Towards malaria elimination in Brazil
Authors: Gabriel Z Laporta
Journal: The Lancet Global Health (2024)

Malaria poses a distinct challenge on every continent, but there is a shared goal of global elimination, often referred to as the global technical strategy for malaria by WHO.1WHOGlobal technical strategy for malaria 2016–2030, 2021 update. World Health Organization, Geneva2021who.int/publications/i/item/9789240031357Date accessed: November 23, 2023Google Scholar Plasmodium falciparum is the causative agent of malaria showing the highest case–fatality ratio, but the prevalence of Plasmodium vivax malaria has hindered progress in the ongoing efforts to eliminate malaria in the southern regions of the Americas. This is true for Brazil, where, in The Lancet Global Health, Marcus Lacerda and colleagues2Brito M Rufatto R Murta F et al.Operational feasibility of Plasmodium vivax radical cure with tafenoquine or primaquine following point-of-care, quantitative glucose-6-phosphate dehydrogenase testing in the Brazilian Amazon: a real-life retrospective analysis.Lancet Glob Health. 2024; 12: e467-e477Google Scholar show the operational feasibility of and the high adherence to the novel treatment algorithm of using point-of-care, quantitative, glucose-6-phosphate dehydrogenase (G6PD) testing before administering tafenoquine within the Brazilian health system. This trial enrolled 6075 patients with confirmed vivax malaria across 43 health facilities in Manaus and Porto Velho, serving as a real-life experiment.2Brito M Rufatto R Murta F et al.Operational feasibility of Plasmodium vivax radical cure with tafenoquine or primaquine following point-of-care, quantitative glucose-6-phosphate dehydrogenase testing in the Brazilian Amazon: a real-life retrospective analysis.Lancet Glob Health. 2024; 12: e467-e477Google Scholar This study represents a potential paradigm shift for the treatment of vivax malaria, signifying a fundamental shift with potential far-reaching consequences for malaria elimination in Brazil and beyond. The new treatment with tafenoquine is more efficient in curing P vivax, offering an equivalent likelihood of cure as the current 7-day or 14-day standard primaquine treatments in Brazil but administered in a single-day regimen.3Lacerda MVG Llanos-Cuentas A Krudsood S et al.Single-dose tafenoquine to prevent relapse of Plasmodium vivax malaria.N Engl J Med. 2019; 380: 215-228Crossref PubMed Scopus (164) Google Scholar, 4Llanos-Cuentas A Lacerda MVG Hien TT et al.Tafenoquine versus primaquine to prevent relapse of Plasmodium vivax Malaria.N Engl J Med. 2019; 380: 229-241Crossref PubMed Scopus (137) Google Scholar Tafenoquine use is safe, as evidenced by a similar decline in haemoglobin concentrations among patients with normal G6PD enzyme activity compared with that of primaquine use.3Lacerda MVG Llanos-Cuentas A Krudsood S et al.Single-dose tafenoquine to prevent relapse of Plasmodium vivax malaria.N Engl J Med. 2019; 380: 215-228Crossref PubMed Scopus (164) Google Scholar, 4Llanos-Cuentas A Lacerda MVG Hien TT et al.Tafenoquine versus primaquine to prevent relapse of Plasmodium vivax Malaria.N Engl J Med. 2019; 380: 229-241Crossref PubMed Scopus (137) Google Scholar Notably, all patients in the trial willingly underwent G6PD testing before initiating tafenoquine treatment.2Brito M Rufatto R Murta F et al.Operational feasibility of Plasmodium vivax radical cure with tafenoquine or primaquine following point-of-care, quantitative glucose-6-phosphate dehydrogenase testing in the Brazilian Amazon: a real-life retrospective analysis.Lancet Glob Health. 2024; 12: e467-e477Google Scholar These patients were sampled not only within the city but also in rural areas and other hard-to-reach communities, including Indigenous peoples.2Brito M Rufatto R Murta F et al.Operational feasibility of Plasmodium vivax radical cure with tafenoquine or primaquine following point-of-care, quantitative glucose-6-phosphate dehydrogenase testing in the Brazilian Amazon: a real-life retrospective analysis.Lancet Glob Health. 