Rice yellow mottle virus is a suitable amplicon vector for an efficient production of an anti-leishmianiasis vaccine in Nicotiana benthamiana leaves

BACKGROUND

Since the 2000's, plants have been used as bioreactors for the transient production of molecules of interest such as vaccines. To improve protein yield, "amplicon" vectors based on plant viruses are used. These viral constructs, engineered to carry the gene of interest replicate strongly once introduced into the plant cell, allowing significant accumulation of the protein. Here, we evaluated the suitability of the monocot-infecting RNA virus Rice yellow mottle virus (RYMV) as an amplicon vector. The promastigote surface antigen (PSA) of the protozoan Leishmania was considered as a protein of interest due to its vaccine properties against canine leishmaniasis.

RESULTS

Since P1 (ORF1) and CP (ORF3) proteins are not strictly necessary for viral replication, ORF1 was deleted and the PSA gene was substituted to ORF3 in the RYMV-based vector. We evaluated its expression in the best described plant bioreactor system, Nicotiana benthamiana which, unlike rice, allows transient transformation by Agrobacterium. Despite not being its natural host, we demonstrated a low level of RYMV-based vector replication in N. benthamiana leaves. Under optimized ratio, we showed that the P19 silencing suppressor in combination with the missing viral CP ORF significantly enhanced RYMV amplicon replication in N. benthamiana. Under these optimized CP/P19 conditions, we showed that the RYMV amplicon replicated autonomously in the infiltrated N. benthamiana cells, but was unable to move out of the infiltrated zones. Finally, we showed that when the RYMV amplicon was expressed under the optimized conditions we set up, it allowed enhanced PSA protein accumulation in N. benthamiana compared to the PSA coding sequence driven by the 35S promoter without amplicon background.

CONCLUSION

This work demonstrates that a non-dicot-infecting virus can be used as an amplicon vector for the efficient production of proteins of interest such as PSA in N. benthamiana leaves.

In vitro activities and mechanisms of action of anti-cancer molecules from African medicinal plants: a systematic review

Cancer is one of the leading causes of death worldwide. In recent years, African countries have been faced with a rapid increase in morbidity and mortality due to this pathology. Management is often complicated by the high treatment costs, side effects and the increasing occurrence of resistance to treatments. The identification of new active ingredients extracted from endemic medicinal plants is definitively an interesting approach for the implementation of new therapeutic strategies: their extraction is often lower cost; their identification is based on an ethnobotanical history and a tradipratic approach; their use by low-income populations is simpler; this can help in the development of new synthetic molecules that are more active, more effective and with fewer side effects. The objective of this review is to document the molecules derived from African medicinal plants whose in vitro anti-cancer activities and the mechanisms of molecular actions have been identified. From the scientific databases Science Direct, PubMed and Google Scholar, we searched for publications on compounds isolated from African medicinal plants and having activity on cancer cells in culture. The data were analyzed in particular with regard to the cytotoxicity of the compounds and their mode of action. A total of 90 compounds of these African medicinal plants were selected. They come from nine chemical groups: alkaloids, flavonoids, polyphenols, quinones, saponins, steroids, terpenoids, xanthones and organic sulfides. These compounds have been associated with several cellular effects: i) Cytotoxicity, including caspase activation, alteration of mitochondrial membrane potential, and/or induction of reactive oxygen species (ROS); ii) Anti-angiogenesis; iii) Anti-metastatic properties. This review points out that the cited African plants are rich in active ingredients with anticancer properties. It also stresses that screening of these anti-tumor active ingredients should be continued at the continental scale. Altogether, this work provides a rational basis for the selection of phytochemical compounds for use in clinical trials.

Association of HLA-DRB1*11 and HLA-DRB1*12 gene polymorphism with COVID-19 in Burkina Faso

BACKGROUND

The clinical manifestations of coronavirus disease (COVID-19) can vary widely, ranging from asymptomatic to severe, and may be influenced by the host genetic background. The aim of the present study was to determine the frequencies of HLA-DRB1*11 and HLA-DRB1*12 allele polymorphisms and their associations with COVID-19.

METHODS

In this cross-sectional study, 198 subjects were enrolled, including 150 COVID-19 positive cases and 48 subjects who tested negative for COVID-19. Participants were recruited from the emergency, intensive care, and infectious diseases departments of the Bogodogo Centre University Hospital (CHU-B) or the routine laboratory of Centre de Recherche Biomoléculaire Pietro Annigoni (CERBA). Genomic DNA was extracted from nasopharyngeal swabs samples and multiplex PCR-SSP was used to detect the HLA-DRB1*11 and HLA-DRB1*12 alleles. The study was approved by CERS (№ 2021-02-033).

RESULTS

The positive cases were categorized into 38 asymptomatic (CC+), 60 symptomatic (NC+), and 52 severe cases (SC+). Females were more frequent in the overall study population (53.0%, 105/198) as well as in the negative group's CC- (68.75%, 33/48) and SC+ (57.69%, 30/52 negative groups, whereas males were more frequent in the CC+ (63.16%, 24/38) and NC+ (53.33%, 32/60) groups. The highest mean age was observed in the SC + group. A frequency of 19.19% (38/198) and 14.65% (29/198) was found for the HLA-DRB1*11 and HLA-DRB1*12 alleles, respectively. Individuals carrying the HLA-DRB1*11 allele had an approximately sixfold higher risk of asymptomatic SARS-CoV-2 infection (OR = 5.72 [1.683-19.442], p = 0.005) based on the association analysis.

CONCLUSIONS

Altogether, the present study reports high frequency of HLA-DRB1*11 and HLA-DRB1*12 alleles within a population from Ouagadougou, Burkina Faso. The results suggest that individuals carrying the HLA-DRB1*11 allele are more susceptible to COVID-19 infection but may not display symptoms.

Launch of the Laboratory for Major Tropical Epidemics (LAGET) in Chad: Strengthening the capacity for epidemiological surveillance, monitoring and diagnosis of endemic or emerging infectious diseases in Central Africa

In an increasingly interconnected world, with the devastating effects of climate changes and humanitarian crises, pandemics and emerging infectious diseases are more likely to become our daily reality. When it comes to health care, sub-Saharan Africa faces more challenges than most other regions of the world, including lack of funds, precarity and poor infrastructures. Yet, these areas are most often on the front lines of infectious threats.

