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In this study, we analyze clustering of infant deaths within families living in a rural part of western Burkina Faso. The study included 9,220 infants, born between 1993 and 2009 in Nouna Health and Demographic Surveillance System (HDSS). A clustering of infant deaths in families was explored by calculating observed versus expected number of infant deaths within families for a given family size. In addition, risk ratios were calculated for infant death depending on the vital status of the previous sibling. We observed 470 infant deaths, yielding an overall infant mortality risk of 51/1,000 births. Clustering of infant deaths within families was observed (P = 0.004). In smaller families, the mortality of firstborns was higher than for the following siblings. The infant mortality risk was higher when the preceding sibling died in infancy (P = 0.03). The study supports the hypothesis of infant death clustering existing within rural families in West Africa. Further studies are needed to shed more light on these findings with the goal to develop effective interventions directed toward the families who already lost a child.

Ramadan exposure in utero can be regarded as a natural experiment with which to study how nutritional conditions in utero influence susceptibility to disease later in life. We analyzed data from rural Burkina Faso on 41,025 children born between 1993 and 2012, of whom 25,093 were born to Muslim mothers. Ramadan exposure was assigned on the basis of overlap between Ramadan dates and gestation, creating 7 exclusive categories. We used proportional hazards regression with difference-in-differences analysis to estimate the association between Ramadan exposure at different gestational ages and mortality among children under 5 years of age. Under-5 mortality was 32 deaths per 1,000 child-years. Under-5 mortality among Muslims was 15% higher than that among non-Muslims (P < 0.001). In the difference-in-differences analysis, the occurrence of Ramadan during conception or the first or second trimester was associated with higher under-5 mortality rates among Muslims only. The mortality rates of children born to Muslim mothers were 33%, 29%, and 22% higher when Ramadan occurred during conception, the first trimester, and the second trimester, respectively, compared with children of non-Muslim mothers born at the same time (P = 0.01, P < 0.001, and P = 0.007). Having a Muslim mother was not associated with mortality when the child was not exposed to Ramadan, born during Ramadan, or exposed during the third trimester. Observance of Ramadan during early pregnancy can have detrimental consequences for the future health of the unborn child.

Malaria blood-stage vaccines are in an early phase of clinical development with MSP1 being a major antigen candidate. There are limited data on the protective efficacy of antibodies against subunits of MSP1 in the malaria endemic areas of sub-Saharan Africa. This prospective cohort study was nested into a large insecticide-treated mosquito net (ITN) trial during which neonates were individually randomised to ITN protection from birth vs. protection from month six onwards in rural Burkina Faso. A sub sample of 120 children from three villages was followed for 10 months with six measurements of MSP1(42) antibodies (ELISA based on recombinant 42kDa fragment) and daily assessment of malaria episodes. Time to the next malaria episode was determined in relation to MSP1(42) antibody titres. MSP1(42) antibody titres were dependent on age, season, ITN-group, number of previous malaria episodes and parasitaemia. There were no significant differences in time until the next malaria episode in children with low compared to children with high MSP1(42) antibody titres at any point in time (101 vs. 97 days in May, p=0.6; 58 vs. 84 days in September, p=0.3; 144 vs. 161 days in March, p=0.5). The findings of this study support the short-lived nature of the humoral immune response in infants of malaria endemic areas. The study provides no evidence for antibodies against a subunit of MSP1 being protective against new malaria episodes in infants.

We examined the distribution of hematological parameters in 186 adults (89 female, 97 male) living in Nouna, Burkina Faso. Median (5 th - 95 th percentile) hemoglobin concentration was 12.6 (10.3-15.3) g/dl, which was lower than reported from other populations in Africa. Iron deficiency may be the most important reason for this observation.

We assessed changes in the effect size of risk factors for infant mortality comparing a birth cohort from 2005 to 2010 with a birth cohort from 1993 to 1999 in the Nouna Health and Demographic Surveillance System (HDSS) in Burkina Faso. Single- and three-level Cox proportional hazards regression models were used for analysis. Independent variables among others included year of birth, ethnicity, religion, age of the mother, birth order, death of the mother, being a twin, and distance to the closest health facility. We observed an infant mortality rate of about 51/1,000 person-years. The strongest risk factors were death of the mother and being a twin, which were also the strongest risk factors from the previous analysis period. Compared with the period 1993-1999, the effect of most risk factors decreased, notably ethnicity, religious affiliation, distance to the closest health facility, birth order, and season of birth. The strongest reduction in mortality occurred in the groups with the previously highest infant mortality rates in 1993-1999.

