Intestinal parasitic infections in a population of BaAka Pygmies inhabiting the Congo Basin in the Central African Republic.

INTRODUCTION: Pygmy tribes inhabit tropical environment of Central Africa. After expulsion from their original habitat by the Bantu people, they settled in a local forest ecosystem where they live with very low sanitary standards. Their actual morbidity remains unknown. OBJECTIVE: The aim of the study was to analyze the prevalence of intestinal parasitic infections in BaAka Pygmies inhabiting the Congo Basin in the Central African Republic. MATERIAL AND METHODS: The study was conducted in 2015, and involved a group of 950 Pygmies living inthe Sangha-Mbaere and Lobaye prefectures. Single stool samples were collected from study participants, fixed in 10% formalin, transported from Africa to Europe, and analyzed by light microscopy using 5 different diagnostic methods (direct smear, decantation with distilled water, Fülleborne's flotation, Kato-Miura thick smear, DiaSyS/PARASYS system sedimentation) at the Military Institute of Medicine in Warsaw, Poland. RESULTS: Microscopic examination revealed infections with 14 different species of intestinal nematodes, cestodes, trematodes and protozoa. According to the study findings, 90.5% of BaAka Pygmies were found to be infected with intestinal parasites, and 70.8% had mixed infections. Most of the pathogenic intestinal parasites were nematodes (85.0%), with Asrcaris lumbricoides (29.8%), hookworm (29.4%) and Trichuris trichiura (10.7%) being predominant. CONCLUSIONS: Poor sanitation, limited the high prevalence of intestinal parasitic infections in the community of Pygmies. The negative test results may prove the effectiveness of periodic deworming campaigns chich, implemented by non-governmental organizations, are voluntary with respect to the informed consent principle.

Evidence for the Adaptive Learning Function of Work and Work-Themed Play among Aka Forager and Ngandu Farmer Children from the Congo Basin.

Work-themed play may allow children to learn complex skills, and ethno-typical and gender-typical behaviors. Thus, play may have made important contributions to the evolution of childhood through the development of embodied capital. Using data from Aka foragers and Ngandu farmer children from the Central African Republic, we ask whether children perform ethno- and gender-typical play and work activities, and whether play prepares children for complex work. Focal follows of 50 Aka and 48 Ngandu children were conducted with the aim of recording children's participation in 12 categories of work and work-themed play. Using these data, we test a set of hypotheses regarding how age, gender, ethnicity, and task complexity influence children's activities. As hypothesized, we find performance of work-themed play is negatively correlated with age. Contrary to our hypothesis, children do not play more than they work at complex tasks, but they work more than they play at simple ones. Gender and ethnicity are associated with play and work at culturally salient activities, despite availability of other-gender and other-ethnicity social partners. Our findings show that ethnic and gender biases are apparent in the play and work behavior of Aka and Ngandu children. Moreover, our results show that play helps both forager and farmer children learn complex skills, consistent with play having an adaptive learning function.

Molecular characterisation of measles virus strains among refugees from Central African Republic in Cameroon in 2014.

Measles is a highly infectious human viral disease caused by measles virus (MeV). An estimated 114 900 measles deaths occurred worldwide in 2014. There are currently eight clades (A-H) comprised 24 MeV genotypes. We sought to characterise MeVs among Central African Republic (CAR) refugees during the 2014 measles epidemic in Cameroon. Samples were collected from children <15 years with suspected measles infections in two refugee camps in the east region of Cameroon. Viral RNA was extracted directly from urine samples. RNA detection of MeV RNA was performed with real-time reverse transcription polymerase chain reaction (PCR) to amplify a 634 bp nucleotide fragment of the N gene. The sequence of the PCR product was obtained to determine the genotype. MeV RNA was detected in 25 out of 30 samples from suspected cases, and among the 25 positive samples, MeV sequences were obtained from 20. The MeV strains characterised were all genotype B3. The MeV strains from genotype B3 found in this outbreak were more similar to those circulating in Northern Cameroon in 2010-2011 than to MeV strains circulating in the CAR in 2011. Surveillance system should be improved to focus on refugees for early detection of and response to outbreaks.