Seasonal Malaria Chemoprevention Implementation: Effect on Malaria Incidence and Immunity in a Context of Expansion of P. falciparum Resistant Genotypes with Potential Reduction of the Effectiveness in Sub-Saharan Africa

Seasonal Malaria Chemoprevention (SMC), which combines amodiaquine (AQ) with sulfadoxine-pyrimethamine (SP), is an effective and promising strategy, recommended by WHO, for controlling malaria morbidity and mortality in areas of intense seasonal transmission. Despite the effectiveness of this strategy, a number of controversies regarding the impact of the development of malaria-specific immunity and challenges of the strategy in the context of increasing and expanding antimalarial drugs resistance but also the limited coverage of the SMC in children make the relevance of the SMC questionable, especially in view of the financial and logistical investments. Indeed, the number of malaria cases in the target group, children under 5 years old, has increased while the implementation of SMC is been extended in several African countries. This ambivalence of the SMC strategy, the increase in the prevalence of malaria cases suggests the need to evaluate the SMC and understand some of the factors that may hinder the success of this strategy in the implementation areas. The present review discusses the impact of the SMC on malaria morbidity, parasite resistance to antimalarial drugs, molecular and the immunity affecting the incidence of malaria in children. This approach will contribute to improving the malaria control strategy in highly seasonal transmission areas where the SMC is implemented.

Isolation and Identification of Escherichia coli and Klebsiella pneumoniae Strains Resistant to the Oxyimino-Cephalosporins and the Monobactam by Production of GES Type Extended Spectrum Bêta-Lactamase (ESBL) at Saint Camille Hospital Center in Ouagadougou, Burkina Faso

Background

Bacterial resistance to beta lactamins is a real public health problem as it complicates treatment strategies. Several types of beta lactamase confer this resistance. Numerous studies report a high prevalence of ESBL producers among Gram-negative bacilli. The objective of this work was to identify the presence of the resistance gene GES in strains of E. coli and K. pneumoniae in Burkina Faso.

Methods

During this study 39 strains of E. coli and K. pneumoniae resistant to oxyimino-cephalosporin and monobactam were collected in several samples and analyzed to determine the presence of the beta lactamase resistance gene Bla_GES by classic PCR.

Results

In the present study, resistant strains were observed in 21 E. coli and 18 K. pneumoniae. Among producers of ESBL isolates, the presence of the GES gene was detected up to 63% in E. coli and 37% in K pneumoniae.

Conclusion

This study highlighted the presence of the GES gene in strains of E. coli and K. pneumoniae resistant to oxyimino-cephalosporin and monobactam in Burkina Faso. This highlights the presence of new ESBL in Burkina, which is of great interest for the proper care of patients and the control of resistance to antibiotics.

Cervical cancer in the Hauts-Bassins region of Burkina Faso: Results of a screening campaign by visual inspection with acetic acid (VIA screening in Burkina Faso)

This study was conducted to describe the distribution of precancerous and cancerous lesions of the cervix uteri, enumerated during a mass screening in Burkina Faso. We conducted a cross-sectional study involving 577 women aged 18 to 60 years, carried out from November 23 to December 19, 2013, in the city of Bobo-Dioulasso and in the rural commune of Bama. Regarding the screening results, 89 participants (15.4%) were positive for pre-malignant cervical lesions. Chi-square testing and logistic regression analyses were conducted to identify the likelihood of cervical pre-cancer lesion in the women. Participants less than 29 years old were approximately 3 times more likely to have cervical lesions than participants >39 years. Participants who were parous (1-3 deliveries) and multiparous (four or more deliveries) were approximately 4 times more likely to present with cervical lesions than nulliparous women. Access to screening services is low in the Bobo-Dioulasso region. Further research should be conducted to understand the incidence and distribution of cervical precancerous and cancerous lesions in Burkina Faso.

Epidemiological assessment of cassava mosaic disease in Burkina Faso

Surveys were conducted in 2016 and 2017 across the main cassava-growing regions of Burkina Faso to assess the status of cassava mosaic disease (CMD) and to determine the virus strains causing the disease, using field observation and phylogenetic analysis. CMD incidence varied between regions and across years but was lowest in Hauts-Bassins (6.0%, 2016 and 5.4%, 2017) and highest in Centre-Sud (18.5%, 2016) and in Boucle du Mouhoun (51.7%, 2017). The lowest CMD severity was found in Est region (2.0) for both years and the highest in Sud-Ouest region (3.3, 2016) and Centre-Sud region (2.8, 2017). The CMD infection was primarily associated with contaminated cuttings in all regions except in Hauts-Bassins, where whitefly-borne infection was higher than cuttings-borne infection in 2016. PCR screening of 687 samples coupled with sequence analysis revealed the presence of African cassava mosaic-like (ACMV-like) viruses and East African cassava mosaic-like (EACMV-like) viruses as single infections at 79.5% and 1.1%, respectively. Co-infections of ACMV-like and EACMV-like viruses were detected in 19.4% of the tested samples. In addition, 86.7% of the samples positive for EACMV-like virus were found to be positive for East African cassava mosaic Cameroon virus (EACMCMV). Phylogenetic analysis revealed the segregation of cassava mosaic geminiviruses (CMGs) from Burkina Faso into three clades specific to ACMV, African cassava mosaic Burkina Faso virus (ACMBFV), and EACMCMV, confirming the presence of these viruses. The results of this study show that EACMCMV occurrence may be more prevalent in Burkina Faso than previously thought.

Glutathione S-transferase M1 and T1 genes deletion polymorphisms and blood pressure control among treated essential hypertensive patients in Burkina Faso

OBJECTIVE

Glutathione S-transferases have been associated with experimental resistance to some drugs. The present study investigated the factors associated with blood pressure control in patients with essential hypertension, especially the role of GSTT1 and GSTM1 genes polymorphisms. This cross-sectional study in Burkina Faso consisted of 200 patients with essential hypertension and under treatment.

RESULTS

In the present study, 57.5% (115/200) of patients had their hypertension under control. No statistically significant difference was found between controlled and uncontrolled groups for anthropometric and biochemical parameters as well as for GSTT1 or GSTM1 gene polymorphisms (all p > 0.05). Current alcohol consumption (OR = 3.04; CI 1.88-6.13; p < 0.001), Physical inactivity (OR = 3.07; CI 1.71-5.49; p < 0.001), severe hypertension before any treatment (Grade III [OR = 3.79; CI 2.00-7.17; p < 0.001]) and heart damage (OR = 3, 14; CI 1.59-6.02; p < 0.001) were statistically more frequent in uncontrolled essential hypertensive patients than controlled hypertensive patients.

