Maximising the impact of chemoprevention on the malaria burden in children in areas of seasonal transmission

最大限度地发挥化学预防对季节性传播地区儿童疟疾负担的影响

• 批准号: MR/J012394/1
• 负责人: Matthew Cairns
• 金额: $ 35.9万
• 依托单位: London School of Hygiene & Tropical Medicine
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FJ012394%2F1
• 关键词: Maximising; impact; chemoprevention; malaria; burden

Malaria is a parasitic disease transmitted by mosquitoes that kills approximately 850,000 people every year, mostly children under five years of age living in sub-Saharan Africa. Prevention of malaria is key to achieving Millennium Development Goals. The epidemiology or disease pattern of malaria varies widely across Africa, both in terms of intensity (the number of infections individuals are exposed to), and seasonality (how the pattern of risk varies over the course of the year).In areas of Africa where malaria is only a problem during a short rainy season, monthly courses of antimalarial drugs can prevent malaria in children very effectively. This approach, called seasonal malaria chemoprevention (SMC), may also be useful in places where malaria is transmitted for longer each year. However, the impact in such areas is not well understood.Another form of prevention that would be easier for African countries to put into practice would be to treat malaria patients with long-lasting artemisinin combination therapies (LACTs), which prevent further malaria infections for several weeks. Malaria does not affect all children equally: a fraction of children repeatedly experience malaria, while other children remain healthy. Repeated malaria leads to severe anaemia, an important cause of death in areas where malaria is endemic. LACTs would prevent some repeated malaria attacks, and may be a simple and effective way to target limited resources at the individuals who most need protection. This may be particularly beneficial in areas with seasonal malaria transmission because repeated malaria attacks are likely to occur close together in time. In such areas, LACTs could help ensure that a child's first attack each year is their last.Dr Matthew Cairns, an epidemiologist based at the London School of Hygiene & Tropical Medicine, will use a multi-disciplinary approach to investigate these issues.Studies of malaria conducted in West Africa will provide data on the epidemiology of malaria in different areas. Data will be analysed to quantify the fraction of the total malaria and anaemia burden that occurs soon after a previous malaria attack, and which might therefore be prevented by replacing standard antimalarials with LACTs. This analysis will also determine the situations in which malaria is most unevenly focused on a small sub-group of children, and identify characteristics associated with high risk. This could lead to changes in which antimalarials are recommended as policy in some parts of Africa. A mathematical model developed by Dr Cairns will be extended to determine the impact of LACTs and SMC in a range of areas, using a range of assumptions about the effectiveness of drugs and the use of treatment by different children. The model will also allow exploration of the impact of combining these two interventions, which might be very expensive to do in a clinical trial. If the predicted impact of SMC is sufficient, this could lead to expansion of the area where SMC is deployed. Data from a clinical trial in Ghana investigating these two forms of prevention (arranged outside the fellowship), will be analysed to determine the real-life impact of these interventions, and help improve the accuracy of the model predictions.Computer based simulations including rainfall and other climatic data will then be used to identify the geographical areas where SMC and LACTs are likely to be useful, and their potential impact on disease and on transmission of malaria. Maps will be produced showing results at sub-country level. Results of the research will help policy makers at the World Health Organisation and in malaria-endemic countries to make decisions on the recommended treatment for malaria, and to plan and prioritise where to deploy these two forms of malaria prevention. Both interventions could have an important impact on the health of African children within the next five years.