DHEAS patterning across childhood in three sub-Saharan populations: Associations with age, sex, ethnicity, and cortisol.

OBJECTIVES: Hormones have many roles in human ontogeny, including the timing of life history 'switch points' across development. Limited hormonal data exist from non-Western children, leaving a significant gap in our understanding of the diversity of life history patterning. This cross-sectional study examines dehydroepiandrosterone sulfate (DHEAS) production in relation to age, sex, ethnicity, and cortisol concentrations, as well as average age of adrenarche, among Aka and Ngandu children of the Central African Republic and Sidama children of Ethiopia. METHODS: Hair was collected from 480 children (160 per population) aged 3-18 years old. These samples were analyzed for DHEAS and cortisol concentrations using ELISAs. A generalized additive model was used to examine DHEAS patterning in relation to age, sex, cortisol, and ethnicity. The derivative of DHEAS as a function of age was used to identify average age of adrenarche in each population. RESULTS: DHEAS patterning in these three populations is distinct from Euro-American patterns of production. In all three groups, the population-level age at adrenarche onset occurs slightly later than Euro-American averages, with both Central African populations experiencing a later onset than the Ethiopian population. CONCLUSIONS: DHEAS patterns and age at adrenarche vary across cultures, perhaps indicating adaptive life history responses in diverse eco-cultural environments. Delayed involution of the fetal zone and DHEAS patterning may offer both cognitive protection and immune defense in high-risk, nutritionally-poor environments. Additional research in the majority world is essential to improving our understanding of the diversity of hormonal development and timing of 'switch points' in life history trajectories.

Autonomy, Equality, and Teaching among Aka Foragers and Ngandu Farmers of the Congo Basin.

The significance of teaching to the evolution of human culture is under debate. We contribute to the discussion by using a quantitative, cross-cultural comparative approach to investigate the role of teaching in the lives of children in two small-scale societies: Aka foragers and Ngandu farmers of the Central African Republic. Focal follows with behavior coding were used to record social learning experiences of children aged 4 to 16 during daily life. "Teaching" was coded based on a functional definition from evolutionary biology. Frequencies, contexts, and subtypes of teaching as well as the identity of teachers were analyzed. Teaching was rare compared to observational learning, although both forms of social learning were negatively correlated with age. Children received teaching from a variety of individuals, and they also engaged in teaching. Several teaching types were observed, including instruction, negative feedback, and commands. Statistical differences in the distribution of teaching types and the identity of teachers corresponded with contrasting forager vs. farmer foundational cultural schema. For example, Aka children received less instruction, which empirically limits autonomous learning, and were as likely to receive instruction and negative feedback from other children as they were from adults. Commands, however, exhibited a different pattern suggesting a more complex role for this teaching type. Although consistent with claims that teaching is relatively rare in small-scale societies, this evidence supports the conclusion that teaching is a universal, early emerging cognitive ability in humans. However, culture (e.g., values for autonomy and egalitarianism) structures the nature of teaching.

Children's Play and Culture Learning in an Egalitarian Foraging Society.

Few systematic studies of play in foragers exist despite their significance for understanding the breadth of contexts for human development and the ontogeny of cultural learning. Forager societies lack complex social hierarchies, avenues for prestige or wealth accumulation, and formal educational institutions, and thereby represent a contrast to the contexts of most play research. Analysis of systematic observations of children's play among Aka forest foragers (n = 50, ages 4-16, M = 9.5) and Ngandu subsistence farmers (n = 48, ages 4-16, M = 9.1) collected in 2010 illustrates that while play and work trade off during development in both groups, and consistent patterns in sex-role development are evident, Aka children engage in significantly less rough-and-tumble play and competitive games than children among their socially stratified farming neighbors.

A Biocultural Investigation of Gender Differences in Tobacco Use in an Egalitarian Hunter-Gatherer Population.