To assess the birth of twins in rural Burkina Faso with respect to prevalence, mortality, and provision of obstetric care.A descriptive demographic analysis of population-based and health service data was performed with multivariate modeling by Poisson regression. Health service data were derived from a document review in health facilities in the Nouna District for the years 1994-2001. The district hospital provides obstetric care for the entire district with its 252,000 population (1998). Population-based data (deliveries, live births, deaths) were derived from the demographic surveillance system in the surveillance area within the Nouna District, Burkina Faso (population under surveillance: 30,988 in 1998). All births in the period from January 1, 1993 to December 31, 1998 (9457 recorded deliveries with 9,610 live births) were included and followed up until April 30, 2002. The main outcome measures were the prevalence of twin delivery as well as age- and sex-specific mortality risks.Mortality of twins is high, with one out of three dying before reaching the age of five years--2.5 times the mortality risk of singletons. Among twins, mortality is particularly high in the neonatal period (RR 5.16; CI: 3.6-7.5) and in twins born to mothers above the age of 35 (RR 5.12; CI: 3.5-7.6). The overall population-based prevalence of twin delivery is 1.6% (CI: 1.4-1.9) versus a hospital-based prevalence of 2.8% (CI: 2.2-3.1). Despite this moderate trend towards hospital-based obstetric care, most twins (90.5%) are still delivered outside a hospital setting.The high neonatal mortality in twins points to the need for special care in pregnancy, child birth, and postpartum. Maternity services fail to adequately cover the vast majority of multiple pregnancies and deliveries.

A seroprevalence study was carried out of six different human pathogenic viruses, namely human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), human T-cell leukemia virus (HTLV), human herpesvirus type 8 (HHV-8), and dengue virus among pregnant women and blood donors from rural (Nouna) and urban (Ouagadougou) Burkina Faso, West Africa. A total of 683 samples from blood donors (n = 191) and pregnant women (n = 492) were collected from both sites and screened for the different virus infection markers resulting in the following prevalence values for Nouna or Ouagadougou, respectively: HIV 3.6/4.6, anti-HBV core (anti-HBc) 69.6/76.4, HBV surface antigen (HBsAg)14.3/17.3, HCV 2.2/1.5, HTLV 1.4/0.5, HHV-8 11.5/13.5, dengue virus 26.3/36.5. Individuals aged > or =25 years were more likely to be infected with HIV than those below 24 years (P < 0.05). Infection with HIV increased the likelihood of co-infection with other viruses, such as HHV-8, HBV and HTLV. Co-infection studies involving five viruses (HBV-HBsAg, HHV-8, HIV, HCV, and HTLV) showed that 4.8% (33/683) of the studied population were dually infected, with HBsAg+ HHV-8 (13/33), HBsAg+HIV (8/33) and HIV+HHV-8 (8/33) being the most common co-infections. Of the population studied 0.6% (4/683) was triply infected, the most common infection being with HBV+HIV+HHV-8 (3/4). There was no difference in the prevalence of HIV, anti-HBc, HBsAg, HCV, HTLV, and HHV-8 either among blood donors or pregnant women in urban or rural setting, while dengue virus prevalence was relatively lower in rural (26.3%) than in urban (36.5%) Burkina Faso.

Mortality in developing countries has multiple causes. Some of these causes are linked to climatic conditions that differ over the year. Data on season-specific mortality are sparse.We analysed longitudinal data from a population of approximately 35,000 individuals in Burkina Faso. During the observation period 1993-2001, a total number of 4,098 deaths were recorded. The effect of season on mortality was investigated separately by age group as (i) date of death and (ii) date of birth. For (i), age-specific death rates by month of death were calculated. The relative effect of each month was assessed using the floating relative risk method and modelled continuously. For (ii), age-specific death rates by month of birth were calculated and the mean date of birth among deaths and survivors was compared.Overall mortality was found to be consistently higher during the dry season (November to May). The pattern was seen in all age groups except in infants where a peak was seen around the end of the rainy season. In infants we found a strong association between high mortality and being born during the time period September to February. No effect was seen for the other age groups.The observed excess mortality in young children at or around the end of the rainy season can be explained by the effects of infectious diseases and, in particular, malaria during this time period. In contrast, the excess mortality seen in older children and adults during the early dry season remains largely unexplained although specific infectious diseases such as meningitis and pneumonia are possible main causes. The association between high infant mortality and being born at around the end of the rainy season is probably explained by most of the malaria deaths in areas of high transmission intensity occurring in the second half of infancy.

