Joseph Keating

Malaria prevention in pregnancy, birthweight, and neonatal mortality: a meta-analysis of 32 national cross-sectional datasets in Africa

BACKGROUND Low birthweight is a significant risk factor for neonatal and infant death. A prominent cause of low birthweight is infection with Plasmodium falciparum during pregnancy. Antimalarial intermittent preventive therapy in pregnancy (IPTp) and insecticide-treated mosquito nets (ITNs) significantly reduce the risk of low birthweight in regions of stable malaria transmission. We aimed to assess the effectiveness of malaria prevention in pregnancy (IPTp or ITNs) at preventing low birthweight and neonatal mortality under routine programme conditions in malaria endemic countries of Africa. METHODS We used a retrospective birth cohort from national cross-sectional datasets in 25 African countries from 2000-10. We used all available datasets from multiple indicator cluster surveys, demographic and health surveys, malaria indicator surveys, and AIDS indicator surveys that were publically available as of 2011. We tried to limit confounding bias through exact matching on potential confounding factors associated with both exposure to malaria prevention (ITNs or IPTp with sulfadoxine-pyrimethamine) in pregnancy and birth outcomes, including local malaria transmission, neonatal tetanus vaccination, maternal age and education, and household wealth. We used a logistic regression model to test for associations between malaria prevention in pregnancy and low birthweight, and a Poisson model for the outcome of neonatal mortality. Both models incorporated the matched strata as a random effect, while accounting for additional potential confounding factors with fixed effect covariates. FINDINGS We analysed 32 national cross-sectional datasets. Exposure of women in their first or second pregnancy to full malaria prevention with IPTp or ITNs was significantly associated with decreased risk of neonatal mortality (protective efficacy [PE] 18%, 95% CI 4-30; incidence rate ratio [IRR] 0·820, 95% CI 0·698-0·962), compared with newborn babies of mothers with no protection, after exact matching and controlling for potential confounding factors. Compared with women with no protection, exposure of pregnant women during their first two pregnancies to full malaria prevention in pregnancy through IPTp or ITNs was significantly associated with reduced odds of low birthweight (PE 21%, 14-27; IRR 0·792, 0·732-0·857), as measured by a combination of weight and birth size perceived by the mother, after exact matching and controlling for potential confounding factors. INTERPRETATION Malaria prevention in pregnancy is associated with substantial reductions in neonatal mortality and low birthweight under routine malaria control programme conditions. Malaria control programmes should strive to achieve full protection in pregnant women by both IPTp and ITNs to maximise their benefits. Despite an attempt to mitigate bias and potential confounding by matching women on factors thought to be associated with access to malaria prevention in pregnancy and birth outcomes, some level of confounding bias possibly remains.

Shifts in malaria vector species composition and transmission dynamics along the Kenyan coast over the past 20 years

BackgroundOver the past 20 years, numerous studies have investigated the ecology and behaviour of malaria vectors and Plasmodium falciparum malaria transmission on the coast of Kenya. Substantial progress has been made to control vector populations and reduce high malaria prevalence and severe disease. The goal of this paper was to examine trends over the past 20 years in Anopheles species composition, density, blood-feeding behaviour, and P. falciparum sporozoite transmission along the coast of Kenya.MethodsUsing data collected from 1990 to 2010, vector density, species composition, blood-feeding patterns, and malaria transmission intensity was examined along the Kenyan coast. Mosquitoes were identified to species, based on morphological characteristics and DNA extracted from Anopheles gambiae for amplification. Using negative binomial generalized estimating equations, mosquito abundance over the period were modelled while adjusting for season. A multiple logistic regression model was used to analyse the sporozoite rates.ResultsResults show that in some areas along the Kenyan coast, Anopheles arabiensis and Anopheles merus have replaced An. gambiae sensu stricto (s.s.) and Anopheles funestus as the major mosquito species. Further, there has been a shift from human to animal feeding for both An. gambiae sensu lato (s.l.) (99% to 16%) and An. funestus (100% to 3%), and P. falciparum sporozoite rates have significantly declined over the last 20 years, with the lowest sporozoite rates being observed in 2007 (0.19%) and 2008 (0.34%). There has been, on average, a significant reduction in the abundance of An. gambiae s.l. over the years (IRR = 0.94, 95% CI 0.90–0.98), with the density standing at low levels of an average 0.006 mosquitoes/house in the year 2010.ConclusionReductions in the densities of the major malaria vectors and a shift from human to animal feeding have contributed to the decreased burden of malaria along the Kenyan coast. Vector species composition remains heterogeneous but in many areas An. arabiensis has replaced An. gambiae as the major malaria vector. This has important implications for malaria epidemiology and control given that this vector predominately rests and feeds on humans outdoors. Strategies for vector control need to continue focusing on tools for protecting residents inside houses but additionally employ outdoor control tools because these are essential for further reducing the levels of malaria transmission.