Pharmacokinetic study of two different rifabutin doses co-administered with lopinavir/ritonavir in African HIV and tuberculosis co-infected adult patients

Background

This study aimed to assess the pharmacokinetic profile of 150 mg rifabutin (RBT) taken every other day (every 48 h) versus 300 mg RBT taken every other day (E.O.D), both in combination with lopinavir/ritonavir (LPV/r), in adult patients with human immunodeficiency virus (HIV) and tuberculosis (TB) co-infection.

Methods

This is a two-arm, open-label, pharmacokinetic, randomised study conducted in Burkina Faso between May 2013 and December 2015. Enrolled patients were randomised to receive either 150 mg RBT EOD (arm A, 9 subjects) or 300 mg RBT EOD (arm B, 7 subjects), both associated with LPV/r taken twice daily. RBT plasma concentrations were evaluated after 2 weeks of combined HIV and TB treatment. Samples were collected just before drug ingestion and at 1, 2, 3, 4, 6, 8, and 12 h after drug ingestion to measure plasma drug concentration using an HPLC-MS/MS assay.

Results

The Cmax and AUC_0–12h medians in arm A (Cmax = 296 ng/mL, IQR: 205–45; AUC_0–12h = 2528 ng.h/mL, IQR: 1684–2735) were lower than those in arm B (Cmax = 600 ng/mL, IQR: 403–717; AUC_0–12h = 4042.5 ng.h/mL, IQR: 3469–5761), with a statistically significant difference in AUC_0–12h (p = 0.044) but not in Cmax (p = 0.313). No significant differences were observed in Tmax (3 h versus 4 h). Five patients had a Cmax below the plasma therapeutic limit (< 300 ng/mL) in the 150 mg RBT arm, while the Cmax was above this threshold for all patients in the 300 mg RBT arm. Additionally, at 48 h after drug ingestion, all patients had a mycobacterial minimum inhibitory concentration (MIC) above the limit (> 64 ng/mL) in the 300 mg RBT arm, while 4/9 patients had such values in the 150 mg RBT arm.

Conclusion

This study confirmed that the 150 mg dose of rifabutin ingested EOD in combination with LPV/r is inadequate and could lead to selection of rifamycin-resistant mycobacteria.

Trial registration

PACTR201310000629390, 28th October 2013.

Glutathione S-transferase M1 and T1 genes deletion polymorphisms and risk of developing essential hypertension: a case-control study in Burkina Faso population (West Africa)

BACKGROUND

Glutathione S-transferases play a key role in the detoxification of persistent oxidative stress products which are one of several risks factors that may be associated with many types of disease processes such as cancer, diabetes, and hypertension. In the present study, we characterize the null genotypes of GSTM1 and GSTT1 in order to investigate the association between them and the risk of developing essential hypertension.

METHODS

We conducted a case-control study in Burkina Faso, including 245 subjects with essential hypertension as case and 269 control subjects with normal blood pressure. Presence of the GSTT1 and GSTM1 was determined using conventional multiplex polymerase chain reaction followed by gel electrophoresis analysis. Biochemical parameters were measured using chemistry analyzer CYANExpert 130.

RESULTS

Chi-squared test shows that GSTT1-null (OR = 1.82; p = 0.001) and GSTM1-active/GSTT1-null genotypes (OR = 2.33; p <  0.001) were significantly higher in cases than controls; the differences were not significant for GSTM1-null, GSTM1-null/GSTT1-active and GSTM1-null/GSTT1-null (p > 0.05). Multinomial logistic regression revealed that age ≥ 50 years, central obesity, family history of hypertension, obesity, alcohol intake and GSTT1 deletion were in decreasing order independent risk factors for essential hypertension. Analysis by gender, BMI and alcohol showed that association of GSTT1-null with risk of essential hypertension seems to be significant when BMI < 30 Kg/m², in non-smokers and in alcohol users (all OR ≥ 1.77; p ≤ 0.008). Concerning GSTT1, GSTM1 and cardiovascular risk markers levels in hypertensive group, we found that subjects with GSTT1-null genotype had higher waist circumference and higher HDL cholesterol level than those with GSTT1-active (all p <  0.005), subjects with GSTM1-null genotype had lower triglyceride than those with GSTM1-active (p = 0.02) and subjects with the double deletion GSTM1-null/GSTT1-null had higher body mass index, higher waist circumference and higher HDL cholesterol than those with GSTM1-active/GSTT1-active genotype (all p = 0.01).

CONCLUSION

Our results confirm that GSTT1-null genotype is significantly associated with risk of developing essential hypertension in Burkinabe, especially when BMI < 30 Kg/m², in non-smokers and in alcohol users, and it showed that the double deletion GSTM1-null/GSTT1-null genotypes may influence body lipids repartition.

Positive association between ATP2B1 rs17249754 and essential hypertension: a case-control study in Burkina Faso, West Africa

Background

Genetic and environment play a significant role in the etiology of essential hypertension (EH). Recently STK39 rs3754777, ATP2B1 rs2681472 and rs17249754 have been associated with BP variation and hypertension. In this study we aimed to determine firstly whether index variants were associated with the risk of developing EH in Burkina Faso and secondly to characterize cardiovascular risk markers.

Methods

We conducted a case-control study with 380 participants including 180 case subjects with EH and 200 control subjects with normal BP. We used TaqMan genotyping assays with probes from Applied Biosystems to genotype polymorphisms using the 7500 Real-Time PCR System. Biochemical parameters were measured using chemistry analyzer COBAS C311.

Results

T-test showed that cardiovascular risk markers such as body mass index, waist circumference, blood sugar, total cholesterol and triglycerides were significantly higher in hypertensive compared to normotensive (all p <  0.05). Binary logistic regression analysis revealed in decreasing order that overweight, family history of hypertension, central obesity and alcohol intake increased the risk of developing EH (all OR > 3.8; all p <  0.001).

In genetic level we observed that individuals carrying the AA+AG genotype of ATP2B1 rs17249754 had a low risk of developing EH than those carrying the GG genotype (OR = 0.48 [95% CI: 0.31–0.75] p = 0.001) and the A allele frequency in the cases was significantly lower than that of the controls (OR = 0.56 [95% CI: 0.38–0.82] p = 0.003). We also observed that ATP2B1 rs17249754 was significantly associated with higher SBP and DPB in case and control groups (GG versus AG + AA; p <  0.05), ATP2B1 rs2681472 was significantly associated with higher SBP only in case and control group (AA versus AG + GG; p <  0.05), STK39 rs3754777 was not significantly associated with any of the BP traits (CC versus CT + TT; p > 0.05).

