Pregnant women in malaria-endemic countries in sub-Saharan Africa are especially vulnerable to ma... more 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. 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. 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. 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 WHO's 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. Bill & Melinda Gates Foundation.
Malaria is highly heterogeneous in space. Remotely sensed environmental and geographic factors ar... more Malaria is highly heterogeneous in space. Remotely sensed environmental and geographic factors are associated with vector density and vector breeding sites, respectively. The identification of clusters and absences of malaria parasite prevalence can help malaria control programs better target interventions. Both the log--relative risk derived from the kernel intensity function and the spatial scan statistic revealed a striking pattern of malaria parasite prevalence clusters and absences in Gwembe and Sinazongwe districts, Southern Province Zambia. The kernel intensity function more aptly classified households as falling within a cluster or absence. Both environmental and geographic factors are associated with core and periphery malaria absences. Geographic factors but not environmental factors are associated with core and periphery malaria clusters. The presence of vector breeding sites may be an important indicator of a core malaria cluster.
It is well known that malaria clusters in both space and time, suggesting that malaria interventi... more It is well known that malaria clusters in both space and time, suggesting that malaria interventions may be targeted. The question of how to target malaria interventions toward those at highest risk remains unresolved. This manuscripts utilizes the difference in K function to show that how malaria--infected individuals cluster in space varies depending on malaria prevalence and the season. Village malaria prevalence was used as a proxy for the spatial distribution of malaria-infected individuals to determine what factors are the largest influences on the spatial distribution. The enhanced vegetation index and multiple rounds of mass malaria screening and treatment were highly associated with village malaria prevalence, suggesting that vector density and gametocyte circulation are leading contributors to differing spatial distributions. Malaria control programs should continue universal coverage in high prevalence areas, but may target highly clustered infections in low prevalence areas.
In the pursuit of establishing 5 malaria free zones Zambia implemented multiple mass malaria scre... more In the pursuit of establishing 5 malaria free zones Zambia implemented multiple mass malaria screening and treatment interventions in Southern Province. The pilot round of intervention was initiated at the beginning of the wet season in December 2011 and January 2012. A randomized post--only comparison showed no association with the pilot intervention and malaria parasite prevalence in children <5 (AOR = 1.45, 95% CI = 0.80 -1.62). A pre--post comparison in intervention areas only showed no association with the pilot intervention and malaria parasite prevalence in all individuals (AOR = 0.87, 95% CI = 0.56 -1.35). A randomized longitudinal comparison of health facility malaria incidence suggested the pilot intervention was associated with a decrease in malaria incidence (IRR = 0.63, 95% CI = 0.52 -0.76). A single round of mass malaria screening and treatment may not
Background: Insecticide-treated mosquito nets (ITNs) and indoor-residual spraying have been scale... more Background: Insecticide-treated mosquito nets (ITNs) and indoor-residual spraying have been scaled-up across sub-Saharan Africa as part of international efforts to control malaria. These interventions have the potential to significantly impact child survival. The Lives Saved Tool (LiST) was developed to provide national and regional estimates of cause-specific mortality based on the extent of intervention coverage scale-up. We compared the percent reduction in all-cause child mortality estimated by LiST against measured reductions in all-cause child mortality from studies assessing the impact of vector control interventions in Africa. Methods: We performed a literature search for appropriate studies and compared reductions in all-cause child mortality estimated by LiST to 4 studies that estimated changes in all-cause child mortality following the scale-up of vector control interventions. The following key parameters measured by each study were applied to available country projections: baseline all-cause child mortality rate, proportion of mortality due to malaria, and population coverage of vector control interventions at baseline and follow-up years. Results: The percent reduction in all-cause child mortality estimated by the LiST model fell within the confidence intervals around the measured mortality reductions for all 4 studies. Two of the LiST estimates overestimated the mortality reductions by 6.1 and 4.2 percentage points (33% and 35% relative to the measured estimates), while two underestimated the mortality reductions by 4.7 and 6.2 percentage points (22% and 25% relative to the measured estimates).
Background and Methods: Roll Back Malaria set the goal of 100% of households in malaria endemic c... more Background and Methods: Roll Back Malaria set the goal of 100% of households in malaria endemic countries in Africa owning an insecticide-treated mosquito net (ITN) by 2010. Zambia has used mass free distribution campaigns and distribution through antenatal care (ANC) clinics to achieve high coverage.
Background: Funding from external agencies for malaria control in Africa has increased dramatical... more Background: Funding from external agencies for malaria control in Africa has increased dramatically over the past decade resulting in substantial increases in population coverage by effective malaria prevention interventions. This unprecedented effort to scale-up malaria interventions is likely improving child survival and will likely contribute to meeting Millennium Development Goal (MDG) 4 to reduce the < 5 mortality rate by two thirds between 1990 and 2015.
Impact of insecticide-treated bednets (ITNs) on preventing malaria may be minimized if they are n... more Impact of insecticide-treated bednets (ITNs) on preventing malaria may be minimized if they are not used by vulnerable populations. Among ITN-owning households from 15 standardized national surveys from 2003 to 2006, we identify factors associated with ITN use among children younger than 5 years of age and make comparisons of ITN use among children and pregnant women across countries. Within ITN-owning households, many children and pregnant women are still not using them. Between-country analysis with linear regression showed child ITN use increases as intrahousehold access to ITNs increases ( P = 0.020, R 2 = 0.404), after controlling for season and survey year. Results from within-country logistic regression analyses were consistent with between-country analysis showing intra-household access to ITNs is the strongest and most consistent determinant of use among children. The gaps in ITN use and possession will likely persist in the absence of achieving a ratio of no more than two people per ITN.
