Incidence of symptomatic and asymptomatic Plasmodium falciparum infection following curative therapy in adult residents of northern Ghana
Incidence of symptomatic and asymptomatic Plasmodium falciparum infection following curative therapy in adult residents of northern Ghana
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DOI：
10.4269/ajtmh.2001.65.197
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发表时间：
2001-09-01
影响因子：
3.3
通讯作者：
Hoffman, SL
中科院分区：
文献类型：
--
作者：
Owusu-Agyei, S;Koram, KA;Hoffman, SL
非洲疟疾大流行地区的成年居民对疟疾具有天然获得性免疫力（NAI），这使他们对新感染具有更强的抵抗力，限制寄生虫血症，并降低疾病的频率和严重程度。鉴于这些属性，目前尚不清楚如何在不出现严重混淆的情况下评估成人药物或疫苗的功效。为了确定加纳北部成年人有症状和无症状疟疾的发病率，197 名男性和女性在高传播（湿）季节开始时接受了针对任何先前存在的疟疾感染的治疗。在 20 周内（1996 年 5 月至 10 月）对他们进行了首次寄生虫血症和首次恶性疟原虫感染临床发作的监测。恶性疟原发感染累计发生率为0.98，感染发生密度为7.0例/人年。 19.5% 的人在首次出现寄生虫血症复发时报告有症状。男性和女性的感染发生率、寄生虫密度和症状频率相当。结果表明，NAI 没有为这些成年人提供针对快速再次感染的有效防御，并表明这种群体感染设计可以用来证明药物或疫苗在预防寄生虫血症方面的功效。
Adult residents of holoendemic malaria regions in Africa have a naturally acquired immunity (NAI) to malaria that renders them more resistant to new infections, limits parasitemia, and reduces the frequency and severity of illness. Given such attributes, it is not clear how one might evaluate drug or vaccine efficacy in adults without serious confounding. To determine symptomatic and asymptomatic malaria attack rates in adults of northern Ghana, 197 men and women underwent curative therapy for any pre-existing malaria infections at the start of the high transmission (wet) season. They were monitored for first parasitemia and first clinical episode of infection by Plasmodium falciparum over a 20-week period (May-October 1996). The cumulative incidence of primary infection by P. falciparum was 0.98 and incidence density of infection was calculated to be 7.0 cases/person-year. Symptoms were reported by 19.5% of the individuals at the time of first recurrent parasitemia. Incidence of infection, parasite density, and the frequency of symptoms were comparable in males and females. The results suggest that NAI did not provide these adults with significant defense against rapid re-infection and suggest that this population-infection design could serve to demonstrate the efficacy of a drug or vaccine in preventing parasitemia.