A progressive declining in the burden of malaria in north-eastern Tanzania
Tóm tắt
The planning and assessment of malaria interventions is complicated due to fluctuations in the burden of malaria over time. Recently, it has been reported that the burden of malaria in some parts of Africa has declined. However, community-based longitudinal data are sparse and the reasons for the apparent decline are not well understood. Malaria prevalence and morbidity have been monitored in two villages in north-eastern Tanzania; a lowland village and a highland village from 2003 to 2008. Trained village health workers treated presumptive malaria with the Tanzanian first-line anti-malarial drug and collected blood smears that were examined later. The prevalence of malaria parasitaemia across years was monitored through cross-sectional surveys. The prevalence of malaria parasitaemia in the lowland village decreased from 78.4% in 2003 to 13.0% in 2008, whereas in the highland village, the prevalence of parasitaemia dropped from 24.7% to 3.1% in the same period. Similarly, the incidence of febrile malaria episodes in the two villages dropped by almost 85% during the same period and there was a marked reduction in the number of young children who suffered from anaemia in the lowland village. There has been a marked decline in malaria in the study villages during the past few years. This decline is likely to be due to a combination of factors that include improved access to malaria treatment provided by the trained village helpers, protection from mosquitoes by increased availability of insecticide-impregnated bed nets and a reduced vector density. If this decline in malaria morbidity is sustained, it will have a marked effect on the disease burden in this part of Tanzania.
Tài liệu tham khảo
White NJ, Nosten F, Looareesuwan S, Watkins WM, Marsh K, Snow RW, Kokwaro G, Ouma J, Hien TT, Molyneux ME, Taylor TE, Newbold CI, Ruebush TK, Danis M, Greenwood BM, Anderson RM, Olliaro P: Averting a malaria disaster. Lancet. 1999, 353: 1965-1967. 10.1016/S0140-6736(98)07367-X.
Breman JG: The ears of the hippopotamus: manifestations, determinants, and estimates of the malaria burden. Am J Trop Med Hyg. 2001, 64: 1-11.
Snow RW, Guerra CA, Noor AM, Myint HY, Hay SI: The global distribution of clinical episodes of Plasmodium falciparum malaria. Nature. 2005, 434: 214-217. 10.1038/nature03342.
Molineaux L, Gramiccia G: The Garki Project: Research on the Epidemiology and Control of Malaria in the Sudan Savanna of West Africa. 1980, Geneva, World Health Organization
Yamey G: Roll Back Malaria: a failing global health campaign. BMJ. 2004, 328: 1086-1087. 10.1136/bmj.328.7448.1086.
Lengeler C: Insecticide-treated bednets and curtains for preventing malaria. Cochrane Database Syst Rev. 2000, CD000363.
Alonso PL, Sacarlal J, Aponte JJ, Leach A, Macete E, Milman J, Mandomando I, Spiessens B, Guinovart C, Espasa M, Bassat Q, Aide P, Ofori-Anyinam O, Navia MM, Corachan S, Ceuppens M, Dubois MC, Demoitie MA, Dubovsky F, Menendez C, Tornieporth N, Ballou WR, Thompson R, Cohen J: Efficacy of the RTS,S/AS02A vaccine against Plasmodium falciparum infection and disease in young African children: randomised controlled trial. Lancet. 2004, 364: 1411-1420. 10.1016/S0140-6736(04)17223-1.
Bejon P, Lusingu J, Olotu A, Leach A, Lievens M, Vekemans J, Mshamu S, Lang T, Gould J, Dubois MC, Demoitie MA, Stallaert JF, Vansadia P, Carter T, Njuguna P, Awuondo KO, Malabeja A, Abdul O, Gesase S, Mturi N, Drakeley CJ, Savarese B, Villafana T, Ballou WR, Cohen J, Riley EM, Lemnge MM, Marsh K, von Seidlein L: Efficacy of RTS,S/AS01E vaccine against malaria in children 5 to 17 months of age. N Engl J Med. 2008, 359: 2521-2532. 10.1056/NEJMoa0807381.
Lusingu JP, Gesase S, Msham S, Francis F, Lemnge M, Seth M, Sembuche S, Rutta A, Minja D, Segeja MD, Bosomprah S, Cousens S, Noor R, Chilengi R, Druilhe P: Satisfactory safety and immunogenicity of MSP3 malaria vaccine candidate in Tanzanian children aged 12-24 months. Malar J. 2009, 8: 163. 10.1186/1475-2875-8-163.
Guyatt HL, Noor AM, Ochola SA, Snow RW: Use of intermittent presumptive treatment and insecticide treated bed nets by pregnant women in four Kenyan districts. Trop Med Int Health. 2004, 9: 255-261. 10.1046/j.1365-3156.2003.01193.x.
Nganda RY, Drakeley C, Reyburn H, Marchant T: Knowledge of malaria influences the use of insecticide treated nets but not intermittent presumptive treatment by pregnant women in Tanzania. Malar J. 2004, 3: 42. 10.1186/1475-2875-3-42.
Schellenberg D, Menendez C, Kahigwa E, Aponte J, Vidal J, Tanner M, Mshinda H, Alonso P: Intermittent treatment for malaria and anaemia control at time of routine vaccinations in Tanzanian infants: a randomised, placebo-controlled trial. Lancet. 2001, 357: 1471-1477. 10.1016/S0140-6736(00)04643-2.
Creasey A, Giha H, Hamad AA, El Hassan IM, Theander TG, Arnot DE: Eleven years of malaria surveillance in a Sudanese village highlights unexpected variation in individual disease susceptibility and outbreak severity. Parasitology. 2004, 129: 263-271. 10.1017/S0031182004005724.