Based on a demographic surveillance population from 39 villages in rural Burkina Faso, we describe mortality patterns in adults (15‐59 years) and older people (� 60 years), and discuss seasonal trends in mortality. During the study period 1993‐1998, 589 deaths in adults and 593 deaths in older people were recorded from an average adult and older people population of 13 550. The crude all-cause mortality rate per 1000 for adults was 7.3 (95 per cent confidence interval (CI) 6.7‐7.8) and for older people 55.8 (95 per cent CI 51.3‐60.3). The probability of dying before age 60 after reaching age 15 was 34 per cent for males and 32 per cent for females. Malaria and diarrhoea, recorded through verbal autopsy, accounted for 21 per cent of total deaths in adults and 22 per cent in older people. A seasonal trend in mortality for older people with a peak in February was identified. The study shows that malaria is an important cause of death in adulthood.

Objectives Weight at birth is usually considered as an indicator of the health status of a given society. As a result this study was designed to investigate the association between birth weight and maternal factors such as gestational weight gain, pre—pregnancy BMI and socio—economic status in Northern Ghana. Methods The study was a facility-based cross-sectional survey conducted in two districts in the Northern region of Ghana. These districts were purposively sampled to represent a mix of urban, peri—urban and rural population. The current study included 419 mother-infant pairs who delivered at term (37–42 weeks). Mother’s height, pre-pregnancy weight and weight changes were generated from the antenatal records. Questionnaires were administered to establish socio-economic and demographic information of respondents. Maternal factors associated with birth weight were examined using multiple and univariate regressions. Results The mothers were generally well nourished before conception (Underweight 3.82%, Normal 57.76%, Overweight 25.06% and Obesity 13.37%) but approximately half of them could not gain adequate weight according to Institute of Medicine recommendations (Low weight gain 49.64%, Adequate weight gain 42.96% and Excessive weight gain 7.40%). Infants whose mothers had excess weight gain were 431g (95% CI 18–444) heavier compared to those whose mothers gained normal weight, while those whose mothers gained less were 479g (95% CI -682– (-276) lighter. Infants of mothers who were overweight and obese before conception were 246g (95% CI 87–405) and 595g (95% CI 375–815) respectively heavier than those of normal mothers, whereas those whose mothers were underweight were 305g (95% CI -565 –(-44) lighter. The mean birth weight observed was 2.98 ± 0.68 kg. Conclusion Our findings show that pre-pregnancy body mass index and weight gain during pregnancy influence birth weight. Therefore, emphasis should be placed on counseling and assisting pregnant women to stay within the recommended weight gain ranges.

The Nouna demographic surveillance system database was analysed for the period 1993-98. Basic demographic parameters, age-specific and age-standardized mortality rates were calculated and a seasonal variation in mortality was analysed. Poisson regression was used to model the calculated mortality rates and to investigate the seasonal mortality pattern. Both the population distribution by age and the mortality rates reflect a typical pattern of population structures and total mortality in rural Africa as a whole: high childhood mortality and a young population (about 60% are up to age 25; about 10% above age 64). We identified a significant seasonal pattern with highest mortality rates in February. Demographic surveillance systems in Africa provide a viable method for the collection of reliable data on vital events in rural Africa and should therefore be established and supported.

