Quantitative dynamics of Plasmodium yoelii sporozoite transmission by infected anopheline mosquitoes
Quantitative dynamics of Plasmodium yoelii sporozoite transmission by infected anopheline mosquitoes
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DOI：
10.1128/iai.73.7.4363-4369.2005
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发表时间：
2005-07-01
影响因子：
3.1
通讯作者：
Sinnis, P
中科院分区：
文献类型：
--
作者：
Medica, DL;Sinnis, P
疟疾的传播始于受感染的按蚊将疟原虫子孢子注射到脊椎动物宿主的皮肤中。虽然子孢子接种物的大小可能影响疾病的进程，但受感染蚊子注射的子孢子数量尚未在体内确定。使用定量PCR分析，我们确定了由单个蚊子注射到小鼠体内的子孢子的数量。对59次蚊子喂食的分析表明，一只受感染的蚊子注射了0到1,297个子孢子，平均数为123个，中位数为18个。22%的受感染蚊子没有注射子孢子。注射的子孢子数量与唾液腺负荷仅弱相关。为了更好地了解蚊子之间子孢子注射的巨大差异，我们量化了个体蚊子在三个不同日期注射的子孢子。大约20%的中度至重度感染的蚊子在所有3天内注射很少或没有子孢子，表明一些蚊子是子孢子的不良传播者。其他蚊子在观察到的至少一天注射大量子孢子，而在其他日子注射少量子孢子，支持子孢子注射是不连续的假设，这种模式可能有助于建立疟疾感染。
Malaria transmission begins with the injection of Plasmodium sporozoites into the skin of a vertebrate host by infected anopheline mosquitoes. Although the size of the sporozoite inoculum likely affects the course of the disease, the number of sporozoites injected by infected mosquitoes has not been determined in vivo. Using a quantitative PCR assay, we determined the number of sporozoites injected into mice by single mosquitoes. Analysis of 59 mosquito feedings showed that a single infected mosquito injected between 0 and 1,297 sporozoites, with a mean of 123 and a median of 18. Twenty-two percent of infected mosquitoes injected no sporozoites. The number of sporozoites injected was only weakly correlated to the salivary gland load. To better understand the large variability in sporozoite injection among mosquitoes, we quantified the sporozoites injected by individual mosquitoes on three different days. Approximately 20% of moderately to heavily infected mosquitoes injected few to no sporozoites on all 3 days, suggesting that some mosquitoes are poor transmitters of sporozoites. Other mosquitoes injected high numbers of sporozoites on at least one of the days observed and minimal numbers on the other day(s), supporting the hypothesis that sporozoite injection is discontinuous, a pattern that may aid in the establishment of malaria infection.