2024; 12: e467-e477Google Scholar We have analysed the prospect of Brazil attaining malaria-free status in the near future.5Laporta GZ Grillet ME Rodovalho SR Massad E Sallum MAM Reaching the malaria elimination goal in Brazil: a spatial analysis and time-series study.Infect Dis Poverty. 2022; 11: 39Crossref PubMed Scopus (3) Google Scholar Our forecast indicates a 46% reduction in cases by 2030, falling short of the WHO target of a 90% reduction in malaria incidence by 2030.5Laporta GZ Grillet ME Rodovalho SR Massad E Sallum MAM Reaching the malaria elimination goal in Brazil: a spatial analysis and time-series study.Infect Dis Poverty. 2022; 11: 39Crossref PubMed Scopus (3) Google Scholar We believe elimination of malaria by 2035 requires novel viable tools to combat vivax malaria and heightened political commitment to design effective interventions for malaria elimination in endemic areas.5Laporta GZ Grillet ME Rodovalho SR Massad E Sallum MAM Reaching the malaria elimination goal in Brazil: a spatial analysis and time-series study.Infect Dis Poverty. 2022; 11: 39Crossref PubMed Scopus (3) Google Scholar The new tafenoquine treatment presents a technological breakthrough for reducing vivax malaria transmission and morbidity.6Melo JO Padilha MAO Barbosa RTA Alonso WJ Vittor AY Laporta GZ Evaluation of the malaria elimination policy in Brazil: a systematic review and epidemiological analysis study.Trop Biomed. 2020; 37: 513-535PubMed Google Scholar The challenges posed by eliminating malaria in hard-to-reach communities (eg, Indigenous populations) and asymptomatic malaria carriers are the largest barriers to malaria elimination.7Ferreira MU Corder RM Johansen IC et al.Relative contribution of low-density and asymptomatic infections to Plasmodium vivax transmission in the Amazon: pooled analysis of individual participant data from population-based cross-sectional surveys.Lancet Reg Health Am. 2022; 9100169 PubMed Google Scholar Prolonged exposure to the parasite and inadequate adherence to the 7-day or 14-day standard treatments can lead to the emergence of asymptomatic malaria carriers.8Corder RM Arez AP Ferreira MU Individual variation in Plasmodium vivax malaria risk: are repeatedly infected people just unlucky?.PLoS Negl Trop Dis. 2023; 17e0011020 Crossref PubMed Scopus (1) Google Scholar Consequently, asymptomatic carriers of P vivax serve as a source for transmitting the parasite to mosquitoes.8Corder RM Arez AP Ferreira MU Individual variation in Plasmodium vivax malaria risk: are repeatedly infected people just unlucky?.PLoS Negl Trop Dis. 2023; 17e0011020 Crossref PubMed Scopus (1) Google Scholar, 9Sallum MAM Conn JE Bergo ES et al.Vector competence, vectorial capacity of Nyssorhynchus darlingi and the basic reproduction number of Plasmodium vivax in agricultural settlements in the Amazonian Region of Brazil.Malar J. 2019; 18: 117Crossref PubMed Scopus (28) Google Scholar We have assessed the vectorial capacity and vector competence of the primary malaria vector in Brazil, Nyssorhynchus darlingi, along with the P vivax reproduction number, across various communities in the Amazon region.9Sallum MAM Conn JE Bergo ES et al.Vector competence, vectorial capacity of Nyssorhynchus darlingi and the basic reproduction number of Plasmodium vivax in agricultural settlements in the Amazonian Region of Brazil.Malar J. 2019; 18: 117Crossref PubMed Scopus (28) Google Scholar We calculated the vivax malaria reproduction number to be 58·7 in the Old Rooster Rural Settlement in the municipality of Machadinho D'Oeste (Rondônia state).9Sallum MAM Conn JE Bergo ES et al.Vector competence, vectorial capacity of Nyssorhynchus darlingi and the basic reproduction number of Plasmodium vivax in agricultural settlements in the Amazonian Region of Brazil.Malar J. 2019; 18: 117Crossref PubMed Scopus (28) Google Scholar This finding implies a single vivax malaria carrier has the potential to infect mosquitoes, leading to 58 novel infections in other humans. N darlingi showed a vectorial capacity as high as 1·5—implying that, on