The Lancet Infectious Diseases, Early Online Publication, 18 September 2013

Copyright © 2013 Elsevier Ltd All rights reserved.

• COVERAGE OF INTERMITTENT PREVENTIVE TREATMENT AND INSECTICIDE TREATED NETS FOR THE CONTROL OF MALARIA DURING PREGANCY IN SUB-SAHARAN AFRICA: A SYNTHESIS AND META-ANALYSIS OF NATIONAL SURVEY DATA, 2009—11

Dr Anna Maria van Eijk MD a , Jenny Hill MSc a, David A Larsen PhD b, Jayne Webster PhD c, Richard W SteketeeMD d, Thomas P Eisele PhD e, Prof Feiko O ter Kuile MD a

Background

Pregnant women in malaria-endemic countries in sub-Saharan Africa are especially vulnerable to malaria. Recommended prevention strategies include intermittent preventive treatment with two doses of sulfadoxine—pyrimethamine and the use of insecticide-treated nets. However, progress with implementation has been slow and the Roll Back Malaria Partnership target of 80% coverage of both interventions by 2010 has not been met. We aimed to review the coverage of intermittent preventive treatment, insecticide-treated nets, and antenatal care for pregnant women in sub-Saharan Africa and to explore associations between coverage and individual and country-level factors, including the role of funding for malaria prevention.

Methods

We used data from nationally representative household surveys from 2009—11 to estimate coverage of intermittent preventive treatment, use of insecticide-treated nets, and attendance at antenatal clinics by pregnant women in sub-Saharan Africa. Using demographic data for births and published data for malaria exposure, we also estimated the number of malaria-exposed births (livebirths and stillbirths combined) for 2010 by country. We used meta-regression analysis to investigate the factors associated with coverage of intermittent preventive treatment and use of insecticide-treated nets.

Results

Of the 21·4 million estimated malaria-exposed births across 27 countries in 2010, an estimated 4·6 million (21·5%, 95% CI 19·3—23·7) were born to mothers who received intermittent preventive treatment. Insecticide-treated nets were used during pregnancy for 10·5 million of 26·9 million births across 37 countries (38·8%, 34·6—43·0). Antenatal care was attended at least once by 16·3 of 20·8 million women in 2010 (78·3%, 75·2—81·4; n=26 countries) and at least twice by 14·7 of 19·6 million women (75·1%, 72·9—77·3; n=22 countries). For the countries with previous estimates for 2007, coverage of intermittent preventive treatment increased from 13·1% (11·9—14·3) to 21·2% (18·9—23·5; n=14 countries) and use of insecticide-treated nets increased from 17·9% (15·1—20·7) to 41·6% (37·2—46·0; n=24 countries) in 2010. A fall in coverage by more than 10% was seen in two of 24 countries for intermittent preventive treatment and in three of 30 countries for insecticide-treated nets. High disbursement of funds for malaria control and a long time interval since adoption of the relevant policy were associated with the highest coverage of intermittent preventive treatment. High disbursement of funds for malaria control and high total fertility rate were associated with the greatest use of insecticide-treated nets, whereas a high per-head gross domestic product (GDP) was associated with less use of nets than was a lower GDP. Coverage of intermittent preventive treatment showed greater inequity overall than use of insecticide-treated nets, with richer, educated, and urban women more likely to receive preventive treatment than their poorer, uneducated, rural counterparts.

Interpretation

Although coverage of intermittent preventive treatment and use of insecticide-treated nets by pregnant women has increased in most countries, coverage remains far below international targets, despite fairly high rates of attendance at antenatal clinics. The effect of the implementation of WHOs 2012 policy update for intermittent preventive treatment, which aims to simplify the message and align preventive treatment with the focused antenatal care schedule, should be assessed to find out whether it leads to improvements in coverage.

Funding

Bill & Melinda Gates Foundation.

• PROJECTED IMPACTS OF CLIMATE CHANGE ON ENVIRONMENTAL SUITABILITY FOR MALARIA TRANSMISSION IN WEST AFRICA

Environ Health Perspect; DOI:10.1289/ehp.1206174

Teresa K. Yamana and Elfatih A.B. Eltahir

Author Affiliations open

Ralph M. Parsons Laboratory, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA

Abstract below; full text is at http://ehp.niehs.nih.gov/1206174/

Background: Climate change is expected to affect the distribution of environmental suitability for malaria transmission by altering temperature and rainfall patterns; however, the local and global impacts of climate change on malaria transmission are uncertain.

Objective: We assessed the effect of climate change on malaria transmission in West Africa.

Methods: We coupled a detailed mechanistic hydrology and entomology model with climate projections from general circulation models (GCMs) to predict changes in vectorial capacity, an indication of the risk of human malaria infections, resulting from changes in the availability of mosquito breeding sites and temperature-dependent development rates. Because there is strong disagreement in climate predictions from different GCMs, we focused on the GCM projections that produced the best and worst conditions for malaria transmission in each zone of the study area.

Results: Simulation-based estimates suggest that in the desert fringes of the Sahara, vectorial capacity would increase under the worst-case scenario, but not enough to sustain transmission. In the transitional zone of the Sahel, climate change is predicted to decrease vectorial capacity. In the wetter regions to the south, our estimates suggest an increase in vectorial capacity under all scenarios. However, because malaria is already highly endemic among human populations in these regions, we expect that changes in malaria incidence would be small.

Conclusion: Our findings highlight the importance of rainfall in shaping the impact of climate change on malaria transmission in future climates. Even under the GCM predictions most conducive to malaria transmission, we do not expect to see a significant increase in malaria prevalence in this region.

Citation: Yamana TK, Eltahir EA. 2013. Projected impacts of climate change on environmental suitability for malaria transmission in West Africa. Environ Health Perspect 121:1179–1186; http://dx.doi.org/10.1289/ehp.1206174

Address correspondence to T.K. Yamana, 77 Massachusetts Ave., Room 48-216, Cambridge, MA 02139 USA. Telephone: (617) 253-6596. E-mail: tkcy@mit.edu

This work was funded by the U.S. National Science Foundation (grant EAR-0946280).

The authors declare they have no actual or potential competing financial interests.

Received: 23 October 2012
Accepted: 11 July 2013
Advance Publication: 16 September 2013
Final Publication: 1 October 2013