Modelling the Impact of Artemisinin Combination Therapy and Long-Acting Treatments on Malaria Transmission Intensity

被引:108
作者
Okell, Lucy C. [1 ]
Drakeley, Chris J. [1 ]
Bousema, Teun [2 ]
Whitty, Christopher J. M. [1 ]
Ghani, Azra C. [3 ]
机构
[1] London Sch Hyg & Trop Med, Dept Infect & Trop Dis, London WC1, England
[2] Radboud Univ Nijmegen, Med Ctr, Dept Med Microbiol, NL-6525 ED Nijmegen, Netherlands
[3] Univ London Imperial Coll Sci Technol & Med, Dept Infect Dis Epidemiol, MRC Ctr Outbreak Anal & Modelling, London, England
来源
PLOS MEDICINE | 2008年 / 5卷 / 11期
基金
英国医学研究理事会; 英国惠康基金;
关键词
D O I
10.1371/journal.pmed.0050226
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Background Artemisinin derivatives used in recently introduced combination therapies (ACTs) for Plasmodium falciparum malaria significantly lower patient infectiousness and have the potential to reduce population-level transmission of the parasite. With the increased interest in malaria elimination, understanding the impact on transmission of ACT and other antimalarial drugs with different pharmacodynamics becomes a key issue. This study estimates the reduction in transmission that may be achieved by introducing different types of treatment for symptomatic P. falciparum malaria in endemic areas. Methods and Findings We developed a mathematical model to predict the potential impact on transmission outcomes of introducing ACT as first-line treatment for uncomplicated malaria in six areas of varying transmission intensity in Tanzania. We also estimated the impact that could be achieved by antimalarials with different efficacy, prophylactic time, and gametocytocidal effects. Rates of treatment, asymptomatic infection, and symptomatic infection in the six study areas were estimated using the model together with data from a cross-sectional survey of 5,667 individuals conducted prior to policy change from sulfadoxine-pyrimethamine to ACT. The effects of ACT and other drug types on gametocytaemia and infectiousness to mosquitoes were independently estimated from clinical trial data. Predicted percentage reductions in prevalence of infection and incidence of clinical episodes achieved by ACT were highest in the areas with low initial transmission. A 53% reduction in prevalence of infection was seen if 100% of current treatment was switched to ACT in the area where baseline slide-prevalence of parasitaemia was lowest (3.7%), compared to an 11% reduction in the highest-transmission setting (baseline slide prevalence = 57.1%). Estimated percentage reductions in incidence of clinical episodes were similar. The absolute size of the public health impact, however, was greater in the highest-transmission area, with 54 clinical episodes per 100 persons per year averted compared to five per 100 persons per year in the lowest-transmission area. High coverage was important. Reducing presumptive treatment through improved diagnosis substantially reduced the number of treatment courses required per clinical episode averted in the lower-transmission settings although there was some loss of overall impact on transmission. An efficacious antimalarial regimen with no specific gametocytocidal properties but a long prophylactic time was estimated to be more effective at reducing transmission than a short-acting ACT in the highest-transmission setting. Conclusions Our results suggest that ACTs have the potential for transmission reductions approaching those achieved by insecticide-treated nets in lower-transmission settings. ACT partner drugs and nonartemisinin regimens with longer prophylactic times could result in a larger impact in higher-transmission settings, although their long term benefit must be evaluated in relation to the risk of development of parasite resistance.
引用
收藏
页码:1617 / 1628
页数:12
相关论文
共 68 条
[1]  
[Anonymous], 2007, LANCET, V370, P1459
[2]  
[Anonymous], 2015, Guidelines for the treatment of malaria
[3]  
Aron J.L., 1982, P139
[4]   Seasonal malaria attack rates in infants and young children in northern Ghana [J].
Baird, JK ;
Agyei, SO ;
Utz, GC ;
Koram, K ;
Barcus, MJ ;
Jones, TR ;
Fryauff, DJ ;
Binka, FN ;
Hoffman, SL ;
Nkrumah, FN .
AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 2002, 66 (03) :280-286
[5]   Effect of artemether-lumefantrine policy and improved vector control on malaria burden in KwaZulu-Natal, South Africa [J].
Barnes, KI ;
Durrheim, DN ;
Little, F ;
Jackson, A ;
Mehta, U ;
Allen, E ;
Dlamini, SS ;
Tsoka, J ;
Bredenkamp, B ;
Mthembu, DJ ;
White, NJ ;
Sharp, BL .
PLOS MEDICINE, 2005, 2 (11) :1123-1134
[6]   Impact of artemisinin-based combination therapy and insecticide-treated nets on malaria burden in Zanzibar [J].
Bhattarai, Achuyt ;
Ali, Abdullah S. ;
Kachur, S. Patrick ;
Martensson, Andreas ;
Abbas, Ali K. ;
Khatib, Rashid ;
Al-Mafazy, Abdul-wahiyd ;
Ramsan, Mahdi ;
Rotllant, Guida ;
Gerstenmaier, Jan F. ;
Molteni, Fabrizio ;
Abdulla, Salim ;
Montgomery, Scott M. ;
Kaneko, Akira ;
Bjorkman, Anders .
PLOS MEDICINE, 2007, 4 (11) :1784-1790
[7]   Public health impact of drug resistant Plasmodium falciparum malaria [J].
Björkman, AB ;
Bhattarai, A .
ACTA TROPICA, 2005, 94 (03) :163-169
[8]   Relationship between altitude and intensity of malaria transmission in the Usambara Mountains, Tanzania [J].
Bodker, R ;
Akida, J ;
Shayo, D ;
Kisinza, W ;
Msangeni, HA ;
Pedersen, EM ;
Lindsay, SW .
JOURNAL OF MEDICAL ENTOMOLOGY, 2003, 40 (05) :706-717
[9]   Estimation of malaria transmission from humans to mosquitoes in two neighbouring villages in south Cameroon: evaluation and comparison of several indices [J].
Bonnet, S ;
Gouagna, LC ;
Paul, RE ;
Safeukui, I ;
Meunier, JY ;
Boudin, C .
TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE, 2003, 97 (01) :53-59
[10]   A major transition in malaria treatment: The adoption and deployment of artemisinin-based combination therapies [J].
Bosman, Andrea ;
Mendis, Kamini N. .
AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 2007, 77 (06) :193-197