Conclusion

Our results confirmed the significant association of ATP2B1 rs17249754 with the risk of developing EH in Burkinabe and showed an increase of cardiovascular risk markers levels in subjects with EH.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1136-x) contains supplementary material, which is available to authorized users.

Multiparity and Breast Cancer Risk Factor among Women in Burkina Faso

The relative lack of information on breast cancer etiology in Burkina Faso led us to undertake the present work to highlight risk factors. This prospective study was conducted using a questionnaire between January 2015 and February 2016 on women admitted to Yalgado OUEDRAOGO hospital, for consultation or supervision. The characteristics of multiparous breast cancer patients (n = 44) were compared with their non-multiparous counterparts (n = 36). The study found that increased risk of breast cancer among non-multiparous cases was related to body mass index (BMI) (p <0.001), age at menopause (p <0.004) and use of oral contraception (p <0.021) while abortion (p <0.002) was a risk factor among multiparous cases. These results suggest that even if multiparity is associated with a decreased risk in some women, avoidance of abortion during reproductive life should be recommended. The results provide preliminary information, which now need to be supplemented by survey of a larger sample in the national territory.

[Effectiveness of Prevention of Mother to Child Transmission of Human Immunodeficiency Virus by the 2010 protocol of the World Health Organisation at the Medical Center St. Camille of Ouagadougou (Burkina Faso)]

L’épidémie du Virus de l'Immunodéficience Humaine en milieu pédiatrique est surtout le résultat de la transmission mère-enfant. Notre étude a pour objectif de décrire l'efficacité de la prévention de la transmission mère-enfant du Virus de l'Immunodéficience Humaine par le protocole OMS 2010 (Option A et trithérapie) au centre médical saint Camille de Ouagadougou. Nous avons mené une étude d'une cohorte d'enfants suivis dans le cadre de la prévention de la transmission mère-enfant du Virus de l'Immunodéficience Humaine au centre médical saint Camille de Ouagadougou sur une période de 2 ans allant du 1er Janvier 2012 au 31 Décembre 2013. Nous avons obtenu l'accord de 4900 femmes enceintes pour le dépistage de l'infection du Virus de l'Immunodéficience Humaine et 238 gestantes ont été diagnostiquées séropositives soit 4,86% de séroprévalence. Les femmes étaient surtout infectées par le Virus de l'Immunodéficience Humaine avec de type I (95,38%)). La majorité était sous trithérapie (74,3%) et (25,7%) sous prophylaxie (option A). Les nouveau-nés (92,5%) ont reçu un traitement antirétroviral à base de névirapine dans les 72 heures après la naissance. L'allaitement sécurisé a été appliquée dans 78% des cas. Le taux global de transmission mère-enfant du VIH était de 3,6% avec 3% de transmission chez les enfants nés de mères sous trithérapie antirétrovirale et 6,3% dans les cas de prophylaxie antirétrovirale. Le facteur de risque de transmission a été le long délai du début d'administration des antirétroviraux chez le nouveau-né. La mortalité infantile à un an était de 3,5%. Cette étude a révélé l'efficacité de l'Option A et conforté celle de la trithérapie, le passage à l'Option B+ serait donc plus bénéfique.

The Modalities of Nonadherence to Highly Active Antiretroviral Therapy and the Associated Factors Related to Patients' Sociodemographic Characteristics and Their Caregiving Perceptions in Ouagadougou (Burkina Faso)

BACKGROUND

The authors studied the modalities of nonadherence to highly active antiretroviral therapy (HAART) and its sociodemographic associated factors and those in relation to caregiving perception in Ouagadougou.

METHODS

A cross-sectional study was performed from December 2013 to February 2014 in 2 health centers. Adults receiving HAART for at least 3 months were included. Adherence was studied according to the quantitative, qualitative, and global criteria. Factors associated with nonadherence were analyzed with chi-square and Fisher tests. A logistic regression model was applied for multivariate analysis.

RESULTS

The authors studied 152 patients: mean age 40.7 ± 7.8 years and sex ratio 0.34. Frequencies were 7.2% for self-reported quantitative, 20.4% for calculated quantitative, 31.6% for qualitative, and 38.2% for global nonadherence. Married status (P = .02), patient's dissatisfaction regarding clinical monitoring (P = .01), and therapeutic education (P = .03) were associated with nonadherence. In multivariate analysis, married status remains associated (odds ratio = 7.00, 95% confidence interval = 1.89-25.8, P = .0004).

CONCLUSION

Nonadherence to HAART needs to be correctly managed during HIV/AIDS monitoring.

[Sleep disorders, anxiety and depressive symptoms and cardiovascular risk among black African hypertensive: cross-sectional study of 414 hypertensive followed as outpatients at the University Hospital of Ouagadougou (Burkina Faso)]

Introduction

Dans le but de déterminer la fréquence des troubles du sommeil, de l'anxiété et de la dépression, et de rechercher l'existence d'une relation entre ces troubles et le risque cardio-vasculaire global chez les hypertendus noirs africains, nous avons réalisé une étude transversale de mai 2010 à mars 2011 à l'unité de consultation externe du service de cardiologie du CHU-Yalgado Ouédraogo de Ouagadougou qui a inclut 414 hypertendus adultes suivis en ambulatoire. Après un examen clinique à la recherche des facteurs de risque cardio-vasculaire, deux auto-questionnaires ont été administrés.

Méthodes

Le questionnaire de l’«European Sleep Center » pour la recherche des troubles du sommeil et, l’échelle «Hospital Anxiety and Depression Scale » de Zigmond et Snaith pour la recherche de l'anxiété et la dépression. Le diagnostic du syndrome d'apnée du sommeil était clinique et basé sur la présence des 4 symptômes principaux: hypersomnolence diurne, éveils nocturnes fréquents avec nycturie, asthénie matinale avec ou sans céphalées et ronflements importants. Le risque cardio-vasculaire global était calculé grâce à l’équation d'Anderson tirée de l’étude de Framingham. L'analyse des données a été réalisée par le logiciel SPSS version 17. La comparaison des variables a été effectuée grâce au test de Khi 2 pour les variables qualitatives et au test «t» de Student pour les variables quantitatives. Le seuil de signification a été fixé à 5%.