In the developing world, the dramatic male bias in tobacco use is usually ascribed to pronounced gender disparities in social, political, or economic power. This bias might also reflect under-reporting by woman and/or over-reporting by men. To test the role of gender inequality on gender differences in tobacco use we investigated tobacco use among the Aka, a Congo Basin foraging population noted for its exceptionally high degree of gender equality. We also tested a sexual selection hypothesis-that Aka men's tobacco use is related to risk taking. Tobacco use, income, tobacco purchases, tobacco sharing, reasons for using tobacco, risk taking, and other variables were measured using structured surveys and peer reports. Tobacco use was verified by testing for salivary cotinine, a nicotine metabolite. Contrary to expectations, we found a very large male bias in tobacco use. Low levels of use among females appeared to be explained by aversions to tobacco, concerns over its negative effects on fetal health, and a desire to attract husbands, who prefer nonsmoking wives. High male use appeared to be related to a desire to enhance hunting abilities and attract and/or retain wives, who prefer husbands that smoke. We conclude that low levels of smoking by Aka women are better explained by the hypothesis that women evolved to avoid plant toxins to protect their fetuses and nursing infants. High male use might be better explained by sexual selection. We also highlight the important role that recreational drugs appear to play in hunter-gatherer sharing relationships.

Incertitude, Hepatitis B, and Infant Vaccination in West and Central Africa.

This comparative study explores incertitude about hepatitis B (HBV) and its implications for childhood vaccination in Bangui, Central African Republic, and the Cascades region, Burkina Faso. Anthropological approaches to vaccination, which counter stereotypes of "ignorant" publics needing education to accept vaccination, excavate alternative ways of knowing about illness and vaccination. We build on these approaches, evaluating different kinds of incertitude (ambiguity, uncertainty, ignorance) about infancy, HBV, health protection, and vaccination. Using interviews and participant observation, we find that Bangui and Cascades publics framed their incertitude differently through stories of infancy, illness, and protection. We locate different forms of incertitude within their historical contexts to illuminate why vaccination practices differ in the Cascades region and Bangui. A more nuanced approach to incomplete knowledge, situated in political, economic, and social histories of the state and vaccination, can contribute to more appropriate global health strategies to improve HBV prevention.

Factors associated with dementia among elderly people living in two cities in Central Africa: the EDAC multicenter study.

Risk factors for dementia in American and European countries have been well investigated. However, little research has been carried out in sub-Saharan Africa, where life events as well as environmental, socio-economic, and modifiable risk factors (i.e., cardiovascular risk factors) may differ. Two cross-sectional surveys were conducted in representative samples of the older general population living in Bangui (Central African Republic) and Brazzaville (Congo). Dementia was defined according to the DSM-IV criteria. Multivariate regression analyses were performed in order to identify independent factors associated with dementia. Among the 977 elderly Africans included in this analysis, 75 (7.6%) were diagnosed as having dementia. Increasing age, female gender, hypertension, a body mass index <18.5 kg/m2, depressive symptoms, and the lack of a primary education were significantly associated with dementia. Among life events, the death of one parent during childhood and recently having moved house were also associated with dementia. Beyond the usual risk factors for dementia, this study highlights the role of stressful events in low-income countries. Factors associated with dementia in African countries seem different from established factors in high-income countries and require further investigation.

Multiple caregivers' touch interactions with young children among the Bofi foragers in Central Africa.

