A.Tiono, Centre National de Recherche et de Formation sur le Paludisme - Investigating the Human Malaria Reservoir of Transmission during Pregnancy

疟疾每年影响数百万人，对儿童和孕妇危害最大。然而，近年来在控制疟疾方面取得了相当大的成功，降低了感染和死亡的水平。这是通过大量使用蚊帐和提供有效药物实现的。这一成功促使许多国家考虑彻底消灭疟疾。消除疟疾将需要额外和不同的方法，因为有必要确定将感染传播给蚊子的人。这些可能与那些生病的人不同。一些研究表明，有些人的疟原虫水平较低，但没有症状，还有一些研究表明，这些低水平的感染可以传播给蚊子。因此，目前关于谁可能将寄生虫传播给蚊子的数据少得惊人。了解这一点很重要，因为它将有助于设计控制疟疾的方法，这些方法在工作速度和实施成本方面都将更加有效。例如，如果我们知道谁是主要的人群或群体，那么就更容易针对他们进行具体的定位。有一群人实际上更有可能感染蚊子，那就是孕妇。疟疾对孕妇尤其有害，因为胎盘为寄生虫的发育和生长提供了新的环境。正因为如此，孕妇感染的机会更高，当她们被感染时，寄生虫的数量比未怀孕的妇女或同龄男子要多。在怀孕期间第一次或第二次感染的妇女风险最大。任何地方都有1%到5%的人口在同一时间怀孕，因此这是潜在感染和传染性个体的相当大比例。在这项研究中，我们的目标是计算孕妇对疟疾传播的贡献。为了做到这一点，我们将描述与人群中其他成员相比，孕妇体内可以感染蚊子的疟疾寄生虫的阶段水平。我们还将观察这些寄生虫是否在孕妇的特定部位被发现。我们还将检查孕妇是否比非孕妇和其他成员更容易被蚊子叮咬和感染蚊子。最后，我们将把这些数据结合在一系列模拟中，以找出预防孕妇传播的最佳方法，以便我们能够在有必要关注孕妇的情况下为疟疾控制规划提供建议，以及如果有必要，应该如何做到这一点。

Malaria affects millions of individuals annually and is most harmful to children and pregnant women. However, in recent years there has been considerable success in controlling malaria reducing the levels of both infections and deaths. This has been achieved by high levels of use mosquito nets and the availability of effective drugs. This success has prompted many countries to think about eliminating malaria altogether. Eliminating malaria will require additional and different approaches in that it will be necessary to identify people who transmit the infection to mosquitoes. These may be different to those who are sick. A number of studies have shown that there are individuals with low levels of malaria parasites who are asymptomatic and a few studies show that these low level infections can be transmitted to mosquitoes. So, at the moment there is surprisingly little data on who might transmit the parasites to mosquitoes. This is important to know because it will help design approaches to control malaria that will be more effective both in terms of the speed they work and the cost to carry them out. For example, if we know who the main people or groups of people are then it would be easier to target them with specifically.One group of individuals that realistically might infect mosquitoes more are pregnant women. Malaria is particularly harmful to pregnant women as the placenta provides a new environment for parasites to develop and grow in. It is because of this that pregnant women have higher chances of infection and when they are infected have higher numbers of parasites than non-pregnant women or men of the same age. Women in their first or second infections in pregnancy are most at risk. Anywhere between 1 and 5% of the population ae pregnant at one time and thus this is a substantial proportion of potentially infected and infectious individuals.In this study we aim to calculate how much pregnant women contribute to malaria transmission. To do this we will describe the levels of stages of the malaria parasite that can infect mosquitoes in pregnant women compared with other members of the population. We will also see if these parasites are found in specialised locations in pregnant women. We will also check if pregnant women are bitten more by mosquitoes and infect mosquitoes more than non pregnant women and other members. Finally, we will combine these data in a series of simulations to work out what the best approaches to preventing transmission in pregnant women so that we can advise malaria control programmes if a focus on pregnant women is necessary and if so how this should be done.