Résultats

L’échantillon était composé de 414 patients dont 248 femmes (59,9%). L’âge moyen était de 54,6 ± 9,3 ans. Les troubles du sommeil étaient retrouvés dans 72,2% des cas. Ils étaient dominés par l'insomnie (49,2%), le syndrome d'apnée du sommeil (33,5%) et le syndrome des jambes sans repos (25,8%). L'anxiété était retrouvée dans 37,1% des cas et la dépression dans 16,6% des cas. Le risque cardio-vasculaire global était faible dans 21,0%, modéré dans 33,6%, élevé dans 24,4% et très élevé dans 21,0% des cas. Le syndrome d'apnée du sommeil (p=0,033), le syndrome des jambes sans repos (p=0,005), l'anxiété (p=0,0021) et la dépression (p=0,0001) étaient significativement associés à un risque cardio-vasculaire élevé à très élevé.

Conclusion

Les troubles du sommeil, l'anxiété et la dépression sont fréquents chez les hypertendus noirs africains. Ils sont liés à un niveau de risque cardio-vasculaire élevé. Leur dépistage devrait être intégré à la prise en charge des hypertendus.

[Neurological complications of infective endocarditis in Burkina Faso. Clinical features, management and evolutionary profile]

INTRODUCTION

Neurological complications are the most frequent extracardiac complications of infective endocarditis (IE). This study aimed to describe the epidemiological, clinical and paraclinical aspects, and outcome of neurological complications of infective endocarditis in three hospitals in the city of Ouagadougou in Burkina Faso.

PATIENTS AND METHOD

From 1 January 2009 to 31 December 2012, we included all patients suffering from IE and selected those in whom a neurological complication was objectified. Neurological involvement was sought on clinical examination but especially CT brain (ischemic infarcts, hemorrhages, aneurysms and abscesses). Blood cultures were systematic. Echocardiography was done for vegetations and characteristics.

RESULTS

Among 63 cases of IE, neurological complications were found in 14 patients (22.2%). The average age of patients with neurological complications was 37.4 ± 5.8 years. The sex ratio was 1.3 for women. Neurological damage consisted of nine cases of stroke (64.3%), three cases of hemorrhagic stroke (21.4%) and two cases of brain abscess (14.3%). Neurological complications had already occurred before hospitalization in 4 cases. Blood cultures were positive in 8 cases. Germs found were predominantly Staphylococcus aureus (5 cases) and Streptococcus a- viridans (2 cases). All cases of S. aureus were complicated by stroke. At echocardiography, vegetation was found in all cases. It was found on the mitral in 7 cases, the aorta in 3 cases, the mitral and aortic in 2 cases and the mitral and tricuspid in 2 cases also. The EI had occurred on a native valve in 11 cases, prosthesis in 4 cases (2 mitral and 2 aortic). The vegetations average diameter was 11.2 ± 2.1 mm (6.4 and 1 7.7 mm). Vegetations were mobile in 12 cases. The treatment consisted of antibiotics adapted to the antibiogram, neurological and cardiovascular monitoring. The evolution was marked by seven deaths (50%), including 5 deaths related to cerebral complication (71.4% of deaths).

CONCLUSION

This study shows that neurological complications during infective endocarditis are frequent, dominated by stroke with a high mortality.

Reference ranges of cholesterol sub-fractions in random healthy adults in Ouagadougou, Burkina Faso

In Burkina Faso, the values that serve as clinical chemistry reference ranges are those provided by European manufacturers' insert sheets based on reference of the Western population. However, studies conducted so far in some African countries reported significant differences in normal laboratory ranges compared with those of the industrialized world. The aim of this study was to determine reference values of cholesterol fractions in apparently normal adults in Burkina Faso that could be used to better assess the risks related to cardiovascular diseases. Study population was 279 healthy subjects aged from 15 to 50 years including 139 men and 140 women recruited at the Regional Center of Blood Transfusion of Ouagadougou, capital city of Burkina Faso (West Africa). Exclusion criteria based on history and clinical examination were used for defining reference individuals. The dual-step precipitation of HDL cholesterol sub-fractions using dextran sulfate was performed according to the procedure described by Hirano. The medians were calculated and reference values were determined at 2.5th and 97.5th percentiles. The median and upper ranges for total cholesterol, LDL cholesterol, total HDL cholesterol and HDL2 cholesterol were observed to be higher in women in comparison to men (p <0.05). These reference ranges were similar to those derived from other African countries but lower than those recorded in France and in USA. This underscores the need for such comprehensible establishment of reference values for limited resources countries. Our study provides the first cholesterol sub-fractions (HDL2 and HDL3) reference ranges for interpretation of laboratory results for cardiovascular risk management in Burkina Faso.

Seroprevalence of latent Toxoplasma gondii infection among HIV-infected pregnant women in Bobo-Dioulasso, Burkina Faso

The deficit of cellular immunity, as found in HIV infected individuals, may lead to the reactivation of latent Toxoplasma gondii cysts, with as consequence, the occurrence of toxoplasmosis and an eventual vertical transmission of the disease during pregnancy. The present study was designed for determining the occurrence of latent Toxoplasma gondii among HIV-infected pregnant women during the first trimester in Bobo-Dioulasso. Thus, 348 pregnant women aged from 17 to 47 years (average age of 6.64 ± 4.75 yaers) were enrolled. The specific anti-Toxoplasma gondii IgG and IgM antibodies were quantified from whole blood specimens using the high-sensitivity direct agglutination and the enzyme linked fluorescent assays, respectively, the IgG avidity test being used for the dating of the primary infection. The results revealed that the seroprevalence of Toxoplasma gondii latent infection was 34.7%. It was significantly higher in HIV-infected women compared with uninfected ones (68,7%; CI 95%: 43,6%-88,9%) versus (33,1%; CI 95%: 28, 2%-38,3%). In addition, all the occurrences of the high IgG avidity were closely linked with the presence of IgM. These results underlined the need for the clinical follow-up of the maternal HIV diseases including the toxoplasmosis during the pregnancy since; the newborns are still exposed to vertical transmission of Toxoplasma infection in endemic areas like Burkina Faso.

[Epidemiological characteristics and clinical features of black African subject's resistant hypertension]

INTRODUCTION

Few studies in sub-Saharan Africa were interested in resistant hypertension. The objectives of this study were to determine the frequency of resistant hypertension in hypertensive black African population, and to describe its clinical and therapeutic features.