The current study examined the use of three types of touch (caregiving, active social-affectionate, and passive social-affectionate) by caregivers with young children among the Bofi foragers, a seminomadic group of hunter-gatherers in Central Africa. With the purpose of providing a more holistic view of touch interactions in early childhood, compared to extant Western mother-centric views, this study documents stylistic touch patterns used by multiple caregivers (mother, father, adult relatives, and juvenile relatives) with Bofi forager children. Thirty-five Bofi forager children, between 18 and 59 months of age, and their various caregivers were naturalistically observed over 12 daylight hours using a focal child observational technique. Frequencies of each type of touch and the rank order of types of touch that children received were compared between caregivers and examined by child age and gender. Even though nonmaternal caregivers showed high physical involvement with children, mothers exemplified the highest level of involvement. Overall, passive social-affectionate touch was utilized the most by all types of caregivers. Mothers used more caregiving touch, and fathers and adult relatives had similar frequencies of caregiving touch and active social-affectionate touch. In contrast, juvenile relatives showed more active social-affectionate touch with focal children. This study highlights the importance of examining multiple caregivers and physical interactions when studying early childhood experiences. Furthermore, by focusing on multiple caregivers and multiple types of touch, this study provides a more thorough characterization of the touch experiences of young children than previous studies of touch. Finally, the current study exemplifies the value of considering non-Western populations when investigating touch interactions.

Konzo outbreak among refugees from Central African Republic in Eastern region, Cameroon.

Konzo is a spastic paraparesis of sudden onset, linked to the exclusive consumption of insufficiently processed bitter cassava as staple food combined with low protein intake. Around 60,000 refugees from the Central African Republic sought refuge in villages in eastern Cameroon between 2005 and 2007. Médecins Sans Frontières was providing nutritional and medical assistance in the villages affected by displacement. We describe cases of konzo seen at the mobile clinics organized in these villages. Basic information including demographic data, history and clinical presentation was recorded for each konzo patient. All patients were given nutritional supplements, and selected cases were referred for physiotherapy to a rehabilitation center. A total of 469 patients were diagnosed with konzo. The majority (80%) were refugees. Children and women of reproductive age predominated. Most of the patients developed symptoms after 2007 in a seasonal pattern with most of the cases occurring during the dry winter season. Most of the patients complained about walking difficulties and weight loss and had exaggerated lower limb reflexes and muscle wasting on observation. Eastern Cameroon is an area with konzo. More effort needs to be put into preventive and educational measures. In addition, timely balanced food rations have to be provided to refugees.

BetaS-haplotypes in sickle cell anemia patients from Salvador, Bahia, Northeastern Brazil.

BetaS-Globin haplotypes were studied in 80 (160 betaS chromosomes) sickle cell disease patients from Salvador, Brazil, a city with a large population of African origin resulting from the slave trade from Western Africa, mainly from the Bay of Benin. Hematological and hemoglobin analyses were carried out by standard methods. The betaS-haplotypes were determined by PCR and dot-blot techniques. A total of 77 (48.1%) chromosomes were characterized as Central African Republic (CAR) haplotype, 73 (45.6%) as Benin (BEN), 1 (0.63%) as Senegal (SEN), and 9 (5.63%) as atypical (Atp). Genotype was CAR/CAR in 17 (21.3%) patients, BEN/BEN in 17 (21.3%), CAR/BEN in 37 (46.3%), BEN/SEN in 1 (1.25%), BEN/Atp in 1 (1.25%), CAR/Atp in 6 (7.5%), and Atp/Atp in 1 (1.25%). Hemoglobin concentrations and hematocrit values did not differ among genotype groups but were significantly higher in 25 patients presenting percent fetal hemoglobin (%HbF) > or = 10% (P = 0.002 and 0.003, respectively). The median HbF concentration was 7.54+/-4.342% for the CAR/CAR genotype, 9.88 3.558% for the BEN/BEN genotype, 8.146 4.631% for the CAR/BEN genotype, and 4.180+/-2.250% for the CAR/Atp genotype (P = 0.02), although 1 CAR/CAR individual presented an HbF concentration as high as 15%. In view of the ethnic and geographical origin of this population, we did not expect a Hardy-Weinberg equilibrium for CAR/CAR and BEN/BEN homozygous haplotypes and a high proportion of heterozygous CAR/BEN haplotypes since the State of Bahia historically received more slaves from Western Africa than from Central Africa.

Variation at 10 protein coding loci in the Mbenzele Pygmies from the Central African Republic and a comparison with microsatellite data.

