Operational strategies to achieve and maintain malaria elimination.
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ABSTRACT:
SUBMITTER: Moonen B
PROVIDER: S-EPMC3037542 | biostudies-literature | 2010 Nov
REPOSITORIES: biostudies-literature
Publications
Operational strategies to achieve and maintain malaria elimination.
Moonen Bruno B Cohen Justin M JM Snow Robert W RW Slutsker Laurence L Drakeley Chris C Smith David L DL Abeyasinghe Rabindra R RR Rodriguez Mario Henry MH Maharaj Rajendra R Tanner Marcel M Targett Geoffrey G
Lancet (London, England) 20101028 9752
Present elimination strategies are based on recommendations derived during the Global Malaria Eradication Program of the 1960s. However, many countries considering elimination nowadays have high intrinsic transmission potential and, without the support of a regional campaign, have to deal with the constant threat of imported cases of the disease, emphasising the need to revisit the strategies on which contemporary elimination programmes are based. To eliminate malaria, programmes need to concent ...[more]
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Project description:Malaria elimination requires reducing both the potential of mosquitoes to transmit parasites to humans and humans to transmit parasites to mosquitoes. To achieve this goal in Southern province, Zambia a mass test and treat (MTAT) campaign was conducted from 2011-2013 to complement high coverage of long-lasting insecticide-treated nets (LLIN). To identify factors likely to increase campaign effectiveness, a modelling approach was applied to investigate the simulated effect of alternative operational strategies for parasite clearance in southern province.OpenMalaria, a discrete-time, individual-based stochastic model of malaria, was parameterized for the study area to simulate anti-malarial drug administration for interruption of transmission. Simulations were run for scenarios with a range of artemisinin-combination therapies, proportion of the population reached by the campaign, targeted age groups, time between campaign rounds, Plasmodium falciparum test protocols, and the addition of drugs aimed at preventing onward transmission. A sensitivity analysis was conducted to assess uncertainty of simulation results. Scenarios were evaluated based on the reduction in all-age parasite prevalence during the peak transmission month one year following the campaign, compared to the currently-implemented strategy of MTAT 19 % population coverage at pilot and 40 % coverage during the first year of implementation in the presence of 56 % LLIN use and 18 % indoor residual spray coverage.Simulation results suggest the most important determinant of success in reducing prevalence is the population coverage achieved in the campaign, which would require more than 1 year of campaign implementation for elimination. The inclusion of single low-dose primaquine, which acts as a gametocytocide, or ivermectin, which acts as an endectocide, to the drug regimen did not further reduce parasite prevalence one year following the campaign compared to the currently-implemented strategy. Simulation results indicate a high proportion of low-density infections were missed by rapid diagnostic tests that would be treated and cleared with mass drug administration (MDA).The optimal implementation strategy for MTAT or MDA will vary by background level of prevalence, by rate of infections imported to the area, and by ability to operationally achieve high population coverage. Overall success with new parasite clearance strategies depends on continued coverage of vector control interventions to ensure sustained gains in reduction of disease burden.
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Project description:BackgroundMalaria causes more than 200 million cases of illness and 400,000 deaths each year across 90 countries. The World Health Organization (WHO) set a goal for 35 countries to eliminate malaria by 2030, with an intermediate milestone of 10 countries by 2020. In 2017, the WHO established the Elimination-2020 (E-2020) initiative to help countries achieve their malaria elimination goals and included 21 countries with the potential to eliminate malaria by 2020.MethodsAcross its three levels of activity (country, region and global), the WHO developed normative and implementation guidance on strategies and activities to eliminate malaria; provided technical support and subnational operational assistance; convened national malaria programme managers at three global meetings to share innovations and best practices; advised countries on strengthening their strategy to prevent re-establishment and preparing for WHO malaria certification; and contributed to maintaining momentum towards elimination through periodic evaluations, monitoring and oversight of progress in the E-2020 countries. Changes in the number of indigenous cases in E-2020 countries between 2016 and 2020 are reported, along with the number of countries that eliminated malaria and received WHO certification.ResultsThe median number of indigenous cases in the E-2020 countries declined from 165.5 (interquartile range [IQR] 14.25-563.75) in 2016 to 78 (IQR 0-356) in 2020; 12 (57%) countries reported reductions in indigenous cases over that period, of which 7 (33%) interrupted malaria transmission and maintained a malaria-free status through 2020 and 4 (19%) were certified malaria-free by the WHO. Two countries experienced outbreaks of malaria in 2020 and 2021 attributed, in part, to the COVID-19 pandemic.ConclusionsAlthough the E-2020 countries contributed to the achievement of the 2020 global elimination milestone, the initiative highlights the difficulties countries face to interrupt malaria transmission, even when numbers of cases are very low. The 2025 global elimination milestone is now approaching, and the lessons learned, experience gained, and updated guidance developed during the E-2020 initiative will help serve the countries seeking to eliminate malaria by 2025.