PATIENTS AND METHODS

From May 1, 2010 to May 31, 2012, we included consecutively hypertensive followed in two hospitals in the city of Ouagadougou, under antihypertensive treatment at optimum dose and observant. Patients whose blood pressure was uncontrolled despite a triple antihypertensive therapy at the optimal dose including a diuretic associated with dietary measures have received ambulatory blood pressure monitoring. Following this examination, patients whose blood pressure was ≥135/85mmHg during the day and/or ≥120/70mmHg at night were considered resistant hypertension. We investigated the cardiovascular risk factors as well as target organ damages. We combined spironolactone 50mg in treatment when absence of contra-indication appreciated the evolution of blood pressure under this treatment. The measurement of plasma renin activity was not performed. Statistical analysis was performed using SPSS Version 17 for Windows.

RESULTS

We included 692 patients with 14.6% of resistant hypertension. The average age of patients was 54.8±11.1years in the general population, 56.5±11.8years in the subgroup of non-resistant hypertension and 64.2±5.4years in the subgroup of resistant hypertension. The symptoms were represented by headache (11.9%), dizziness (9.9%) and chest pain (8.9%). Modifiable cardiovascular risk factors were dominated by dyslipidemia, diabetes and obesity/overweight. These risk factors were significantly more frequent in the subgroup of resistant hypertension. The global cardiovascular risk was high in 24.9% of cases in the general population, 22.5% in the subgroup of non-resistant hypertension and 38.6% in the subgroup of resistant hypertension. The target organ damages were significantly more frequent in the same subgroup of resistant hypertension. After addition of spironolactone, 21.8% of resistant hypertensive patients were controlled.

CONCLUSION

This study shows that resistant hypertension is common in black Africans. It is mostly subjects of the sixth decade, with limited economic income and living in rural areas. In the absence of contra-indication, spironolactone contributed to decrease the morbidity of this pathology.

Caractérisation de la flore bactérienne des péritonites communautaires opérées au Burkina Faso

Introduction

Méthodes

Résultats

Conclusion

Aspects épidémiologiques, cliniques et étiologiques des douleurs thoraciques en consultation externe de cardiologie à Ouagadougou

Introduction

La douleur thoracique est un motif fréquent de consultation en cardiologie à tous les âges. L'objectif de ce travail était de décrire les aspects épidémiologique, clinique et étiologique des douleurs thoraciques en consultation externe de cardiologie.

Methods

Il s'est agi d'une étude transversale descriptive réalisée dans deux hôpitaux de la ville de Ouagadougou. Nous avons enregistré les patients reçus en consultation externe de cardiologie pour douleur thoracique. Lorsque l'examen clinique et le bilan paraclinique plausible étaient non contributifs, la douleur était déclarée sans étiologie. Les données ont été analysées à l'aide du logiciel SPSS version 17.

Results

Durant la période de l’étude, 25664 consultations ont été réalisées. La douleur thoracique était motif de consultation dans 19,7% des cas. L’âge moyen des patients consultant pour douleur thoracique était de 44,4 ± 16,2 ans (extrêmes de 14 et 78 ans) avec un sex-ratio de 1,08 en faveur des femmes. Le bulletin de consultation en cardiologie avait été rédigé par un médecin dans 29,4% des cas. Les douleurs thoraciques étaient à prédominance retrosternale dans 28,7% des cas, épigastrique dans 23,9% des cas et basithoracique dans 13,8% des cas. L'intensité était jugée faible dans 73,6% des cas. Il s'agissait essentiellement de douleur à type de brûlure dans 40,5% des cas. Les étiologies étaient dominées par les causes cardiaques (37,6%) et digestives (31,9%). Parmi les étiologies cardiaques les valvulopathies rhumatismales (34,4%), le rhumatisme articulaire aigu (24,9%) et l'insuffisance coronarienne (19,5%) étaient les plus fréquentes.

Conclusion

Les douleurs thoraciques sont fréquentes en consultation externe de cardiologie. Les étiologies sont surtout cardiaques et digestives. Les étiologies cardiaques sont dominées par la pathologie rhumatismale. Les étiologies extracardiaques sont nombreuses. Ce constat est probablement lié aux consultations directes des patients et aux orientations faites par le personnel paramédical.

Knowledge, attitudes and practice (KAP) regarding newborn feeding modalities in HIV-infected and HIV-uninfected pregnant women in sub-Saharan Africa: a multicentre study

Exclusive formula feeding, exclusive breastfeeding (EBF) with early weaning or the administration of antiretroviral therapy to lactating mothers and/or to breastfed newborns may lower postnatal HIV transmission. The aim of this study was to assess mothers' knowledge, attitudes and practice (KAP) on lactation in various real-life settings in sub-Saharan Africa. A questionnaire survey investigating KAP with regard to breastfeeding in pregnant women of unknown status (Questionnaire A, 16 items) or HIV-infected women (Questionnaire B, 37 items) was administered. Associations between newborn feeding KAP and demographic, socioeconomic, cultural and obstetric variables were investigated. From January 2007 to January 2008, 2112 pregnant women answered Questionnaire A in Burkina Faso, Cameroon, Chad, Tanzania, Uganda and Zambia. Most women (53.0%) declared EBF as the preferred feeding modality. The practice of strictly defined EBF in previous pregnancies was only 11.4%, which was inversely correlated with education and parity. Questionnaire B was answered by 225 HIV-infected pregnant women in Burkina Faso, Tanzania and Uganda. Knowledge about the lactation-associated risk was associated with previous dead children. Significant variability was observed among collaborating sites. The introduction of fluids other than maternal milk within 6 months of age is common practice in sub-Saharan Africa, requiring intensive health education efforts if strictly defined EBF is to be adopted to decrease HIV postnatal transmission. Significant variation in newborn feeding determinants was observed.

Seroprevalence of toxoplasmosis and rubella in pregnant women attending antenatal private clinic at Ouagadougou, Burkina Faso

OBJECTIVE

To evaluate the prevalence of toxoplasmosis and rubella among pregnant women at Ouagadougou in Burkina Faso.

METHODS

All patient sera were tested for rubella and toxoplasmosis anti-IgG using commercial ELISA kits (Platelia™ Rubella IgG and Platelia™ Toxo IgG). The presence of anti-rubella and anti-toxoplasmosis IgM in serum samples was tested using commercial ELISA kits Platelia Rubella IgM and Platelia Toxo IgM.

