Department of Infectious Disease Epidemiology, London School of Tropical Medicine and Hygiene, London, United Kingdom.
PLoS One. 2013 Jun 7;8(6):e65787. doi: 10.1371/journal.pone.0065787. Print 2013.
Malaria prevalence remains high in many African countries despite massive scaling-up of insecticide treated nets (ITN) and indoor residual spraying (IRS). This paper evaluates the protective effect of pyrethroid IRS and ITNs in relation to risk factors for malaria based on a study conducted in North-West Tanzania, where IRS has been conducted since 2007 and universal coverage of ITNs has been carried out recently. In 2011 community-based cross-sectional surveys were conducted in the two main malaria transmission periods that occur after the short and long rainy seasons. These included 5,152 and 4,325 children aged 0.5-14 years, respectively. Data on IRS and ITN coverage, household demographics and socio-economic status were collected using an adapted version of the Malaria Indicator Survey. Children were screened for malaria by rapid diagnostic test. In the second survey, haemoglobin density was measured and filter paper blood spots were collected to determine age-specific sero-prevalence in each community surveyed. Plasmodium falciparum infection prevalence in children 0.5-14 years old was 9.3% (95%CI:5.9-14.5) and 22.8% (95%CI:17.3-29.4) in the two surveys. Risk factors for infection after the short rains included households not being sprayed (OR = 0.39; 95%CI:0.20-0.75); low community net ownership (OR = 0.45; 95%CI:0.21-0.95); and low community SES (least poor vs. poorest tertile: OR = 0.13, 95%CI:0.05-0.34). Risk factors after the long rains included household poverty (per quintile increase: OR = 0.89; 95%CI:0.82-0.97) and community poverty (least poor vs. poorest tertile: OR = 0.26, 95%CI:0.15-0.44); household IRS or high community ITN ownership were not protective. Despite high IRS coverage and equitable LLIN distribution, poverty was an important risk factor for malaria suggesting it could be beneficial to target additional malaria control activities to poor households and communities. High malaria prevalence in some clusters and the limited protection given by pyrethroid IRS and LLINs suggest that it may be necessary to enhance established vector control activities and consider additional interventions.
尽管大规模推广了经杀虫剂处理的蚊帐（ITN）和室内滞留喷洒（IRS），但许多非洲国家的疟疾发病率仍然很高。本文评估了拟除虫菊酯 IRS 和 ITN 对疟疾风险因素的保护作用，该研究是在坦桑尼亚西北部进行的，自 2007 年以来一直在进行 IRS，最近已实现 ITN 的普遍覆盖。2011 年，在两个主要的疟疾传播期（短雨季和长雨季之后）进行了基于社区的横断面调查。分别有 5152 名和 4325 名 0.5-14 岁的儿童参加了这些调查。使用改良的疟疾指标调查版本收集了 IRS 和 ITN 覆盖、家庭人口统计学和社会经济地位的数据。通过快速诊断测试对儿童进行疟疾筛查。在第二次调查中，测量了血红蛋白密度并收集了滤纸条血斑，以确定每个调查社区的年龄特异性血清流行率。0.5-14 岁儿童中恶性疟原虫感染的流行率为 9.3%（95%CI：5.9-14.5）和 22.8%（95%CI：17.3-29.4）。短雨季过后感染的风险因素包括未喷洒的家庭（OR=0.39；95%CI：0.20-0.75）；社区拥有蚊帐比例低（OR=0.45；95%CI：0.21-0.95）；和低社区 SES（最不贫困与最贫困三分位组相比：OR=0.13，95%CI：0.05-0.34）。长雨季过后的风险因素包括家庭贫困（每增加一个五分位数：OR=0.89；95%CI：0.82-0.97）和社区贫困（最不贫困与最贫困三分位组相比：OR=0.26，95%CI：0.15-0.44）；家庭 IRS 或高社区 ITN 拥有量并没有起到保护作用。尽管 IRS 覆盖率高且 LLIN 分配公平，但贫困仍是疟疾的一个重要风险因素，这表明针对贫困家庭和社区开展额外的疟疾控制活动可能会有所裨益。一些集群中的疟疾高流行率以及拟除虫菊酯 IRS 和 LLIN 提供的有限保护作用表明，可能有必要加强现有的病媒控制活动，并考虑采取其他干预措施。
