Factors Associated with the Rapid and Durable Decline in Malaria Incidence in El Salvador, 1980-2017

Quantifying the impact of interventions against Plasmodium vivax: A model for country-specific use

In order to evaluate the impact of various intervention strategies on Plasmodium vivax dynamics in low endemicity settings without significant seasonal pattern, we introduce a simple mathematical model that can be easily adapted to reported case numbers similar to that collected by surveillance systems in various countries. The model includes case management, vector control, mass drug administration and reactive case detection interventions and is implemented in both deterministic and stochastic frameworks. It is available as an R package to enable users to calibrate and simulate it with their own data. Although we only illustrate its use on fictitious data, by simulating and comparing the impact of various intervention combinations on malaria risk and burden, this model could be a useful tool for strategic planning, implementation and resource mobilization.

Spatial patterns and climate drivers of malaria in three border areas of Brazil, Venezuela and Guyana, 2016-2018

In 2020, 77% of malaria cases in the Americas were concentrated in Venezuela, Brazil, and Colombia. These countries are characterized by a heterogeneous malaria landscape and malaria hotspots. Furthermore, the political unrest in Venezuela has led to significant cross-border population movement. Hence, the aim of this study was to describe spatial patterns and identify significant climatic drivers of malaria transmission along the Venezuela-Brazil-Guyana border, focusing on Bolivar state, Venezuela and Roraima state, Brazil. Malaria case data, stratified by species from 2016 to 2018, were obtained from the Brazilian Malaria Epidemiology Surveillance Information System, the Guyana Vector Borne Diseases Program, the Venezuelan Ministry of Health, and civil society organizations. Spatial autocorrelation in malaria incidence was explored using Getis-Ord (Gi*) statistics. A Poisson regression model was developed with a conditional autoregressive prior structure and posterior parameters were estimated using the Bayesian Markov chain Monte Carlo simulation with Gibbs sampling. There were 685,498 malaria cases during the study period. Plasmodium vivax was the predominant species (71.7%, 490,861). Malaria hotspots were located in eight municipalities along the Venezuela and Guyana international borders with Brazil. Plasmodium falciparum increased by 2.6% (95% credible interval [CrI] 2.1%, 2.8%) for one meter increase in altitude, decreased by 1.6% (95% CrI 1.5%, 2.3%) and 0.9% (95% CrI 0.7%, 2.4%) per 1 cm increase in 6-month lagged precipitation and each 1 °C increase of minimum temperature without lag. Each 1 °C increase of 1-month lagged maximum temperature increased P. falciparum by 0.6% (95% CrI 0.4%, 1.9%). P. vivax cases increased by 1.5% (95% CrI 1.3%, 1.6%) for one meter increase in altitude and decreased by  1.1% (95% CrI 1.0%, 1.2%) and 7.3% (95% CrI 6.7%, 9.7%) for each 1 cm increase of precipitation lagged at 6-months and 1 °C increase in minimum temperature lagged at 6-months. Each 1°C increase of two-month lagged maximum temperature increased P. vivax by 1.5% (95% CrI 0.6%, 7.1%). There was no significant residual spatial clustering after accounting for climatic covariates. Malaria hotspots were located along the Venezuela and Guyana international border with Roraima state, Brazil. In addition to population movement, climatic variables were important drivers of malaria transmission in these areas.

Financing malaria

The faltering of progress towards malaria elimination follows a plateauing in international financing since 2010. Despite calls for increased international financing, this will be hard to achieve. Both developed country donors and developing countries with malaria face severe fiscal constraints in expanding malaria funding in the next few years. Simply exhorting countries to spend more is unlikely to be successful, just as the Abuja declaration was not, and the developing countries with most malaria burden suffer from weaker economic growth and less capacity to increase domestic financing. One major prospect for substantial new financing is China, but this may depend on established funders yielding influence in the global financing architecture to China and other emerging economies. This argues for greater emphasis on spending available financing better, but improving the impact of international funding is not straightforward. It is associated with significant transaction costs for recipients, impairs the ability of the WHO to coordinate global efforts, and may pressure recipient countries to focus more on commodities and easy wins instead of investing in health systems and management capacity. While more should be done to mitigate these perverse effects, much of this is the unavoidable price of such generosity and the inevitable need for accountability to funders. Ultimately, countries must do more with their own spending, which is often under-counted, but usually far exceeds the international contribution. The experience of Sri Lanka, El Salvador, and China-three countries that eliminated malaria-provides two pointers. First, achieving early and widespread treatment of most malaria cases, which is not the case in much of high burden Africa, may be critical to sustain accelerated elimination. Second, such coverage requires health systems that prioritize access for all services and conditions. Public opinion surveys indicate that this is consistent with what much of the affected population wants, prioritizes, and is willing to finance through higher taxes, which points to weaknesses in accountability of policy to people. International funders could do better to heed what affected populations want and let local partners be responsive to their own public's preferences.