Large scale dietary assessment instruments are usually based on the food frequency technique and have therefore to be tailored to the involved populations with respect to mode of application and inquired food items. In multicenter studies with different populations, the direct comparability of dietary data is therefore a challenge because each local dietary assessment tool might have its specific measurement error. Thus, for risk analysis the direct use of dietary measurements across centers requires a common reference. For example, in the European prospective cohort study EPIC (European Prospective Investigation into Cancer and Nutrition) a 24-hour recall was chosen to serve as such a reference instrument which was based on a highly standardized computer-assisted interview (EPIC-SOFT). The 24-hour recall was applied to a representative subset of EPIC participants in all centers. The theoretical framework of combining multicenter dietary information was previously published in several papers and is called linear regression calibration. It is based on a linear regression of the food frequency questionnaire to the reference. The regression coefficients describe the absolute and proportional scaling bias of the questionnaire with the 24-hour recall taken as reference. This article describes the statistical basis of the calibration approach and presents first empirical results of its application to fruit, cereals and meat consumption in EPIC Germany represented by the two EPIC centers, Heidelberg and Potsdam. It was found that fruit could be measured well by the questionnaire in both centers (λcirc; = 0.98 (males) and λcirc; = 0.95 (females) in Heidelberg, and λcirc; = 0.86 (males) and λcirc; = 0.7 (females) in Potsdam), cereals less (λcirc; = 0.53 (males) and λcirc; = 0.4 (females) in Heidelberg, and λcirc; = 0.53 (males) and λcirc; = 0.44 (females) in Potsdam), and that the assessment of meat (λcirc; = 0.72 (males) and λcirc; = 0.65 (females) in Heidelberg, and λcirc; = 0.49 (males) and λcirc; = 0.42 (females) in Potsdam) has a center-specific bias. The application of the calibration approach to the questionnaire data will change the ranking of the two centers following the data of the reference instrument, and not well-measured food items will exhibit considerably less variation compared to the original data. We conclude that calibration is a necessary step in multicenter studies. However, this exercise shows that the current statistical framework is not yet sufficiently developed for a broad application.

Background This study aimed to investigate the relationship between household wealth and under-5 year mortality in rural and semi-urban Burkina Faso. Methods The study included 15 543 children born between 2005 and 2010 in the Nouna Health and Demographic Surveillance System. Information on household wealth was collected in 2009. Two separate wealth indicators were calculated by principal components analysis for the rural and the semi-urban households, which were then divided into quintiles accordingly. Multivariable Cox proportional hazards regression was used to study the effect of the respective wealth measure on under-5 mortality. Results We observed 1201 childhood deaths, corresponding to 5-year survival probability of 93.6% and 88% in the semi-urban and rural area, respectively. In the semi-urban area, household wealth was significantly related to under-5 mortality after adjustment for confounding. There was a similar but non-significant effect of household wealth on infant mortality, too. There was no effect of household wealth on under-5 mortality in rural children. Conclusions Results from this study indicate that the more privileged children from the semi-urban area with access to piped water and electricity have an advantage in under-5 survival, while under-5 mortality in the rural area is rather homogeneous and still relatively high

Reference ranges for peripheral blood lymphocyte subsets were generated for 186 healthy adults in Burkina Faso using single-platform flow cytometry. CD4 + T-cell counts ranged from 631 to 1,696 cells μl −1 ; they were lower in males ( n = 97) than in females ( n = 89), whereas natural killer cell counts were higher.

Plasmodium sporozoite motility is essential for establishing malaria infections. It depends on initial adhesion to a substrate as well as the continuous turnover of discrete adhesion sites. Adhesion and motility are mediated by a dynamic actin cytoskeleton and surface proteins. The mode of adhesion formation and the integration of adhesion forces into fast and continuous forward locomotion remain largely unknown. Here, we use optical tweezers to directly trap individual parasites and probe adhesion formation. We find that sporozoites lacking the surface proteins TRAP and S6 display distinct defects in initial adhesion; trap(-) sporozoites adhere preferentially with their front end, while s6(-) sporozoites show no such preference. The cohesive strength of the initial adhesion site is differently affected by actin filament depolymerization at distinct adhesion sites along the parasite for trap(-) and s6(-) sporozoites. These spatial differences between TRAP and S6 in their functional interaction with actin filaments show that these proteins have nonredundant roles during adhesion and motility. We suggest that complex protein–protein interactions and signaling events govern the regulation of parasite gliding at different sites along the parasite. Investigating how these events are coordinated will be essential for our understanding of sporozoite gliding motility, which is crucial for malaria infection. Laser tweezers will be a valuable part of the toolset.