RESULTS

Among all the pregnant women tested for toxoplasmosis and rubella, their prevalence were 20.3% and 77.0%, respectively. Pregnant women in the age group of 18-25 years showed the highest frequency of anti-toxoplasmosis (34.5%) and anti-rubella IgG (84.6%). The prevalence of anti-toxoplasma and anti-rubella IgG decreased between 2006 and 2008 from 32.7% to 12.1% and 84.6% to 65.0%, respectively. There was no significant association between age and the mean titer of anti-toxoplasmosis IgG among pregnant women.

CONCLUSIONS

The diagnosis of toxoplasmosis and rubella is necessary in pregnant women in Burkina Faso because of the low immunization coverage rate of rubella and the high level of exposure to these two infections which can be harmful to the newborn if contracted by women before the third trimester of pregnancy.

An engineered Plasmodium falciparum C-terminal 19-kilodalton merozoite surface protein 1 vaccine candidate induces high levels of interferon-gamma production associated with cellular immune responses to specific peptide sequences in Gambian adults naturally exposed to malaria

The 19-kDa C-terminal region of merozoite surface protein 1 (MSP1(19)), a major blood stage malaria vaccine candidate, is the target of cellular and humoral immune responses in humans naturally infected with Plasmodium falciparum. We have previously described engineered variants of this protein, designed to be better vaccine candidates, but the human immune response to these proteins has not been characterized fully. Here we have investigated the antigenicity of one such variant compared to wild-type MSP1(19)-derived protein and peptides. Gambian adults produced both high T helper type 1 (Th1) [interferon (IFN)-γ] and Th0/Th2 [interleukin (IL)-13 and sCD30] responses to the wild-type MSP1(19) and the modified protein as wells as to peptides derived from both forms. Response to the modified MSP1(19) (with three amino acid substitutions: Glu27Tyr, Leu31Arg and Glu43Leu) relative to the wild-type, included higher IFN-γ production. Interestingly, some peptides evoked different patterns of cytokine responses. Modified peptides induced higher IL-13 production than the wild-type, while the conserved peptides P16 and P19 induced the highest IFN-γ and IL-13 and/or sCD30 release, respectively. We identified P16 as the immunodominant peptide that was recognized by cells from 63% of the study population, and not restricted to any particular human leucocyte antigen D-related (HLA-DR) type. These findings provide new and very useful information for future vaccine development and formulation as well as potential Th1/Th2 immunmodulation using either wild-type or modified protein in combination with their peptides.

[Prevalence and risk factors associated with infection by human immunodeficiency virus, hepatitis B virus, syphilis and bacillary pulmonary tuberculosis in prisons in Burkina Faso]

This purpose of this study was to determine prevalences and risk factors associated with infection by human immunodeficiency virus, hepatitis B Virus, syphilis and bacillary pulmonary tuberculosis in prisons in Burkina Faso. From February 20 to March 20, 2009, 300 prisoners over 18 years of age held in Ouagadougou were selected to take part in this descriptive and analytical cross-sectional study. Sociodemographic data, confinement information (number, motive and prison time), medical history, substance addiction (alcohol, tobacco, drug), and the other risk behaviors (sexual relations, type of partners, sharing of toiletries or razor) were compiled for each prisoner. Serological tests were performed to detect anti-HIV antibodies, Hbs antigen, and anti-treponema antibody. In prisoners presenting signs of tuberculosis, BAAR detection was performed by direct examination of sputum. Men represented 95% of the study population. Median age was of 30.1 +/- 8.9 years (range, 18 and 63). The prevalences of HIV infection, Hbs antigen and positive syphilitic serology were 5%, 27.3% and 5.7% respectively. Four prisoners (1.3%) had bacillary pulmonary tuberculosis. Two prisoners reported homosexual intercourse and 44 reported drug abuse. Sharing of toiletries and razor blades was reported by 18.7% and 20% of the prisoners respectively. Immediate measures are needed reduce the spread of these infections in prisons in Africa.

[Molecular diagnosis of acquired human immunodeficiency virus (HIV) in pooled plasma from blood donors at the Regional Blood Transfusion Center in Ouagadougou, Burkina Faso]

STUDY OBJECTIVES

The aim of this pilot study was to investigate the use of viral genome diagnosis of HIV-1 infection in blood donors in the regional blood transfusion center in Ouagadougou, Burkina Faso.

METHODOLOGY

This prospective study was carried out from August to December 2009 at the regional blood transfusion center in Ouagadougou (RBTC-O). Detection of HIV-1 was performed by RT-PCR on pooled plasma and individual samples from blood donors. Samples were selected based on reactivity with fourth generation ELISA.

RESULTS

ELISA assays on 20 plasma pools demonstrated 10 negative samples, 8 positive and 2 undeterminable. All positive and negative ELISA tests were confirmed by RT-PCR. Findings of RT-PCR on individual samples confirmed those obtained on pooled plasma samples. For the two undeterminable pools, RT-PCR identified one as negative and the other as positive. Individual RT-PCR testing of donations contained in positive and negative pooled plasma samples confirmed negative or positive findings.

CONCLUSIONS

Because of the high cost of RT-PCR, we recommend use first on minipools or individual samples from blood donors with questionable HIV-1 status to confirm status quickly and minimize loss of blood bags.

Anthropological features of the CFTR gene: Its variability in an African population

BACKGROUND

The CFTR gene (Cystic Fibrosis conductance Transmembrane Regulator) is the gene responsible for Cystic Fibrosis, the most common severe autosomal recessive disease in Europeans. It has been extensively explored in several European and European-derived populations, but poorly studied in the other major human groups.

AIM

To characterize the variability of the CFTR gene in an African population.

SUBJECTS AND METHODS

Using DGGE, all 27 exons (4443 bp) and 2184 bp of the flanking intronic regions of the CFTR gene were studied in a random sample of 45 Mossì from Burkina Faso (Western sub-Saharan Africa).

RESULTS

Sixteen variable sites were found: 13 SNPs (one in the promoter region, four non-synonymous and five synonymous in the exons and three in the introns) and three intronic STRs. Only the promoter site ( - 94 G/T), slightly polymorphic in the present survey, was not variable in different European populations. Comparison between Western Africans, Eastern Africans, Europeans and Eastern Asians showed that alleles at two intronic STRs (T(n) and (TG)(m) in intron 8), four exonic (M470V, 2694 T/G, 4002 A/G and 4521 G/A) and one intronic (875+40 A/G) SNPs have very different frequencies among at least two major human groups. Moreover, the overall degree of non-synonymous variability in Mossì is much lower than that in Europeans. A possible interpretation of this finding is proposed.