average, at least one vivax-infectious bite per day was occurring for each infected person in this settlement in 2015.9Sallum MAM Conn JE Bergo ES et al.Vector competence, vectorial capacity of Nyssorhynchus darlingi and the basic reproduction number of Plasmodium vivax in agricultural settlements in the Amazonian Region of Brazil.Malar J. 2019; 18: 117Crossref PubMed Scopus (28) Google Scholar The proposed tafenoquine treatment has the potential to substantially reduce the number of asymptomatic carriers, infected mosquitoes, and the P vivax reproduction number in rural and isolated communities. Why is tafenoquine not a perfect drug for Brazil's malaria elimination? Political commitment to malaria elimination in Brazil is inconsistent, if not erratic. The internationally acclaimed health surveillance programme in Brazil has successfully controlled malaria and reduced mortality.5Laporta GZ Grillet ME Rodovalho SR Massad E Sallum MAM Reaching the malaria elimination goal in Brazil: a spatial analysis and time-series study.Infect Dis Poverty. 2022; 11: 39Crossref PubMed Scopus (3) Google Scholar, 6Melo JO Padilha MAO Barbosa RTA Alonso WJ Vittor AY Laporta GZ Evaluation of the malaria elimination policy in Brazil: a systematic review and epidemiological analysis study.Trop Biomed. 2020; 37: 513-535PubMed Google Scholar The number of new malaria cases in Brazil decreased by 53% from 2009 to 2020.5Laporta GZ Grillet ME Rodovalho SR Massad E Sallum MAM Reaching the malaria elimination goal in Brazil: a spatial analysis and time-series study.Infect Dis Poverty. 2022; 11: 39Crossref PubMed Scopus (3) Google Scholar Despite this, the reversal in the declining trend after 2017 reflect instabilities, including an economic crisis, austerity measures, and other health emergencies.5Laporta GZ Grillet ME Rodovalho SR Massad E Sallum MAM Reaching the malaria elimination goal in Brazil: a spatial analysis and time-series study.Infect Dis Poverty. 2022; 11: 39Crossref PubMed Scopus (3) Google Scholar, 10Castro MC Peterka C Malaria is increasing in Indigenous and artisanal mining areas in the Brazilian Amazon.Nat Med. 2023; 29: 762-764Crossref PubMed Scopus (3) Google Scholar These factors affect attention and efforts towards the organisation of health services for diagnosis and treatment.10Castro MC Peterka C Malaria is increasing in Indigenous and artisanal mining areas in the Brazilian Amazon.Nat Med. 2023; 29: 762-764Crossref PubMed Scopus (3) Google Scholar Another underlying factor is the recent surge of right-wing extremism in Brazil, which directly jeopardises addressing public issues, including forest conservation, indigenous rights, and health inequalities.10Castro MC Peterka C Malaria is increasing in Indigenous and artisanal mining areas in the Brazilian Amazon.Nat Med. 2023; 29: 762-764Crossref PubMed Scopus (3) Google Scholar During Jair Bolsonaro's presidency from 2019 to 2022, the leadership of the Brazilian Ministry of Health faced internal challenges, which affected all disease control and elimination programmes.10Castro MC Peterka C Malaria is increasing in Indigenous and artisanal mining areas in the Brazilian Amazon.Nat Med. 2023; 29: 762-764Crossref PubMed Scopus (3) Google Scholar At the end of 2022, President Luiz Inácio Lula da Silva won a closely contested presidential election. The transition to a more inclusive and representative Government from a far-right one holds significant implications to secure sustained financial commitment for the effective and timely fight against malaria, albeit for the duration of its tenure. I declare no competing interests. Operational feasibility of Plasmodium vivax radical cure with tafenoquine or primaquine following point-of-care, quantitative glucose-6-phosphate dehydrogenase testing in the Brazilian Amazon: a real-life retrospective analysisQuantitative G6PD testing before tafenoquine administration was operationally feasible, with high adherence to the treatment algorithm, supporting deployment throughout the Brazilian health system. Full-Text PDF Open Access