To evaluate seasonal patterns of cardiovascular death in adults, which are possibly influenced by hot and dry climate, in a rural setting of Burkina Faso.Cause of death was ascertained by verbal autopsy. Age-specific death rates (cardiovascular death and all-cause) by month of death were calculated. Seasonal trends and temperature effects were modelled with Poisson regression.In 11,174 adults (40+), 1238 deaths were recorded for the period 1999-2003. All-cause mortality in adults (40-64 years) and the elderly (65+ years) was 1269 per 100,000 (95% CI 1156-1382) and 7074 (95% CI 6569-7579), respectively. Cardiovascular death was the fourth most frequent cause of death in adults (40+), with a mortality of 109.9 (95% CI 76.6-143.1) for ages 40-64 and 544.9 (95% CI 404.6-685.1) for ages 65+. For all-causes, the mortality was highest in March and for cardiovascular death highest in April, the hot dry season (March-May). Mean monthly temperature was significantly related to mortality in old ages.Cardiovascular mortality varies by season, with higher mortality rates in the hot dry season. The pattern seems to be consistent with other studies suggesting association between hot weather and cardiovascular disease. A 'heat-wave' effect appears to be observable also in areas with hot average temperatures.

Summary Objective To evaluate seasonal patterns of cardiovascular death in adults, which are possibly influenced by hot and dry climate, in a rural setting of Burkina Faso. Methods Cause of death was ascertained by verbal autopsy. Age-specific death rates (cardiovascular death and all-cause) by month of death were calculated. Seasonal trends and temperature effects were modelled with Poisson regression. Results In 11 174 adults (40+), 1238 deaths were recorded for the period 1999–2003. All-cause mortality in adults (40–64 years) and the elderly (65+ years) was 1269 per 100 000 (95% CI 1156–1382) and 7074 (95% CI 6569–7579), respectively. Cardiovascular death was the fourth most frequent cause of death in adults (40+), with a mortality of 109.9 (95% CI 76.6–143.1) for ages 40–64 and 544.9 (95% CI 404.6–685.1) for ages 65+. For all-causes, the mortality was highest in March and for cardiovascular death highest in April, the hot dry season (March–May). Mean monthly temperature was significantly related to mortality in old ages. Conclusions Cardiovascular mortality varies by season, with higher mortality rates in the hot dry season. The pattern seems to be consistent with other studies suggesting association between hot weather and cardiovascular disease. A ‘heat-wave’ effect appears to be observable also in areas with hot average temperatures. Variations saisonnieres de la mortalite par maladie cardiovasculaire chez les adultes au Burkina-Faso, Afrique de l’Ouest Objectif: Evaluer les tendances saisonnieres de la mortalite cardiovasculaire chez les adultes, peut-etre influencees par un climat chaud et sec, dans un milieu rural du Burkina-Faso. Methodes: La cause du deces a ete verifiee par autopsie verbale. Les taux de mortalite specifique a l’âge (deces d’origine cardiovasculaire et de toutes causes) ont ete calcules. Les tendances saisonnieres et les effets de la temperature ont ete modelises avec une regression de Poisson. Resultats: 1238 deces chez 11.174 adultes (> 40 ans) ont ete enregistres pour la periode entre 1999 a 2003. La mortalite de toutes causes chez les adultes (40-64 ans) et les personnes âgees (> 65 ans) etait de 1269 pour 100.000 (IC95%: 1156-1382) et de 7074 (IC95%: 6569-7579), respectivement. Les deces d’origine cardiovasculaire etaient la quatrieme plus frequente cause de deces chez les adultes (> 40 ans), avec une mortalite de 109,9 (IC95%: 76,6 - 143,1) pour le groupe d’âge 40-64 et 544,9 (IC95%: 404,6 - 685,1) pour le groupe d’âge >65 ans. Pour toutes les causes, la mortaliteetait plus elevee en mars et plus elevee pour les deces d’origine cardiovasculaire en avril, la saison seche et chaude (mars-mai). La temperature moyenne mensuelle etait significativement associee a la mortalite chez les plus âges. Conclusions: La mortalite d’origine cardiovasculaire varie selon la saison, avec des taux de mortalite plus eleves durant la saison seche et chaude. La tendance semble coherente avec celle d’autres etudes suggerant une association entre le climat chaud et les maladies cardiovasculaires. Un effet de “vague de chaleur” apparait aussi observable dans les zones avec des temperatures moyennes chaudes. Patrones estacionales de mortalidad por enfermedades cardiovasculares en adultos en Burkina Faso, Africa Occidental. Objetivo: Evaluar los patrones estacionales de muertes por enfermedad cardiovascular en adultos, lo cual podria estar influenciado por el clima seco y caliente, en un emplazamiento rural Burkina Faso. Metodos: Las causas de muerte se determinaron mediante autopsia verbal. Se calcularon las tasas de muerte especificas por edad (muerte cardiovascular y cualquier causa) y por mes. Las tendencias estacionales y los efectos de la temperatura fueron modelados en una regresion de Poisson. Resultados: Se reportaron 1238 muertes entre 11,174 adultos (40+) para el periodo entre 1999 a 2003. La mortalidad por cualquier causa en adultos (40-64 anos) y personas mayores (65+ anos) fue de 1269 por 100,000 (95% IC 1156-1382) y 7074 (95% IC 6569-7579), respectivamente. La muerte por enfermedad cardiovascular era la cuarta causa de muerte mas frecuente en adultos (40+), con una mortalidad de 109.9 (95% IC 76.6-143.1) para edades entre 40-64 y 544.9 (95% IC 404.6-685.1) para mayores de 65. La mortalidad por cualquier causa era mayor en Marzo, y la muerte por problemas cardiovasculares era mayor en Abril, durante el periodo seco y caliente (Marzo-Mayo.) La temperatura media mensual estaba significativamente relacionada con la mortalidad en edades avanzadas. Conclusiones: La mortalidad por problemas cardiovasculares varia segun la estacion, con una mayor tasa de mortalidad en la estacion seca y calida. El patron parece ser consistente con el reportado en otros estudios, sugiriendo una asociacion entre el clima caliente y la enfermedad cardiovascular. Parece observarse un efecto de “ola de calor”, tambien en areas en las que hay un promedio de altas temperaturas.