What India can learn from globally successful malaria elimination programmes

India is targeting malaria elimination by 2030. Understanding and adopting the strategies employed by countries that have successfully eliminated malaria can serve as a crucial thrust in this direction for a geographically diverse country like India. This analysis is based on extensive literature search on malaria elimination policies, strategies and programmes adopted by nine countries (China, El Salvador, Algeria, Argentina, Uzbekistan, Paraguay, Sri Lanka, Maldives and Armenia) which have attained malaria-free status over the past decade. The key points which India can learn from their journey are mandatory time-bound response in the form of case reporting and management, rapid vector control response, continuous epidemiological and entomological surveillance, elevated community participation, more training and capacity building, private sector involvement, use of quality diagnostics, cross-border collaborations, inclusion of prevention of re-establishment programmes into the elimination plans, higher investment in research, and uninterrupted funds for successful implementation of malaria elimination programmes. These learnings would help India and other South Asian countries steer their programmes by devising tailor-made strategies for their own regions.

Rethinking human resources and capacity building needs for malaria control and elimination in Africa

Despite considerable success in controlling malaria worldwide, progress toward achieving malaria elimination has largely stalled. In particular, strategies to overcome roadblocks in malaria control and elimination in Africa are critical to achieving worldwide malaria elimination goals-this continent carries 94% of the global malaria case burden. To identify key areas for targeted efforts, we combined a comprehensive review of current literature with direct feedback gathered from frontline malaria workers, leaders, and scholars from Africa. Our analysis identified deficiencies in human resources, training, and capacity building at all levels, from research and development to community involvement. Addressing these needs will require active and coordinated engagement of stakeholders as well as implementation of effective strategies, with malaria-endemic countries owning the relevant processes. This paper reports those valuable identified needs and their concomitant opportunities to accelerate progress toward the goals of the World Health Organization's Global Technical Strategy for Malaria 2016-2030. Ultimately, we underscore the critical need to re-think current approaches and expand concerted efforts toward increasing relevant human resources for health and capacity building at all levels if we are to develop the relevant competencies necessary to maintain current gains while accelerating momentum toward malaria control and elimination.

Evaluating Vertical Malaria Community Health Worker Programs as Malaria Declines: Learning From Program Evaluations in Honduras and Lao PDR

Community case management by community health workers has substantially reduced malaria across the Greater Mekong Subregion and Central America. To sustain current and achieve further reductions in malaria, surveillance and delivery platforms must be redesigned to ensure their continued use by key populations.

Background:

Across the Greater Mekong Subregion (GMS) and Central America, governments commonly employ community health workers (CHWs) to improve access to and uptake of malaria services. Many of these networks are vertical in design, organized to extend malaria-only services to those remaining communities in which malaria persists.

Methods:

Between 2019 and 2020, national ministries of health (MOH) and Clinton Health Access Initiative conducted mixed-methods CHW program evaluations across the GMS and Central America. Routine surveillance and programmatic data were analyzed to quantify CHW contributions to malaria elimination objectives and identify gaps and challenges. Semistructured interviews were conducted with governmental and nongovernmental stakeholders from central to community level. This article draws comparisons between the Lao People's Democratic Republic (PDR) and Honduras CHW program evaluation results to distill broader hypotheses about how vertical CHW programs might evolve as their primary mission nears its end.

Results:

CHWs contribute substantially to malaria case detection and surveillance, diagnosing and treating 27% of malaria cases in Lao PDR and 55% in the department of Gracias a Dios, Honduras in 2019. In the same year, malaria test positivity neared less than 1% in both countries. In 2019, 80% of CHWs in Lao PDR and 74% in Gracias a Dios, Honduras did not report a single malaria case. From inception, both programs were organized as vertical (malaria-only) CHW programs reliant upon Global Fund financing for malaria commodities, training, supervision and, where applicable, remuneration.

