Schellenberg David, Menendez Clara, Aponte John, Guinovart Caterina, Mshinda Hassan, Tanner Marcel, Alonso Pedro
Centre for International Health, Institut de Investigaciones Biomedicas August Pi I Sunyer, Barcelona, Spain.
Trop Med Int Health. 2004 Jan;9(1):68-76. doi: 10.1046/j.1365-3156.2003.01161.x.
Between 1995 and 2000 there were marked changes in the epidemiology of malaria in Ifakara, southern Tanzania. We documented these changes using parasitological and clinical data from a series of community- and hospital-based studies involving children up to the age of 5 years. There was a right shift and lowering in the age-specific parasite prevalence in the community-based cohort studies. The incidence of clinical malaria in placebo-receiving infants in additional study cohorts dropped from 0.8 in 1995 to 0.43 episodes per infant per year in 2000, an incidence rate ratio of 0.53 (95% confidence interval: 0.404, 0.70, P<0.0001). At the same time, there was an increase in the total number of malaria admissions and a marked right shift in the age pattern of these admissions (median age in 1995 1.55 years vs. 2.33 in 2000, P<0.0001). However, the burden of malaria deaths remained in infants. We discuss how these dramatic changes in the epidemiology of malaria may have arisen from the use of currently available malaria control tools. Caution is required in the interpretation of hospital-based data as it is likely to underestimate the impact of anaemia on mortality in the community, where most paediatric deaths occur. Even in low/moderate malaria transmission settings, where older children suffer most malaria episodes, targeting effective malaria control at infants may produce important reductions in infant mortality caused by malaria.
1995年至2000年间，坦桑尼亚南部伊法卡拉的疟疾流行病学出现了显著变化。我们利用一系列基于社区和医院的研究中的寄生虫学和临床数据记录了这些变化，这些研究涉及5岁以下儿童。在基于社区的队列研究中，特定年龄的寄生虫感染率出现了右移和下降。在其他研究队列中，接受安慰剂的婴儿临床疟疾发病率从1995年的0.8降至2000年的每名婴儿每年0.43次发作，发病率比为0.53（95%置信区间：0.404，0.70，P<0.0001）。与此同时，疟疾住院总数有所增加，且这些住院病例的年龄模式出现明显右移（1995年的中位年龄为1.55岁，2000年为2.33岁，P<0.0001）。然而，疟疾死亡负担仍集中在婴儿身上。我们讨论了疟疾流行病学的这些巨大变化可能是如何由目前可用的疟疾控制工具的使用引起的。在解释基于医院的数据时需要谨慎，因为它可能低估了贫血对社区死亡率的影响，而社区中大多数儿童死亡都发生在那里。即使在疟疾传播程度低/中等的地区，年龄较大的儿童疟疾发作最为频繁，但针对婴儿进行有效的疟疾控制可能会大幅降低疟疾导致的婴儿死亡率。
