Malaria studies on the firestone rubber plantation in Liberia, West Africa
Malaria studies on the firestone rubber plantation in Liberia, West Africa
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DOI：
10.1093/oxfordjournals.aje.a117835
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发表时间：
1932-05-01
影响因子：
--
通讯作者：
Brown, JY
中科院分区：
文献类型：
--
作者：
Barber, MA;Rice, JB;Brown, JY
本文记录了1931年2月至5月在利比里亚一个橡胶种植园的一部分进行的调查结果。按蚊密度测量的平均每日渔获量每间客房为7.6二月，6.2三月，和7.0四月，但在5月期间几乎每天下雨，它上升到约9.0。一个Anophelines遇到的名单已经注意到[R.A.E.，B，xx，97].只有冈比亚按蚊Giles（costalis，Theo.），Funestus，Giles，A. nili，Theo.和A. theilerivar.hancocki，Edw.，在住宅中很常见。对前两个物种的大量解剖得出疟疾总感染率为4.3%和3%，子孢子率为3.5%和1.9%。分别A. nili太小，不能作为总感染的可靠指标，但子孢子率为0.8%。theilerivar.hancockidissected.人口的特点和疟疾的发病率在研究的各个营地进行了简要讨论。用A. gambiaeandA. funestus表明，有一个相当自由的传播前者，也可能是后者，在半径近半英里，很可能，这些物种分布在更大的区域。某些营地和房屋的居民在3月5日至4月3日期间接受了plasmochin治疗，1 cgm。一周服用两次，没有任何不良后果。通过测定以10天为间隔在住宅中捕获的按蚊的子孢子率来测量效果。在开始给药后10-15天（这是卵囊成熟所需的大致时间），子孢子指数显著下降，并一直低于对照组，直到停止给药后约14天。在给予最后一剂plasmochin后20天，联合治疗组的子孢子指数等于或超过对照组。在治疗期间，营地中出现了一些受感染的蚊子，这可能是由于它们从种植园未经治疗的部分迁移而来。在配子体载体上的实验表明，在一次剂量的2 cgm后。plasmochin这名男子未能感染蚊子，即使在他的血液中存在新月体至少一周后。建议进行更大规模的实验，以确定是否与plasmochin治疗将是一个实用的抗疟措施在这个种植园.In第二部分的文件，各种按蚊的繁殖场所进行了讨论，并得出结论，地形有利于连续生产的大量。对同一条溪流中树木繁茂的部分和清理干净的部分进行比较，似乎表明清理增加了按蚊的繁殖，特别是主要的疟疾媒介按蚊。gambiaeandA，funestus.对一个较老的种植园的调查表明，植被的重新生长减少了按蚊的产量，但仍然有足够的冈比亚按蚊繁殖，以维持较高的疟疾发病率。只有在村庄的水池中繁殖也得到控制的情况下，允许溪流旁的丛林重新生长才有价值。目前的排水系统只能保护有限的地区。从一个粗略的估计的百分比的老蚊子和蚊子含有子孢子，它的结论是，没有减少其发病率是由日常收集，并在收集后的替代品可能包括大量的老蚊子，其中一些可能来自相当远的距离。另一方面...
This paper records the results of an investigation carried out from February to May 1931 on part of a rubber plantation in Liberia. The Anopheline density as measured by the average daily catch per room was 7.6 for February, 6.2 for March, and 7.0 for April, but in May during a period of almost daily rains it rose to approximately 9.0. A list of the Anophelines encountered has already been noticed [R.A.E., B, xx, 97]. OnlyAnopheles gambiae, Giles (costalis, Theo.),A.funestus, Giles,A. nili, Theo., andA. theilerivar.hancocki, Edw., were common in dwellings. Dissections of large numbers of the first two species yielded total malaria infection rates of 4.3 and 3 per cent. and sporozoite rates of 3.5 and 1.9 per cent., respectively. The number of stomach dissections ofA. niliwas too small to give a reliable index of total infection, but the sporozoite rate was 0.8 per cent. No positive results were obtained with the small number ofA. theilerivar.hancockidissected. The character of the population and the incidence of malaria in the various camps studied is briefly discussed. An experiment with stained individuals ofA. gambiaeandA. funestusshowed that there was a fairly free dispersal of the former, and possibly also of the latter, within a radius of nearly half a mile, and it is probable that these species range over a still greater area. The inhabitants of certain camps and houses were treated with plasmochin between 5th March and 3rd April, 1 cgm. being administered twice a week with no harmful results. The effect was measured by determining the sporozoite rate in Anophelines caught in dwellings at intervals of 10 days. There was a marked drop in the sporozoite index 10-15 days after the beginning of the treatment (this being the approximate time required for the maturation of oöcysts), and it remained below that of the controls until about 14 days after the treatment was discontinued. Twenty days after the last dose of plasmochin had been administered, the sporozoite index of the combined treated camps had equalled or exceeded that of the controls. The presence of a few infected mosquitos in the camps during treatment was probably due to their migration from untreated parts of the plantation. An experiment on a gametocyte carrier showed that after one dose of 2 cgm. plasmochin this man failed to infect mosquitos even though crescents were present in his blood for at least a week afterwards. It is suggested that a larger experiment be made to ascertain whether treatment with plasmochin would be a practical anti-malarial measure on this plantation.In the second part of the paper, the breeding-places of the various Anophelines are discussed, and it is concluded that the terrain favours the continuous production of large numbers. A comparison of wooded and cleared portions of the same streams appeared to show that clearing increased the breeding of Anophelines, particularly the chief malaria vectors,A. gambiaeandA, funestus. A survey of an older plantation indicated that re-growth of vegetation reduced Anopheline production but that there was still sufficient breeding ofA, gambiaeto maintain a high malaria rate. Allowing the re-growth of jungle beside streams would only be of value if breeding in pools in villages were also controlled. Drainage at the present time would only be practical for the protection of a limited area. From a rough estimate of the percentage of older mosquitos and mosquitos containing sporozoites, it is concluded that no reduction in their incidence was made by daily collections, and that replacements after collections may include large numbers of older mosquitos, some of which may come from considerable distances. On the other …