Ten protein coding loci (6-PGD, A1-AT, ACP1, CaII, ESD, GC, GPX1, Hb beta, PGM1, and TF) were analyzed in the Mbenzele Pygmies from the Central African Republic. The frequency data were used to calculate the genetic distances between Mbenzele Pygmies and other African groups. In the principal coordinate plot of FST genetic distances, the Mbenzele cluster together with other Pygmies of the western cluster, the Biaka from C.A.R., Gielli from Cameroon, and Babinga from Congo. By contrast, they are considerably distanced from other Pygmy groups of the eastern cluster (Twa from Rwanda, Mbuti from Zaire). Genetic distances obtained using protein loci were compared with those based on microsatellite loci. The two distance matrices are insignificantly correlated (r = 0.268; one tail probability = 0.332), and the main difference is in the higher genetic affinity between the Mbenzele and Biaka Pygmies observed at the protein level. Although reasons underlying the discrepancy between inter-populational variation at protein and DNA loci are not established with certainty, the comparison suggests that the genetic distance between the Mbenzele and Biaka Pygmies at microsatellite loci could have been shaped by genetic drift.

Molecular characteristics of pediatric patients with sickle cell anemia and stroke.

Cerebrovascular accidents (CVA) are serious complications of sickle cell anemia (SS) in children. Factors that predispose children to this complication are not well established. In an effort to elucidate the risk factors associated with CVA in SS, we have determined the alpha-globin genotype and the beta(S) haplotype of children with this complication. Among 700 children with SS followed at Children's Hospital of Michigan, 41 (6%) are on chronic transfusions because of stroke due to cerebral infarction. The mean age of patients with CVA at the time of stroke was 5.6 +/- 3.2 years (mean +/- SD). The male/female ratio was 2/3. Only 8 of 41 patients (19.5%) had one alpha-gene deletion, compared to the reported prevalence of 30% in African-Americans. None of the patients had two alpha-gene deletions, and two (5%) had five alpha-genes. These findings are different than those in our adult patients with SS, where the prevalence of -alpha/-alpha and alphaalphaalpha/alphaalpha is 4% and <2%, respectively. Ten different beta(S)-haplotypes were detected in the patients studied. The majority of the patients (31%) were doubly heterozygous for the Ben/CAR haplotypes followed by Ben/Ben, Ben/Sen, and CAR/CAR haplotypes, respectively. The prevalence of these haplotypes, with the exception of the CAR/CAR haplotype, was higher in females than males. All the patients with CAR/CAR haplotype were males, had four alpha-genes, and ranked third in prevalence. Three patients were heterozygous for the Cameron haplotype. The Cameron and atypical haplotypes were more prevalent than reported in patients with SS at large. The data suggest that CVA in children seems to occur more frequently in females and in patients with certain beta(S) haplotype. alpha-Gene deletion seems to offer a protective effect against this complication. Neonates with four or more alpha-genes whose beta(S) haplotype is Ben/CAR, atypical, or CAR/CAR seem to be at a higher risk for CAV than other patients. A prospective study on a larger group of patients with or without CVA may clarify this issue.

HLA class II polymorphism in Aka Pygmies and Bantu Congolese and a reassessment of HLA-DRB1 African diversity.

HLA-DRB1, -DQB1 and -DPB1 polymorphisms were investigated in two African populations, the Basse Lobaye Aka Pygmies of the Central African Republic, and a Bantu-speaking group from the Democratic Republic of Congo Kinshasa. Allelic and haplotypic frequency distributions reveal marked differences between the two populations in spite of their geographical proximity: the Aka exhibit high frequencies for several alleles, especially at the DPB1 locus (0.695 for DPB1*0402), probably due to rapid genetic drift, while the Bantu distributions are more even. Genetic distances computed from DRB1 allelic frequencies among 21 populations from North and sub-Saharan Africa were applied to a multidimensional scaling analysis. African populations genetic structure is significantly shaped by linguistic differentiation, as confirmed by an analysis of molecular variance. However, selective neutrality tests indicate that many African populations exhibit an excess of heterozygotes for DRB1, which is likely to explain the genetic similarity observed between some North African and Bantu populations. Overall, this study shows that natural selection must be taken into account when interpreting the patterns of HLA diversity, but that this effect is probably minor in relation to the stochastic events of human population differentiations.