| S-EPMC8686104 | biostudies-literature
Project description:Since 2012, the Zanzibar Malaria Elimination Program has been implementing reactive case detection (RACD). Health facility (HF) staff send individual malaria case notifications by using mobile phones, triggering a review of HF records and malaria testing and treatment at the household level by a district malaria surveillance officer. We assessed the completeness and timeliness of this system, from case notification to household-level response. We reviewed two years (2015-2016) of primary register information in 40 randomly selected HFs on Zanzibar's two islands Unguja and Pemba and database records of case notifications from all registered HFs for the period 2013-16. The operational coverage of the system was calculated as proportion of HF-registered cases that were successfully reviewed and followed up at their household. Timeliness was defined as completion of each step within 1 day. Public HFs notified almost all registered cases (91% in Unguja and 87% in Pemba), and 74% of cases registered at public HFs were successfully followed up at their household in Unguja and 79% in Pemba. Timely operational coverage (defined as each step, diagnosis to notification, notification to review, and review to household-level response, completed within 1 day) was achieved for only 25% of registered cases in Unguja and 30% in Pemba. Records and data from private HFs on Unguja indicated poor notification performance in the private sector. Although the RACD system in Zanzibar achieved high operational coverage, timeliness was suboptimal. Patients diagnosed with malaria at private HFs and hospitals appeared to be largely missed by the RACD system.
| S-EPMC7008315 | biostudies-literature
Project description:BackgroundSubstantial global progress in the control of malaria in recent years has led to increased commitment to its potential elimination. Whether this is possible in high transmission areas of sub-Saharan Africa remains unclear. Zanzibar represents a unique case study of such attempt, where modern tools and strategies for malaria treatment and vector control have been deployed since 2003.MethodsWe have studied temporal trends of comprehensive malariometric indices in two districts with over 100,000 inhabitants each. The analyses included triangulation of data from annual community-based cross-sectional surveys, health management information systems, vital registry and entomological sentinel surveys.ResultsThe interventions, with sustained high-community uptake, were temporally associated with a major malaria decline, most pronounced between 2004 and 2007 and followed by a sustained state of low transmission. In 2015, the Plasmodium falciparum community prevalence of 0.43% (95% CI 0.23-0.73) by microscopy or rapid diagnostic test represented 96% reduction compared with that in 2003. The P. falciparum and P. malariae prevalence by PCR was 1.8% (95% CI 1.3-2.3), and the annual P. falciparum incidence was estimated to 8 infections including 2.8 clinical episodes per 1000 inhabitants. The total parasite load decreased over 1000-fold (99.9%) between 2003 and 2015. The incidence of symptomatic malaria at health facilities decreased by 94% with a trend towards relatively higher incidence in age groups > 5 years, a more pronounced seasonality and with reported travel history to/from Tanzania mainland as a higher risk factor. All-cause mortality among children < 5 years decreased by 72% between 2002 and 2007 mainly following the introduction of artemisinin-based combination therapies whereas the main reduction in malaria incidence followed upon the vector control interventions from 2006. Human biting rates decreased by 98% with a major shift towards outdoor biting by Anopheles arabiensis.ConclusionsZanzibar provides new evidence of the feasibility of reaching uniquely significant and sustainable malaria reduction (pre-elimination) in a previously high endemic region in sub-Saharan Africa. The data highlight constraints of optimistic prognostic modelling studies. New challenges, mainly with outdoor transmission, a large asymptomatic parasite reservoir and imported infections, require novel tools and reoriented strategies to prevent a rebound effect and achieve elimination.