Background We describe a step-wedge cluster-randomised community-based trial which has been conducted since 2003 to accompany the implementation of a community health insurance (CHI) scheme in West Africa. The trial aims at overcoming the paucity of evidence-based information on the impact of CHI. Impact is defined in terms of changes in health service utilisation and household protection against the cost of illness. Our exclusive focus on the description and discussion of the methods is justified by the fact that the study relies on a methodology previously applied in the field of disease control, but never in the field of health financing. Methods First, we clarify how clusters were defined both in respect of statistical considerations and of local geographical and socio-cultural concerns. Second, we illustrate how households within clusters were sampled. Third, we expound the data collection process and the survey instruments. Finally, we outline the statistical tools to be applied to estimate the impact of CHI. Conclusion We discuss all design choices both in relation to methodological considerations and to specific ethical and organisational concerns faced in the field. On the basis of the appraisal of our experience, we postulate that conducting relatively sophisticated trials (such as our step-wedge cluster-randomised community-based trial) aimed at generating sound public health evidence, is both feasible and valuable also in low income settings. Our work shows that if accurately designed in conjunction with local health authorities, such trials have the potential to generate sound scientific evidence and do not hinder, but at times even facilitate, the implementation of complex health interventions such as CHI.

Information on cause-specific mortality is sparse in sub-Saharan Africa. We present seasonal patterns of malaria and all-cause mortality from a longitudinal study with 60,000 individuals in rural northwestern Burkina Faso. The study is based on a demographic surveillance system and covers the period 1999-2003. Overall, 3,492 deaths were observed. Cause of death was ascertained by verbal autopsy. Age-specific death rates by cause and month of death were calculated. Seasonal and temporal trends were modeled with parametric Poisson regression. Infant and children less than 5 years of age mortality was 60.6 (95% CI, 56.2-65.3) and 31.9 (95% CI, 30.4-33.5) per 1,000 for all causes and 23.4 (95% CI, 20.7-26.4) and 13.3 (95% CI, 12.3-14.3) for malaria, respectively. Mortality was significantly higher in the rainy season. It is well described parametrically with a sinusoidal function. In adults, the highest all-cause mortality rates were observed in the dry season. Here, HIV/AIDS has become a leading cause of mortality.