Okiro EA, Hay SI, Gikandi PW, Sharif SK, Noor AM, Peshu N, Marsh K, Snow RW: The decline in paediatric malaria admissions on the coast of Kenya. Malar J. 2007, 6: 151. 10.1186/1475-2875-6-151.
O'Meara WP, Bejon P, Mwangi TW, Okiro EA, Peshu N, Snow RW, Newton CR, Marsh K: Effect of a fall in malaria transmission on morbidity and mortality in Kilifi, Kenya. Lancet. 2008, 372: 1555-1562. 10.1016/S0140-6736(08)61655-4.
Bhattarai A, Ali AS, Kachur SP, Martensson A, Abbas AK, Khatib R, Al Mafazy AW, Ramsan M, Rotllant G, Gerstenmaier JF, Molteni F, Abdulla S, Montgomery SM, Kaneko A, Bjorkman A: Impact of artemisinin-based combination therapy and insecticide-treated nets on malaria burden in Zanzibar. PLoS Med. 2007, 4: e309. 10.1371/journal.pmed.0040309.
Graves PM, Osgood DE, Thomson MC, Sereke K, Araia A, Zerom M, Ceccato P, Bell M, Del Corral J, Ghebreselassie S, Brantly EP, Ghebremeskel T: Effectiveness of malaria control during changing climate conditions in Eritrea, 1998-2003. Trop Med Int Health. 2008, 13: 218-228. 10.1111/j.1365-3156.2007.01993.x.
Biai S, Rodrigues A, Gomes M, Ribeiro I, Sodemann M, Alves F, Aaby P: Reduced in-hospital mortality after improved management of children under 5 years admitted to hospital with malaria: randomised trial. BMJ. 2007, 335: 862. 10.1136/bmj.39345.467813.80.
Bodker R, Akida J, Shayo D, Kisinza W, Msangeni HA, Pedersen EM, Lindsay SW: Relationship between altitude and intensity of malaria transmission in the Usambara Mountains, Tanzania. J Med Entomol. 2003, 40: 706-717. 10.1603/0022-2585-40.5.706.
Lusingu JP, Jensen AT, Vestergaard LS, Minja DT, Dalgaard MB, Gesase S, Mmbando BP, Kitua AY, Lemnge MM, Cavanagh D, Hviid L, Theander TG: Levels of plasma immunoglobulin G with specificity against the cysteine-rich interdomain regions of a semiconserved Plasmodium falciparum erythrocyte membrane protein 1, VAR4, predict protection against malarial anemia and febrile episodes. Infect Immun. 2006, 74: 2867-2875. 10.1128/IAI.74.5.2867-2875.2006.
Mmbando BP, Segeja MD, Msangeni HA, Sembuche SH, Ishengoma DS, Seth MD, Francis F, Rutta AS, Kamugisha ML, Lemnge MM: Epidemiology of malaria in an area prepared for clinical trials in Korogwe, north-eastern Tanzania. Malar J. 2009, 8: 165. 10.1186/1475-2875-8-165.
Drakeley CJ, Carneiro I, Reyburn H, Malima R, Lusingu JP, Cox J, Theander TG, Nkya WM, Lemnge MM, Riley EM: Altitude-dependent and -independent variations in Plasmodium falciparum prevalence in northeastern Tanzania. J Infect Dis. 2005, 191: 1589-1598. 10.1086/429669.
Reyburn H, Mbatia R, Drakeley C, Bruce J, Carneiro I, Olomi R, Cox J, Nkya WM, Lemnge M, Greenwood BM, Riley EM: Association of transmission intensity and age with clinical manifestations and case fatality of severe Plasmodium falciparum malaria. JAMA. 2005, 293: 1461-1470. 10.1001/jama.293.12.1461.
Massaga JJ, Kitua AY, Lemnge MM, Akida JA, Malle LN, Ronn AM, Theander TG, Bygbjerg IC: Effect of intermittent treatment with amodiaquine on anaemia and malarial fevers in infants in Tanzania: a randomised placebo-controlled trial. Lancet. 2003, 361: 1853-1860. 10.1016/S0140-6736(03)13504-0.
Schellenberg D, Menendez C, Aponte JJ, Kahigwa E, Tanner M, Mshinda H, Alonso P: Intermittent preventive antimalarial treatment for Tanzanian infants: follow-up to age 2 years of a randomised, placebo-controlled trial. Lancet. 2005, 365: 1481-1483. 10.1016/S0140-6736(05)66418-5.
Killeen GF, Smith TA, Ferguson HM, Mshinda H, Abdulla S, Lengeler C, Kachur SP: Preventing childhood malaria in Africa by protecting adults from mosquitoes with insecticide-treated nets. PLoS Med. 2007, 4: e229. 10.1371/journal.pmed.0040229.
Alifrangis M, Lemnge MM, Ronn AM, Segeja MD, Magesa SM, Khalil IF, Bygbjerg IC: Increasing prevalence of wildtypes in the dihydrofolate reductase gene of Plasmodium falciparum in an area with high levels of sulfadoxine/pyrimethamine resistance after introduction of treated bed nets. Am J Trop Med Hyg. 2003, 69: 238-243.
Gosling RD, Drakeley CJ, Mwita A, Chandramohan D: Presumptive treatment of fever cases as malaria: help or hindrance for malaria control?. Malar J. 2008, 7: 132. 10.1186/1475-2875-7-132.