| S-EPMC6341737 | biostudies-literature
Project description:BackgroundSuccessful reduction of malaria transmission to very low levels has made Isabel Province, Solomon Islands, a target for early elimination by 2014. High malaria transmission in neighbouring provinces and the potential for local asymptomatic infections to cause malaria resurgence highlights the need for sub-national tailoring of surveillance interventions. This study contributes to a situational analysis of malaria in Isabel Province to inform an appropriate surveillance intervention.MethodsA mixed method study was carried out in Isabel Province in late 2009 and early 2010. The quantitative component was a population-based prevalence survey of 8,554 people from 129 villages, which were selected using a spatially stratified sampling approach to achieve uniform geographical coverage of populated areas. Diagnosis was initially based on Giemsa-stained blood slides followed by molecular analysis using polymerase chain reaction (PCR). Local perceptions and practices related to management of fever and treatment-seeking that would impact a surveillance intervention were also explored using qualitative research methods.ResultsApproximately 33% (8,554/26,221) of the population of Isabel Province participated in the survey. Only one subject was found to be infected with Plasmodium falciparum (Pf) (96 parasites/?L) using Giemsa-stained blood films, giving a prevalence of 0.01%. PCR analysis detected a further 13 cases, giving an estimated malaria prevalence of 0.51%. There was a wide geographical distribution of infected subjects. None reported having travelled outside Isabel Province in the previous three months suggesting low-level indigenous malaria transmission. The qualitative findings provide warning signs that the current community vigilance approach to surveillance will not be sufficient to achieve elimination. In addition, fever severity is being used by individuals as an indicator for malaria and a trigger for timely treatment-seeking and case reporting. In light of the finding of a low prevalence of parasitaemia, the current surveillance system may not be able to detect and prevent malaria resurgence.ConclusionAn adaption to the malERA surveillance framework is proposed and recommendations made for a tailored provincial-level surveillance intervention, which will be essential to achieve elimination, and to maintain this status while the rest of the country catches up.
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Project description:Importance:Achievement of the World Health Organization (WHO) target of eliminating hepatitis C virus (HCV) by 2030 will require an increase in key services, including harm reduction, HCV screening, and HCV treatment initiatives in member countries. These data are not available for Canada but are important for informing a national HCV elimination strategy. Objective:To use a decision analytical model to explore the association of different treatment strategies with HCV epidemiology and HCV-associated mortality in Canada and to assess the levels of service increase needed to meet the WHO elimination targets by 2030. Design, Setting, and Participants:Study participants in this decision analytical model included individuals with hepatitis C virus infection in Canada. Five HCV treatment scenarios (optimistic, very aggressive, aggressive, gradual decrease, and rapid decrease) were applied using a previously validated Markov-type mathematical model. The optimistic and very aggressive treatment scenarios modeled a sustained annual treatment of 10 200 persons and 14 000 persons, respectively, from 2018 to 2030. The aggressive, gradual decrease, and rapid decrease scenarios assessed decreases in treatment uptake from 14 000 persons to 10 000 persons per year, 12 000 persons to 8500 persons per year, and 12 000 persons to 4500 persons per year, respectively, between 2018 and 2030. Main Outcomes and Measures:Hepatitis C virus prevalence and HCV-associated health outcomes were assessed for each of the 5 treatment scenarios with the goal of identifying strategies to achieve HCV elimination by 2030. Results:An estimated mean 180 142 persons (95% CI, 122 786-196 862 persons) in Canada had chronic HCV infection at the end of 2017. The optimistic and gradual decrease scenarios estimated a decrease in HCV prevalence from 180 142 persons to 37 246 persons and 37 721 persons, respectively, by 2030. Relative to 2015, this decrease in HCV prevalence was associated with 74%, 69%, and 69% reductions in the prevalence of decompensated cirrhosis, hepatocellular carcinoma, and liver-associated mortality, respectively, leading to HCV elimination by 2030. More aggressive treatment uptake (very aggressive scenario) could result in goal achievement up to 3 years earlier than 2030, although a rapid decrease in the initiation of treatment (rapid decrease scenario) would preclude Canada from reaching the HCV elimination goal by 2030. Conclusions and Relevance:The study findings suggest that Canada could meet the WHO goals for HCV elimination by 2030 by sustaining the current national HCV treatment rate during the next decade. This target will not be achieved if treatment uptake is allowed to decrease rapidly.
