Posts or Comments 07 March 2021

Monthly Archive for "September 2015"

Borders &Diagnosis &Epidemiology &ITNs Bill Brieger | 30 Sep 2015

Individual and Household Level Risk Factors Associated with Malaria in Mutasa District, Zimbabwe: a Serial Cross-Sectional Study

Mufaro Kanyangarara and her PhD thesis adviser, Luke Mullany of the Johns Hopkins Bloomberg School of Public Health Department of International Health, have been looking into the challenges of controlling and eventually eliminating malaria in a multi-country context in southern Africa. We are sharing abstracts from her pioneering work including the following which explores risk factors on the Zimbabwe-Mozambique order.

Background: Malaria constitutes a major public health problem in Zimbabwe, particularly in theMAP 2000 and 2015 S Africa north and east bordering Zambia and Mozambique. In Manicaland Province in eastern Zimbabwe, malaria transmission is seasonal and unstable. As a result of intensive scale up of malaria interventions, malaria control was successful in Manicaland Province. However, over the past decade, Manicaland Province has reported increased malaria transmission, and the resurgence of malaria in this region has been attributed to limited funding, drug resistance and insecticide resistance. One of the worst affected districts is Mutasa District. The aim of the study was to identify malaria risk factors at the individual and household levels to better understand what is driving factors associated with malaria and consequently enhance malaria control in eastern Zimbabwe.

Methods: Between October 2012 and September 2014, individual demographic data and household characteristics were collected from cross-sectional surveys of 1,116 individuals residing in 316 households in Mutasa District. Factors characterizing the surrounding environment were obtained from remote sensing data. Factors associated with malaria (measured by rapid diagnostic test [RDT]) were identified through univariate and multivariate multilevel logistic regression models.

Results: A total of 74 (6.4%) participants were RDT positive. Parasite prevalence differed by season (10.4% rainy and 2.9% dry, OR 4.52, 95% CI 2.11-9.69). Sleeping under a bednet showed a protective effect against malaria (OR 0.54, 95% CI 0.29-1.00) despite pyrethroid resistance. The household level risk factors protective against malaria were household density (OR 0.89, 95% CI 0.87-0.97) and increasing distance from the border with Mozambique (OR 0.86, 95% CI 0.76-0.97). Increased malaria risk was associated with recent indoor residual spraying (OR 2.30, 95% CI 1.16-4.56).

Conclusions: Malaria risk was concentrated in areas located at a lower household density and in closer proximity to the Mozambique border. Malaria control in these “high risk” areas may need to be enhanced. These findings underscore the need for strong cross-border malaria control initiatives to complement country specific interventions.

Elimination Bill Brieger | 29 Sep 2015

Are we ready to actively support malaria elimination?

As Michael Gerson of the Washington Post said today, “It is now possible to set goals in a number of areas — malaria elimination, an AIDS-free generation, the end of extreme poverty — and not be dismissed as a crank.” He was lamenting the fact that with the 17 new Sustainable Development Goals there are 169 targets – too much to get a handle on. Thus focus on something specific like malaria elimination is important for endemic countries to consider.

The New York Times reports that, “Now, the United Nations and the Bill and Melinda Gates Foundation are calling on the world to eradicate the disease by 2040, potentially saving 11 million lives in the next 25 years. They say this goal can be achieved for between $90 billion and $120 billion and would produce economic benefits of $2 trillion.” Even though some experts may question the feasibility of 2040, they are no longer calling Gates a crank.

2000-2015The challenge has been though that our global malaria programming is largely stuck in the era of scale up of control efforts with a focus on getting more long lasting insecticide-treated nets and increased household spraying out in high burden areas. As recent reports from WHO and partners indicate, the malaria morbidity and mortality map is shrinking, but there do remain high burden areas. It is only that now we need to focus equally on the science and management of the tools needed to eliminate the disease.

The challenges lie in issues like weak health systems and increasing resistance of parasites and vectors to existing tools. These problems can be overcome through research if the international community is willing to provide the funding.

Here is where groups like the Malaria Eradication Scientific Alliance (MESA) come in. They are addressing the following:

  • Basic science and enabling technologies
  • Insecticide and drug resistance
  • Characterizing the reservoir and measuring transmission
  • Specific Tools for elimination
  • Combining interventions and modelling
  • Health systems and policy research

Major donors like the US President’s Malaria Initiative, The Global Fund to fight AIDS, TB and Malaria and the World Bank need to join with groups like MESA and the Gates Foundation and get behind this agenda. Countries, when updating their malaria strategic plans for new funding from the Global Fund, need to be encouraged to include malaria elimination efforts. Opportunities are should not be missed on the frontline in southern Africa including Zimbabwe, Zambia, Angola, Mozambique, Botswana, South Africa, Swaziland and Namibia to study and implement new approaches and document the lessons, which could also be picked up in the countries of the Sahel, the Pacific Islands and South America. Malaria will not eliminate itself!

Borders &Elimination &Resistance &Surveillance Bill Brieger | 29 Sep 2015

Epidemiology of Resurgent Malaria in Eastern Zimbabwe: Risk Factors, Spatio-Temporal Patterns and Prospects for Regaining Malaria Control

Mufaro Kanyangarara and her PhD thesis adviser, Luke Mullany, of the Johns Hopkins Bloomberg School of Public Health Department of International Health, have been looking into the challenges of controlling and eventually eliminating malaria in a multi-country context in southern Africa. We are sharing abstracts from her pioneering work. The first seen below provides an overview of the three components of the study.

Incidence 2012Despite recent reductions in malaria morbidity and mortality due to the scale up of malaria interventions, malaria remains a public health problem in sub-Saharan Africa, especially among children under five years of age, pregnant women and people living with HIV/AIDS. A recent resurgence in malaria, in areas where malaria control was previously successful, has brought to the forefront the importance of research to understand the epidemiology of malaria and the effectiveness of malaria control efforts in resurgent settings. Using cross-sectional surveys, routine data from health-facility based surveillance and freely available remotely sensed environmental data, this research examined the distribution of malaria and the impact of vector control in Mutasa, a rural district in Zimbabwe characterized by resurgent malaria.

Firstly, individual- and household level factors independently associated with individual malaria risk were identified using multilevel logistic regression models based on data from cross-sectional surveys conducted between October 2012 and September 2014. Secondly, geostatistical methods and remotely sensed environmental data were used to model the spatial and seasonal distribution of household malaria risk; then develop seasonal malaria risk maps with corresponding maps of the prediction uncertainty. Lastly, an evaluation of the effect of introducing an organophosphate for indoor residual spraying was conducted using routine health facility data covering 24 months before and 6 months after the campaign.

The results of multilevel model suggested that malaria risk was significantly higher among individuals who were younger than 25 years, did not sleep under a bed net, and lived close to the Zimbabwe-Mozambique border. The spatial risk maps depicted relatively increased risk of finding a positive household in low-lying areas along the Mozambique border during the rainy season. Lastly, the introduction of organophosphates to this pyretheroid resistant area resulted in a significant reduction in malaria incidence following spraying. These findings elucidate the heterogeneous distribution of malaria, identify risk factors driving malaria transmission and assess the quantitative impact of switching insecticide classes on health outcomes. Collectively, the findings provide evidence to guide country-specific decision making for regaining malaria control and underscore the need for strong between-country initiatives to curb malaria in Mutasa District and elsewhere.