and 1996 (from 83.5 to 62.0%), stabilized between 1996 and 1997, and further declined to 34.4% in 2004. A temporary increase between 2004 and 2008 was followed by a progressive decline to 7.2% in 2012, which is more than 10-fold decrease since 1992. In Mpapayu (from 1998), the highest prevalence was 81.5% in 1999 and it decreased to 25% in 2004. After a slight increase in 2008, a steady decline followed, reaching < 5% from 2011 onwards. Bed net usage was high in both villages from 1999 to 2004 (>= 88%) but it decreased between 2008 and 2012 (range, 28% - 68%). After adjusting for the effects of bed nets, age, fever and year of study, the risk of P. falciparum infections decreased significantly by >= 97% in both villages between 1999 and 2012 (p < 0.001). The prevalence of splenomegaly (> 40% to < 1%) and gametocytes (23% to < 1%) also decreased in both villages.Discussion and conclusions: A remarkable decline in the burden of malaria occurred between 1992 and 2012 and the initial decline (1992 - 2004) was most likely due to deployment of interventions, such as bed nets, and better services through research activities. Apart from changes of drug policies, the steady decline observed from 2008 occurred when bed net coverage was low suggesting that other factors contributed to the most recent pattern. These results suggest that continued monitoring is required to determine causes of the changing malaria epidemiology and also to monitor the progress towards maintaining low malaria transmission and reaching related millennium development goals.