疟疾是一种由蚊子传播的寄生虫病，每年造成约85万人死亡，其中大多数是生活在撒哈拉以南非洲的五岁以下儿童。预防疟疾是实现千年发展目标的关键。疟疾的流行病学或疾病模式在非洲各地差异很大，无论是在强度（个人接触感染的数量）方面，还是在季节性（一年中风险模式的变化）方面，在非洲只有在短暂的雨季疟疾才是一个问题的地区，每月的抗疟药物疗程可以非常有效地预防儿童疟疾。这种方法被称为季节性疟疾化学预防（SMC），在疟疾每年传播时间较长的地方也可能有用。另一种对非洲国家来说更容易实施的预防形式是用长效青蒿素综合疗法治疗疟疾患者，这种疗法可以在几周内防止疟疾的进一步感染。疟疾对所有儿童的影响并不相同：一小部分儿童反复感染疟疾，而其他儿童则保持健康。疟疾反复发作导致严重贫血，这是疟疾流行地区的一个重要死因。LACT将防止一些疟疾重复发作，并且可能是将有限的资源用于最需要保护的个人的简单而有效的方法。这在季节性疟疾传播的地区可能特别有益，因为疟疾反复发作的时间可能很接近。在这些地区，LACT可以帮助确保儿童每年的第一次发病是他们的最后一次。伦敦卫生与热带医学学院的流行病学家马修凯恩斯博士将使用多学科方法来调查这些问题。在西非进行的疟疾研究将提供不同地区疟疾流行病学的数据。将对数据进行分析，以量化在上一次疟疾发作后不久发生的疟疾和贫血在疟疾和贫血总负担中所占的比例，因此可以通过用LACT替代标准抗疟药物来预防。这一分析还将确定疟疾最不均衡地集中在一小部分儿童身上的情况，并查明与高风险有关的特征。这可能导致非洲某些地区建议将抗疟药物作为政策的变化。凯恩斯博士开发的一个数学模型将被扩展，以确定LACT和SMC在一系列领域的影响，使用一系列关于药物有效性和不同儿童使用治疗的假设。该模型还将允许探索结合这两种干预措施的影响，这在临床试验中可能非常昂贵。如果SMC的预测影响足够大，这可能导致SMC部署区域的扩大。加纳一项研究这两种预防形式的临床试验的数据（安排在研究金之外），将进行分析，以确定这些干预措施的实际影响，并帮助提高模型预测的准确性。然后将使用计算机模拟，包括降雨量和其他气候数据，以确定SMC和LACT可能有用的地理区域，及其对疾病和疟疾传播的潜在影响。将绘制地图，显示国家以下一级的成果。研究结果将帮助世界卫生组织和疟疾流行国家的决策者就推荐的疟疾治疗方法做出决定，并计划和优先考虑在哪里部署这两种形式的疟疾预防。这两项干预措施在今后五年内可能对非洲儿童的健康产生重要影响。

项目成果

The risk of malaria in Ghanaian infants born to women managed in pregnancy with intermittent screening and treatment for malaria or intermittent preventive treatment with sulfadoxine/pyrimethamine.

• DOI: 10.1186/s12936-016-1094-z
• 发表时间: 2016-01-28
• 期刊: Malaria journal
• 影响因子: 3
• 作者: Awine T;Belko MM;Oduro AR;Oyakhirome S;Tagbor H;Chandramohan D;Milligan P;Cairns M;Greenwood B;Williams JE
• 通讯作者: Williams JE

Seasonal Dynamics of Malaria in Pregnancy in West Africa: Evidence for Carriage of Infections Acquired Before Pregnancy Until First Contact with Antenatal Care.

• DOI: 10.4269/ajtmh.17-0620
• 发表时间: 2018-03
• 期刊: The American journal of tropical medicine and hygiene
• 作者: Berry I;Walker P;Tagbor H;Bojang K;Coulibaly SO;Kayentao K;Williams J;Oduro A;Milligan P;Chandramohan D;Greenwood B;Cairns M
• 通讯作者: Cairns M

Non-malaria fevers in a high malaria endemic area of Ghana.

• DOI: 10.1186/s12879-016-1654-4
• 发表时间: 2016-07-11
• 期刊: BMC infectious diseases
• 影响因子: 3.7
• 作者: Asante KP;Owusu-Agyei S;Cairns M;Boamah E;Manu G;Twumasi M;Gyasi R;Adjei G;Kayan K;Mahama E;Dosoo DK;Koram K;Greenwood B;Chandramohan D
• 通讯作者: Chandramohan D

Cluster randomized trial of text message reminders to retail staff in tanzanian drug shops dispensing artemether-lumefantrine: effect on dispenser knowledge and patient adherence.

• DOI: 10.4269/ajtmh.14-0126
• 发表时间: 2014-10
• 期刊: The American journal of tropical medicine and hygiene
• 作者: Bruxvoort K;Festo C;Kalolella A;Cairns M;Lyaruu P;Kenani M;Kachur SP;Goodman C;Schellenberg D
• 通讯作者: Schellenberg D

Are Tanzanian patients attending public facilities or private retailers more likely to adhere to artemisinin-based combination therapy?

• DOI: 10.1186/s12936-015-0602-x
• 发表时间: 2015-02-19
• 期刊: Malaria journal
• 影响因子: 3
• 作者: Bruxvoort K;Kalolella A;Cairns M;Festo C;Kenani M;Lyaruu P;Kachur SP;Schellenberg D;Goodman C
• 通讯作者: Goodman C