Conclusions:

Although community case management by CHWs has been highly impactful in reducing malaria cases to near zero, new challenges of acceptability and effectiveness of malaria-only service delivery, feasibility of continued vertical program management, and sustainable financing have emerged. To achieve and sustain reductions in malaria, surveillance and delivery platforms must be redesigned to encourage (and reward) care seeking based on experience of symptoms and not on a patient or caregiver's presumptive diagnosis of disease. By expanding the roles and responsibilities of currently vertical malaria CHWs, malarial interventions can be optimized and sustained. Such a shift will also position existing community-based platforms to be resilient and responsive as epidemiology of disease and community need shift.

Cross-border malaria in Northern Brazil

BACKGROUND

Cross-border malaria is a major barrier to elimination efforts. Along the Venezuela-Brazil-Guyana border, intense human mobility fueled primarily by a humanitarian crisis and illegal gold mining activities has increased the occurrence of cross-border cases in Brazil. Roraima, a Brazilian state situated between Venezuela and Guyana, bears the greatest burden. This study analyses the current cross-border malaria epidemiology in Northern Brazil between the years 2007 and 2018.

METHODS

De-identified data on reported malaria cases in Brazil were obtained from the Malaria Epidemiological Surveillance Information System for the years 2007 to 2018. Pearson's Chi-Square test of differences was utilized to assess differences between characteristics of cross-border cases originating from Venezuela and Guyana, and between border and transnational cases. A logistic regression model was used to predict imported status of cases.

RESULTS

Cross-border cases from Venezuela and Guyana made up the majority of border and transnational cases since 2012, and Roraima remained the largest receiving state for cross-border cases over this period. There were significant differences in the profiles of border and transnational cases originating from Venezuela and Guyana, including type of movement and nationality of patients. Logistic regression results demonstrated Venezuelan and Guyanese nationals, Brazilian miners, males, and individuals of working age had heightened odds of being an imported case. Furthermore, Venezuelan citizens had heightened odds of seeking care in municipalities adjacent Venezuela, rather than transnational municipalities.

CONCLUSIONS

Cross-border malaria contributes to the malaria burden at the Venezuela-Guyana-Brazil border. The identification of distinct profiles of case importation provides evidence on the need to strengthen surveillance at border areas, and to deploy tailored strategies that recognize different mobility routes, such as the movement of refuge-seeking individuals and of Brazilians working in mining.

Long-term transmission patterns and public health policies leading to malaria elimination in Panamá

Background

The present study provides a countrywide perspective of the malaria situation in Panamá over a long-term framework, with the purpose of identifying historical malaria resurgence events and their potential causes.

Methods

A descriptive-ecological study was conducted by analysing demographic and epidemiological annual malaria time series data in Panamá (1884–2019) using several data sources. Malaria intensity indicators were calculated during the study period. The effects of El Niño Southern Oscillation on malaria transmission were also analysed using a retrospective analysis of malaria cases between 1957 and 2019.

Results

Several factors were identified responsible for malaria resurgence in Panamá, mostly related with Malaria Control Programme weakening. During the past 20 years (2000–2019) malaria has progressively increased in prevalence within indigenous settlements, with a predominance of male cases and a high proportion (15% of total cases) in children less than 5 years old. During this period, a significant and increasing proportion of the Plasmodium falciparum cases were imported. Retrospective analysis (1957–2019) evidenced that ENSO had a significant impact on malaria transmission dynamics in Panamá.

Conclusions

Data analysis confirmed that although authorities have been successful in focalizing malaria transmission in the country, there are still neglected issues to be solved and important intercultural barriers that need to be addressed in order to achieve elimination of the disease by 2022. This information will be useful for targeting strategies by the National Malaria Elimination Programme.

Health policy impacts on malaria transmission in Costa Rica

Costa Rica is near malaria elimination. This achievement has followed shifts in malaria health policy. Here, we evaluate the impacts that different health policies have had on malaria transmission in Costa Rica from 1913 to 2018. We identified regime shifts and used regression models to measure the impact of different health policies on malaria transmission in Costa Rica using annual case records. We found that vector control and prophylactic treatments were associated with a 50% malaria case reduction in 1929-1931 compared with 1913-1928. DDT introduction in 1946 was associated with an increase in annual malaria case reduction from 7.6% (1942-1946) to 26.4% (1947-1952). The 2006 introduction of 7-day supervised chloroquine and primaquine treatments was the most effective health policy between 1957 and 2018, reducing annual malaria cases by 98% (2009-2018) when compared with 1957-1968. We also found that effective malaria reduction policies have been sensitive to natural catastrophes and extreme climatic events, both of which have increased malaria transmission in Costa Rica. Currently, outbreaks follow malaria importation into vulnerable areas of Costa Rica. This highlights the need to timely diagnose and treat malaria, while improving living standards, in the affected areas.