| S-EPMC7203608 | biostudies-literature
Project description:Historic levels of funding have reduced the global burden of malaria in recent years. Questions remain, however, as to whether scaling up interventions, in parallel with economic growth, has made malaria elimination more likely today than previously. The consequences of "trying but failing" to eliminate malaria are also uncertain. Reduced malaria exposure decreases the acquisition of semi-immunity during childhood, a necessary phase of the immunological transition that occurs on the pathway to malaria elimination. During this transitional period, the risk of malaria resurgence increases as proportionately more individuals across all age-groups are less able to manage infections by immune response alone. We developed a robust model that integrates the effects of malaria transmission, demography, and macroeconomics in the context of Plasmodium falciparum malaria within a hyperendemic environment. We analyzed the potential for existing interventions, alongside economic development, to achieve malaria elimination. Simulation results indicate that a 2% increase in future economic growth will increase the US$5.1 billion cumulative economic burden of malaria in Ghana to US$7.2 billion, although increasing regional insecticide-treated net coverage rates by 25% will lower malaria reproduction numbers by just 9%, reduce population-wide morbidity by -0.1%, and reduce prevalence from 54% to 46% by 2034. As scaling up current malaria control tools, combined with economic growth, will be insufficient to interrupt malaria transmission in Ghana, high levels of malaria control should be maintained and investment in research and development should be increased to maintain the gains of the past decade and to minimize the risk of resurgence, as transmission drops.
| S-EPMC7646798 | biostudies-literature
Project description:Large reductions in the global malaria burden have been achieved, but plateauing funding poses a challenge for progressing towards the ultimate goal of malaria eradication. Using previously published mathematical models of Plasmodium falciparum and Plasmodium vivax transmission incorporating insecticide-treated nets (ITNs) as an illustrative intervention, we sought to identify the global funding allocation that maximized impact under defined objectives and across a range of global funding budgets. The optimal strategy for case reduction mirrored an allocation framework that prioritizes funding for high-transmission settings, resulting in total case reductions of 76% and 66% at intermediate budget levels, respectively. Allocation strategies that had the greatest impact on case reductions were associated with lesser near-term impacts on the global population at risk. The optimal funding distribution prioritized high ITN coverage in high-transmission settings endemic for P. falciparum only, while maintaining lower levels in low-transmission settings. However, at high budgets, 62% of funding was targeted to low-transmission settings co-endemic for P. falciparum and P. vivax. These results support current global strategies to prioritize funding to high-burden P. falciparum-endemic settings in sub-Saharan Africa to minimize clinical malaria burden and progress towards elimination, but highlight a trade-off with 'shrinking the map' through a focus on near-elimination settings and addressing the burden of P. vivax.
| S-EPMC10957170 | biostudies-literature
Project description:BackgroundMining in the Amazon exposes gold miners to various diseases, including malaria, whose control is still a major challenge. The environment of the mines contributes to the proliferation of vector mosquitoes and the precarious housing conditions facilitate transmission of the disease. Understanding gold miners' perceptions is essential for the formulation of strategies to fight malaria. A qualitative study was carried out in the municipality of Calçoene, state of Amapá, Brazilian Amazon adjointining the municipality of Oiapoque, that is in the border area with French Guiana and Suriname.MethodsA semi-structured interview was applied to an intentional sample of 29 miners, a number determined by the theoretical saturation criterion. Thematic analysis was adopted to obtain the results and the Cohen's Kappa index was calculated to verify the agreement between observers during coding.ResultsThe agreement between observers was verified by a Cohen's Kappa index of 0.82. Analysis of the interviews showed that gold miners were subjected to prejudice from the community due to forest diseases that they can transmit, and their activities are often associated with crime. When the miners return to their hometown after a period of mining, the urban population blames them for the onset of diseases such as malaria. Most participants in the survey did not know how malaria transmission occurs, and associated its occurrence with contaminated water and food. Participants reported not being afraid of the disease, trusting the diagnosis and available treatment, though this depends on where they are treated. The use of therapeutic resources, such as medicinal plants and medicines acquired in the illegal market, is very common in this population. Despite the challenges identified by the research subjects, they believe that the disease can be controlled, or the cases reduced, but there was low acceptability for a possible mass drug administration (MDA) intervention.ConclusionDespite a recent reduction in malaria prevalence in Brazil, there are still vulnerable populations, such as gold miners, who help to perpetuate the existence of the disease in the Amazon. The lack of knowledge regarding how the transmission of malaria occurs, associated with myths regarding this and the use of traditional health practices and illegal drugs for the treatment of the disease without a specific diagnosis, jeopardizes the country's efforts to eliminate malaria. It is necessary to implement control programmes in these populations, especially those who frequently travel around the border region and to remote locations, which are difficult regions for health teams to access, thus hindering diagnostic and treatment actions. For this reason, understanding the perceptions of these individuals as well as their customs, beliefs and lifestyle, can assist in the production of targeted educational material and adoption of strategies in the elimination of malaria in the country.
| S-EPMC8236171 | biostudies-literature