Rolling out insecticide treated nets in Eritrea: examining the determinants of possession and use in malarious zones during the rainy season.

Objective  This paper describes determinants of insecticide treated net (ITN) ownership and use in malarious areas of Eritrea. With ITN distribution and re‐treatment now free for all living in these areas, we examine barriers (other than cost) to access and use of ITNs. We explore the differences between use of an ITN as a proportion of all households in the survey (the roll back malaria indicator), and use of an ITN as a proportion of those households who already own an ITN.

Assessing effects of a media campaign on HIV/AIDS awareness and prevention in Nigeria: results from the VISION Project

BackgroundIn response to the growing HIV epidemic in Nigeria, the U.S. Agency for International Development (USAID) initiated the VISION Project, which aimed to increase use of family planning, child survival, and HIV/AIDS services. The VISION Project used a mass-media campaign that focused on reproductive health and HIV/AIDS prevention. This paper assesses to what extent program exposure translates into increased awareness and prevention of HIV/AIDS.MethodsThis analysis is based on data from the 2002 and 2004 Nigeria (Bauchi, Enugu, and Oyo) Family Planning and Reproductive Health Surveys, which were conducted among adults living in the VISION Project areas. To correct for endogeneity, two-stage logistic regression is used to investigate the effect of program exposure on 1) discussion of HIV/AIDS with a partner, 2) awareness that consistent condom use reduces HIV risk, and 3) condom use at last intercourse.ResultsExposure to the VISION mass media campaign was high: 59%, 47%, and 24% were exposed to at least 1 VISION radio, printed advertisement, or TV program about reproductive health, respectively. The differences in outcome variables between 2002 baseline data and the 2004 follow-up data were small. However, those with high program exposure were almost one and a half (Odds Ratio [O.R.] = 1.47, 95% Confidence Interval [C.I.] 1.01–2.16) times more likely than those with no exposure to have discussed HIV/AIDS with a partner. Those with high program exposure were over twice (O.R. = 2.20, C.I. 1.49–3.25) as likely as those with low exposure to know that condom use can reduce risk of HIV infection. Program exposure had no effect on condom use at last sex.ConclusionThe VISION Project reached a large portion of the population and exposure to mass media programs about reproductive health and HIV prevention topics can help increase HIV/AIDS awareness. Programs that target rural populations, females, and unmarried individuals, and disseminate information on where to obtain condoms, are needed to reduce barriers to condom use. Improvements in HIV/AIDS prevention behaviour are likely to require that these programmatic efforts be continued, scaled up, done in conjunction with other interventions, and targeted towards individuals with specific socio-demographic characteristics.

Strategic roles for behaviour change communication in a changing malaria landscape

Strong evidence suggests that quality strategic behaviour change communication (BCC) can improve malaria prevention and treatment behaviours. As progress is made towards malaria elimination, BCC becomes an even more important tool. BCC can be used 1) to reach populations who remain at risk as transmission dynamics change (e.g. mobile populations), 2) to facilitate identification of people with asymptomatic infections and their compliance with treatment, 3) to inform communities of the optimal timing of malaria control interventions, and 4) to explain changing diagnostic concerns (e.g. increasing false negatives as parasite density and multiplicity of infections fall) and treatment guidelines. The purpose of this commentary is to highlight the benefits and value for money that BCC brings to all aspects of malaria control, and to discuss areas of operations research needed as transmission dynamics change.