In the context of a larger clinical study in Nouna, Burkina Faso, we evaluated a simplified dual-platform (DP) flow cytometric (FCM) method that allows the determination of major lymphocyte subsets in a single test tube. We compared the phenotyping of lymphocytes with DP FCM and simultaneous measurements with standard single-platform (SP) FCM for samples from 177 individuals. Analysis of the comparative measurements revealed that DP FCM systematically underestimates the proportion of NK cells, overestimates the percentage of CD3 + CD8 + lymphocytes, and yields proportions of B cells and CD4 + T cells comparable with the results from SP FCM. Bland-Altman analysis showed a low bias between both methods and an acceptable precision for percent values of CD4 + T cells (bias ± precision, −1% ± 6%) and CD8 + T cells (−3% ± 6%). The absolute cell numbers of all lymphocyte subpopulations, however, were systematically biased towards lower values being obtained by DP FCM. Reference values for the distribution of T-cell maturation phenotypes in 177 healthy adults were calculated using DP FCM. The mean ± standard deviation (SD) CD4 + -to-CD8 + T-cell ratio was 1.61 ± 0.61, the mean percentage ± SD of CD4 + T cells was 42% ± 7%, and that of CD8 + T cells 29% ± 7%. Among CD4 + lymphocytes, 28% ± 7% were classified as central memory (CD45RA low CCR7 + ), 22% ± 10% as naïve (CD45RA high CCR7 + ), 45% ± 12% as effector memory (CD45RA low CCR7 − ); and 5% ± 3% as terminally differentiated effector memory expressing CD45RA (CD45RA high CCR7 − ). Among CD8 bright lymphocytes, 3% ± 2% had a central memory phenotype, 27% ± 13% were naïve, 37% ± 13% had an effector memory phenotype, and 34% ± 12% were terminally differentiated effector memory cells expressing CD45RA.

Background Reliable mortality data are a prerequisite for planning health interventions, yet such data are often not available in developing countries, particularly in sub-Saharan Africa (SSA). Demographic surveillance systems (DSS) implementing the verbal autopsy (VA) method are the only possibility to observe cause-specific mortality of a population on a longitudinal basis in many countries. Methods This paper reports all-cause and cause-specific mortality rates in children under the age of five years from 1999 until 2003 in a malaria holoendemic area of north-western Burkina Faso. The DSS of the Nouna Health Research Centre, in which VA data were analysed, covers a rural population of about 30,000 (41 villages) and an urban population of about 25,000 (Nouna town). Results A total of 1,544 deaths were analysed, 87 (6%), 225 (14%), 317 (21%) and 915 (59%) of which occurred in the periods < 1 month, 1–5 months, 6–11 months and 1–4 years respectively. All cause mortality rates of children under five years were higher in the rural than the urban area (34 vs 24 per 1,000 person-years) and in the rainy than the dry season (35 vs 29 per 1,000 person-years). Malaria was the most frequent diagnosis (42%) with peak mortality rates in infants aged 6–11 months. Conclusion Malaria is the most important cause of death in this remote area of SSA, even considering the low specificity of malaria diagnosis in young children. Strengthening the existing malaria control tools is of prime importance to reduce the high childhood mortality in the endemic areas of SSA.

OBJECTIVE: The aim of the study was to quantify the effect of risk factors for childhood mortality in a typical rural setting in sub-Saharan Africa. METHODS: We performed a survival analysis of births within a population under demographic surveillance from 1992 to 1999 based on data from a demographic surveillance system in 39 villages around Nouna, western Burkina Faso, with a total population of about 30000. All children born alive in the period 1 January 1993 to 31 December 1999 in the study area (n = 10 122) followed-up until 31 December 1999 were included. All-cause childhood mortality was used as outcome variable. FINDINGS: Within the observation time, 1340 deaths were recorded. In a Cox regression model a simultaneous estimation of hazard rate ratios showed death of the mother and being a twin as the strongest risk factors for mortality. For both, the risk was most pronounced in infancy. Further factors associated with mortality include age of the mother, birth spacing, season of birth, village, ethnic group, and distance to the nearest health centre. Finally, there was an overall decrease in childhood mortality over the years 1993-99. CONCLUSION: The study supports the multi-causation of childhood deaths in rural West Africa during the 1990s and supports the overall trend, as observed in other studies, of decreasing childhood mortality in these populations. The observed correlation between the factors highlights the need for multivariate analysis to disentangle the separate effects. These findings illustrate the need for more comprehensive improvement of prenatal and postnatal care in rural sub-Saharan Africa.