[Free dissociated and precipitated p24 antigenemia of HIV-1 in subjects of the black race]. / Antigénémie p24 du VIH de type 1, libre, dissociée et précipitée, chez les individus de race noire.

P24/HIV-1 antigen in the sera from 41 HIV-1-infected Black individuals, living in the Central African Republic (n = 17) and in France (n = 24), and in 21 HIV-1-infected Caucasians patients, matched on the stages of the disease, has been detected and quantified by ELISA, without and with acid pretreatment of the sera by HC1 or by glycine, and after ultracentrifugation of serum. Free p24 antigenemia was detected less frequently in Black patients (9.7%), than in Caucasian controls (33%) (p < 0.05). Decomplexed p24 antigenemia was detected in 34% of patients after dissociation of circulating immune complexes (CIC) by HC1 (p < 0.01) and in 44% of patients after dissociation of CIC by glycine (p < 0.001). However, the mean concentration of decomplexed p24 antigenemia of positive sera was higher after pretreatment by HC1 (88 pg/ml) than by glycine (52 pg/ml), suggesting that a strong acid is more convenient than a weak one to disrupt the CIC in Black individuals. After ultracentrifugation of the serum, the detection of p24 antigen was not significantly increased. Acid dissociation of CIC is a usefull method to increase the sensitivity of detection of circulating p24 antigen in HIV-1-infected Black individuals.

The heterogeneity of the beta s cluster haplotypes in Brazil.

The beta s cluster haplotypes were determined for 74 Brazilian patients with sickle cell anemia from three cities separated by 1,400 to 2,300 km. The cities are representative of the regions which have the largest Black populations of the country. All 138 chromosomes with typical haplotypes had one of the three most common African haplotypes. No example of the Asian or of the Cameroon haplotypes was found. The Bantu haplotype predominates in all three regions (54.8 to 73.1%), followed by the Benin haplotype (25.4 to 45.2%) and a small number of cases with the Senegal haplotype (0 to 6.9%). The mean prevalence of the Bantu haplotype of 65.9% agrees closely with historical data which indicate that 70% of the African slaves brought to Brazil originated from regions of Bantu populations.

Beta S-gene-cluster haplotypes in sickle cell anemia: clinical implications.

Restriction endonuclease analysis was used to detect alpha-gene deletions and to determine the haplotypes in the DNA of the beta S-gene-cluster [Benin, Central African Republic (CAR), and Senegal] in 221 patients with sickle cell anemia (SS). The clinical expression of SS was modified by the beta S-gene-cluster polymorphisms and the alpha-gene status (alpha-thalassemia-2). The overall risk of soft tissue organ failure caused by the obliterative sickle vasculopathy (including stroke, renal failure, chronic lung disease with cor pulmonale, leg ulcers, and young adult death) was increased threefold in those with a CAR haplotype and was decreased in those with a Senegalese chromosome (p = 0.003). In the presence of a Senegalese haplotype, the patient's health is better, and with the CAR haplotype it is always worse. With the Benin, it is intermediate. Acute recurrent clinical events including hospitalized sickle cell crisis, bone infarction, and infection are decreased in frequency in those with a Senegalese haplotype. The risk of most acute events including acute chest syndrome is equivalent in those with Benin or CAR haplotypes. In the United States, alpha-thalassemia-2 is co-inherited randomly among the beta S-gene-cluster haplotypes. Acute events occurring during childhood are minimally effected by this co-inheritance. The risk of soft tissue organ failure is decreased. After the age of 20 years, painful episodes of the lumbar dorsal area are increased in patients who had alpha-thalassemia-2 in association with degenerative bone disease.(ABSTRACT TRUNCATED AT 250 WORDS)