Informed Consent in International Research: The Rationale for Different Approaches

In developed countries, informed consent is based on the autonomy of the individual, a written description of the studies proposed, and previous experience of the participant with Western medicine. Consent is documented by the signature of the participant and supervised by institutional review boards (IRBs), which have conflicts of interest because they are also responsible for limiting institutional liability. In developing countries, the initial decision-making for informed consent is typically vested in the community rather than the individual, and illiteracy is common-limiting the value of written documents and signatures. The challenges in developing countries are exacerbated by the fact that persons at greatest risk of disease are often illiterate, have limited experience with Western medicine, and have limited understanding of the scientific rationale for the studies proposed. Given these differences, it is unrealistic to expect that consent strategies used in developed countries would be effective in such diverse settings.

Linking field-based ecological data with remotely sensed data using a geographic information system in two malaria endemic urban areas of Kenya

BackgroundRemote sensing technology provides detailed spectral and thermal images of the earths surface from which surrogate ecological indicators of complex processes can be measured.MethodsRemote sensing data were overlaid onto georeferenced entomological and human ecological data randomly sampled during April and May 2001 in the cities of Kisumu (population ≈ 320,000) and Malindi (population ≈ 81,000), Kenya. Grid cells of 270 meters × 270 meters were used to generate spatial sampling units for each city for the collection of entomological and human ecological field-based data. Multispectral Thermal Imager (MTI) satellite data in the visible spectrum at five meter resolution were acquired for Kisumu and Malindi during February and March 2001, respectively. The MTI data were fit and aggregated to the 270 meter × 270 meter grid cells used in field-based sampling using a geographic information system. The normalized difference vegetation index (NDVI) was calculated and scaled from MTI data for selected grid cells. Regression analysis was used to assess associations between NDVI values and entomological and human ecological variables at the grid cell level.ResultsMultivariate linear regression showed that as household density increased, mean grid cell NDVI decreased (global F-test = 9.81, df 3,72, P-value = <0.01; adjusted R2 = 0.26). Given household density, the number of potential anopheline larval habitats per grid cell also increased with increasing values of mean grid cell NDVI (global F-test = 14.29, df 3,36, P-value = <0.01; adjusted R2 = 0.51).ConclusionsNDVI values obtained from MTI data were successfully overlaid onto georeferenced entomological and human ecological data spatially sampled at a scale of 270 meters × 270 meters. Results demonstrate that NDVI at such a scale was sufficient to describe variations in entomological and human ecological parameters across both cities.

Prevalence of Plasmodium falciparum Infection in Rainy Season, Artibonite Valley, Haiti, 2006

We conducted a population-based survey to estimate the prevalence of Plasmodium falciparum infection among persons older than 1 month in the Artibonite Valley of Haiti during the high malaria transmission season in 2006. Results from PCR for 714 persons showed a prevalence of 3.1% for P. falciparum infection.

Travel history and malaria infection risk in a low-transmission setting in Ethiopia: a case control study

BackgroundMalaria remains the leading communicable disease in Ethiopia, with around one million clinical cases of malaria reported annually. The country currently has plans for elimination for specific geographic areas of the country. Human movement may lead to the maintenance of reservoirs of infection, complicating attempts to eliminate malaria.MethodsAn unmatched case–control study was conducted with 560 adult patients at a Health Centre in central Ethiopia. Patients who received a malaria test were interviewed regarding their recent travel histories. Bivariate and multivariate analyses were conducted to determine if reported travel outside of the home village within the last month was related to malaria infection status.ResultsAfter adjusting for several known confounding factors, travel away from the home village in the last 30 days was a statistically significant risk factor for infection with Plasmodium falciparum (AOR 1.76; p=0.03) but not for infection with Plasmodium vivax (AOR 1.17; p=0.62). Male sex was strongly associated with any malaria infection (AOR 2.00; p=0.001).ConclusionsGiven the importance of identifying reservoir infections, consideration of human movement patterns should factor into decisions regarding elimination and disease prevention, especially when targeted areas are limited to regions within a country.

Chloroquine-Resistant Haplotype Plasmodium falciparum Parasites, Haiti

Chloroquine resistance is now present in this country.