Barnish G, Maude G H, Bockarie M J, Erunkulu O A, Dumbuya M S, Greenwood B M
Medical Research Council Laboratory, Bo, Sierra Leone.
Ann Trop Med Parasitol. 1993 Apr;87(2):137-48. doi: 10.1080/00034983.1993.11812747.
The prevalence of Plasmodium falciparum in a cohort of over 900 nought to seven-year-old children living in a rural area of Sierra Leone was found to be approximately 61%, both before and after the rainy season. Plasmodium malariae rates measured in the same children were approximately 12%, and P. ovale rates averaged about 1%. Spleen rates averaged 44% for the two surveys; the age prevalence spleen profiles closely matched those for P. falciparum. The overall gametocyte rates for both P. falciparum and P. malariae were roughly one fifth of the prevalence rates for the asexual parasites. However, whilst there was no difference between the P. falciparum gametocyte rates at the two surveys, the P. malariae rate was significantly higher post-rains when compared with the pre-rains result. Spleen size did not increase with increased parasite density. There was a statistically significant difference between the geometric mean P. falciparum trophozoite densities of febrile and afebrile children both before and after the rainy season, but there was little seasonal difference in the means for the febrile children or in those for the afebrile children. Antimalaria antibody levels, measured by ELISA and IFAT, showed no significant differences at either survey. The levels found were high for all age groups, indicating that exposure to malaria begins at birth. Our results indicate that, in the area studied, malaria is hyperendemic and is probably transmitted perennially.
在塞拉利昂农村地区的900多名零至七岁儿童队列中，发现恶性疟原虫的流行率在雨季前后均约为61%。在同一批儿童中测得的三日疟原虫率约为12%，卵形疟原虫率平均约为1%。两次调查的脾肿大率平均为44%；年龄别脾肿大情况与恶性疟原虫的情况密切匹配。恶性疟原虫和三日疟原虫的总体配子体率约为无性寄生虫流行率的五分之一。然而，虽然两次调查的恶性疟原虫配子体率没有差异，但与雨季前相比，三日疟原虫率在雨后显著更高。脾肿大程度并未随寄生虫密度增加而增大。雨季前后，发热儿童和不发热儿童的恶性疟原虫滋养体密度几何平均数均存在统计学显著差异，但发热儿童或不发热儿童的平均数在季节上差异不大。通过酶联免疫吸附测定法（ELISA）和间接荧光抗体试验（IFAT）测量的抗疟疾抗体水平在两次调查中均无显著差异。所有年龄组的抗体水平都很高，表明出生时就开始接触疟疾。我们的结果表明，在所研究的地区，疟疾高度流行，可能常年传播。