Pregnant women in malaria-endemic countries in sub-Saharan Africa are especially vulnerable to ma... more 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. 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. 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. 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 WHO&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s 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. Bill &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Melinda Gates Foundation.
Malaria is highly heterogeneous in space. Remotely sensed environmental and geographic factors ar... more Malaria is highly heterogeneous in space. Remotely sensed environmental and geographic factors are associated with vector density and vector breeding sites, respectively. The identification of clusters and absences of malaria parasite prevalence can help malaria control programs better target interventions. Both the log--relative risk derived from the kernel intensity function and the spatial scan statistic revealed a striking pattern of malaria parasite prevalence clusters and absences in Gwembe and Sinazongwe districts, Southern Province Zambia. The kernel intensity function more aptly classified households as falling within a cluster or absence. Both environmental and geographic factors are associated with core and periphery malaria absences. Geographic factors but not environmental factors are associated with core and periphery malaria clusters. The presence of vector breeding sites may be an important indicator of a core malaria cluster.
It is well known that malaria clusters in both space and time, suggesting that malaria interventi... more It is well known that malaria clusters in both space and time, suggesting that malaria interventions may be targeted. The question of how to target malaria interventions toward those at highest risk remains unresolved. This manuscripts utilizes the difference in K function to show that how malaria--infected individuals cluster in space varies depending on malaria prevalence and the season. Village malaria prevalence was used as a proxy for the spatial distribution of malaria-infected individuals to determine what factors are the largest influences on the spatial distribution. The enhanced vegetation index and multiple rounds of mass malaria screening and treatment were highly associated with village malaria prevalence, suggesting that vector density and gametocyte circulation are leading contributors to differing spatial distributions. Malaria control programs should continue universal coverage in high prevalence areas, but may target highly clustered infections in low prevalence areas.
In the pursuit of establishing 5 malaria free zones Zambia implemented multiple mass malaria scre... more In the pursuit of establishing 5 malaria free zones Zambia implemented multiple mass malaria screening and treatment interventions in Southern Province. The pilot round of intervention was initiated at the beginning of the wet season in December 2011 and January 2012. A randomized post--only comparison showed no association with the pilot intervention and malaria parasite prevalence in children <5 (AOR = 1.45, 95% CI = 0.80 -1.62). A pre--post comparison in intervention areas only showed no association with the pilot intervention and malaria parasite prevalence in all individuals (AOR = 0.87, 95% CI = 0.56 -1.35). A randomized longitudinal comparison of health facility malaria incidence suggested the pilot intervention was associated with a decrease in malaria incidence (IRR = 0.63, 95% CI = 0.52 -0.76). A single round of mass malaria screening and treatment may not
Background: Insecticide-treated mosquito nets (ITNs) and indoor-residual spraying have been scale... more Background: Insecticide-treated mosquito nets (ITNs) and indoor-residual spraying have been scaled-up across sub-Saharan Africa as part of international efforts to control malaria. These interventions have the potential to significantly impact child survival. The Lives Saved Tool (LiST) was developed to provide national and regional estimates of cause-specific mortality based on the extent of intervention coverage scale-up. We compared the percent reduction in all-cause child mortality estimated by LiST against measured reductions in all-cause child mortality from studies assessing the impact of vector control interventions in Africa. Methods: We performed a literature search for appropriate studies and compared reductions in all-cause child mortality estimated by LiST to 4 studies that estimated changes in all-cause child mortality following the scale-up of vector control interventions. The following key parameters measured by each study were applied to available country projections: baseline all-cause child mortality rate, proportion of mortality due to malaria, and population coverage of vector control interventions at baseline and follow-up years. Results: The percent reduction in all-cause child mortality estimated by the LiST model fell within the confidence intervals around the measured mortality reductions for all 4 studies. Two of the LiST estimates overestimated the mortality reductions by 6.1 and 4.2 percentage points (33% and 35% relative to the measured estimates), while two underestimated the mortality reductions by 4.7 and 6.2 percentage points (22% and 25% relative to the measured estimates).
Background and Methods: Roll Back Malaria set the goal of 100% of households in malaria endemic c... more Background and Methods: Roll Back Malaria set the goal of 100% of households in malaria endemic countries in Africa owning an insecticide-treated mosquito net (ITN) by 2010. Zambia has used mass free distribution campaigns and distribution through antenatal care (ANC) clinics to achieve high coverage.
Background: Funding from external agencies for malaria control in Africa has increased dramatical... more Background: Funding from external agencies for malaria control in Africa has increased dramatically over the past decade resulting in substantial increases in population coverage by effective malaria prevention interventions. This unprecedented effort to scale-up malaria interventions is likely improving child survival and will likely contribute to meeting Millennium Development Goal (MDG) 4 to reduce the < 5 mortality rate by two thirds between 1990 and 2015.
Impact of insecticide-treated bednets (ITNs) on preventing malaria may be minimized if they are n... more Impact of insecticide-treated bednets (ITNs) on preventing malaria may be minimized if they are not used by vulnerable populations. Among ITN-owning households from 15 standardized national surveys from 2003 to 2006, we identify factors associated with ITN use among children younger than 5 years of age and make comparisons of ITN use among children and pregnant women across countries. Within ITN-owning households, many children and pregnant women are still not using them. Between-country analysis with linear regression showed child ITN use increases as intrahousehold access to ITNs increases ( P = 0.020, R 2 = 0.404), after controlling for season and survey year. Results from within-country logistic regression analyses were consistent with between-country analysis showing intra-household access to ITNs is the strongest and most consistent determinant of use among children. The gaps in ITN use and possession will likely persist in the absence of achieving a ratio of no more than two people per ITN.
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