Kitua A Y, Smith T, Alonso P L, Masanja H, Urassa H, Menendez C, Kimario J, Tanner M
Ifakara Centre, Tanzania.
Trop Med Int Health. 1996 Aug;1(4):475-84. doi: 10.1046/j.1365-3156.1996.d01-89.x.
A longitudinal study of Plasmodium falciparum malaria in infants in Idete village, south-eastern Tanzania, was conducted over a period of 14 months in order to determine the incidence of P. falciparum infection and clinical malaria in the first year of life. Of 1356 blood slides from cross-sectional surveys, 52.1% were positive for asexual stages of P. falciparum. There were marked increases in P. falciparum prevalence, parasite densities, overall fever incidence and the incidence of malaria fevers with age for the first 6 months of life. The average attack rate, estimated from a reversible catalytic model, was 0.029 per day with a slight increase with age but there was no initial period of protection against infection in neonates. Estimated average duration of infections was 64 days, with infections in older infants lasting much longer than those contracted during the first 2 months of life. These results support the hypotheses that the main effect of passively transferred maternal immunity to malaria is in the control of asexual stage parasites, and that the level of clinical immunity depends upon the extent of recent exposure to parasites. Infants as young as 4 months of age are at high risk of clinical attacks. Intervention programmes against malaria in areas of the highest transmission should therefore be designed to include this group.
在坦桑尼亚东南部的伊德特村，对婴儿的恶性疟原虫疟疾进行了为期14个月的纵向研究，以确定生命第一年中恶性疟原虫感染和临床疟疾的发病率。在横断面调查的1356份血片中，52.1%的恶性疟原虫无性阶段呈阳性。在生命的前6个月中，恶性疟原虫的流行率、寄生虫密度、总体发热发病率和疟疾发热发病率均随年龄显著增加。根据可逆催化模型估计，平均攻击率为每天0.029，随年龄略有增加，但新生儿没有初始的抗感染保护期。估计平均感染持续时间为64天，年龄较大婴儿的感染持续时间比生命最初2个月感染的持续时间长得多。这些结果支持以下假设：被动转移的母体疟疾免疫力的主要作用是控制无性阶段寄生虫，临床免疫水平取决于近期接触寄生虫的程度。4个月大的婴儿临床发作风险很高。因此，在传播率最高的地区，针对疟疾的干预计划应设计为将这一年龄组纳入其中。