CONCLUSIONS

The CFTR gene has been since long hypothesized to have undergone selection in Europeans. The present study by comparing Africans and Europeans for the overall variability of the gene supports this hypothesis.

Incidence of tuberculosis after HAART initiation in a cohort of HIV-positive patients in Burkina Faso

OBJECTIVE

To determine the incidence rates of tuberculosis (TB) after the initiation of highly active antiretroviral treatment (HAART).

METHODS

We conducted a retrospective cohort study on four human immunodeficiency virus (HIV) treatment centres in Ouagadougou, Burkina Faso. TB incidence was measured at different intervals after HAART initiation. Cox regression models were used to identify factors associated with TB incidence.

RESULTS

We analysed a cohort of 2383 subjects with a mean follow-up period of 836 days (standard deviation +/- 443.4). TB incidence rate was highest during the first trimester of HAART; after 3 months of treatment, the total TB case incidence dropped by 60% from 5.77/100 person-years (py) to 2.23/100 py. World Health Organization clinical Stage III or IV, CD4+ T-cell count < 50 cells/microl and body mass index (BMI) < 18.5 were associated with increased risk of TB on univariate analysis. In the Cox regression, BMI < 18.5 and CD4+ T-cell count < 50 cells/microl at HAART initiation were independently associated with a two-fold higher risk of TB.

CONCLUSIONS

Delaying HAART initiation until the CD4+ T-cell count drops to <50 cells/microl significantly increases TB incidence in the first 3 months after HAART initiation. Active case finding for TB is an essential element of standard clinical care in HIV-positive patients during the initial period of HAART.

[Epidemiology and prognostic factors for sickle cell retinopathy in Ouagadougou (Burkina Faso)]

INTRODUCTION

The frequency of sickle cell disease varies from 5% to 20% in Africa.

PATIENTS AND METHOD

This retrospective study investigated 173 patients in an ambulatory setting from August 2000 to July 2006. The study included 98 women and 75 men, aged 15-62 years, with a mean age of 26.7 years.

RESULTS

Only 89 patients (71 SC and 18 SS) were seen in ophthalmology, 44 (49%) had sickle cell retinopathy with 26 (29%) cases nonproliferative and 18 cases proliferative (20%). Among the 71 SC patients, 35 (50%) had sickle cell retinopathy, with 40% the proliferative form. Of the 18 SS patients, nine had a retinopathy (50%), with four cases proliferative.

DISCUSSION

Retinopathy is a frequent complication of sickle cell disease, which can lead to blindness, and its management better accessibility to the ophthalmologic examination and preventive treatment by laser photo coagulation.

Haemoglobin C and S in natural selection against Plasmodium falciparum malaria: a plethora or a single shared adaptive mechanism?

Conclusive evidence exists on the protective role against clinical Plasmodium falciparum malaria of Haemoglobin S (beta 6Glu-->Val) and HbC (HbC; beta 6Glu-->Lys), both occurring in sub-Saharan Africa. However, the mechanism/s of the protection exerted remain/s debated for both haemoglobin variants, HbC and HbS. Recently, an abnormal display of PfEMP1, an antigen involved in malaria pathogenesis, was reported on HbAC and HbCC infected erythrocytes that showed reduced cytoadhesion and impaired rosetting in vitro. On this basis it has been proposed that HbC protection might be attributed to the reduced PfEMP1-mediated adherence of parasitized erythrocytes in the microvasculature. Furthermore, impaired cytoadherence was observed in HbS carriers suggesting for the first time a convergence in the protection mechanism of these two haemoglobin variants. We investigated the impact of this hypothesis on the development of acquired immunity against P. falciparum variant surface antigens (VSA) encoding PfEMP1 in HbC and HbS carriers in comparison with HbA of Burkina Faso. Higher immune response against a VSA panel and several malaria antigens were observed in all adaptive genotypes containing at least one allelic variant HbC or HbS in the low transmission urban area whereas no differences were detected in the high transmission rural area. In both contexts the response against tetanus toxoid was not influenced by the beta-globin genotype. Thus, these findings suggest that both HbC and HbS affect the early development of naturally acquired immunity against malaria. We reviewed the hypothesized mechanisms so far proposed in light of these recent results.

Major enzymatic factors involved in bacterial penicillin resistance in Burkina Faso

Many clinical species of bacteria were isolated from biological samples such as urines, blood and wound in Saint Camille medical centre of Ouagadougou. Among the concerned species, the most important members were Escherichia coli and Klebsiella pneumoniae. These p-lactamases producing isolates were directly screened by PCR to identify the nature of the amplified genes responsible for penicillin destroying activity. Therefore specific TEM and SHV primers were used. The PCR products were sequenced. The sequencing results indicated that the parental forms bla(TEM-1) and bla(SHV-1) were the most common determinants of beta-lactamase found, respectively in Escherichia species and Klebsiella pneumoniae. The bacterial susceptibility analysis by MICs measurement clearly correlated the presence of concerned beta-lactamase determinants and their resistance patterns. This study is part of a set of investigations carried out by our laboratory to assess the beta-lactamase incidence in the failure of beta-lactam therapy. In particular, the purpose of this study was to determine the precise nature of beta-lactamase supporting the low susceptibility of host bacteria towards penicillins.

Immunoglobulin enhancer HS1,2 polymorphism: a new powerful anthropogenetic marker

The human HS1,2 enhancer of the immunoglobulin (Ig) heavy chain 3' enhancer complex plays a central role in the regulation of Ig maturation and production. Four common alleles HS1,2-A*1, *2, *3, *4 are directly implicated with the transcription level and at least one of them, HS1, 2-A*2, seems to be related to immune disorders, such as coeliac disease, herpetiform dermatitis and Berger syndrome. Given their clinical significance it is of interest to know the distribution of HS1,2-A variants in populations from different continents, as well as to determine whether the polymorphism is associated to specific evolutionary factors. In this paper we report the distribution of the HS1,2-A polymorphism in 1098 individuals from various African, Asian and European populations. HS1,2-A*3 and HS1,2-A*4 alleles are at their highest frequencies among Africans, and HS1,2-A*2 is significantly lower in Africans in comparison with both Europeans and, to a lesser extent, Asians. Analysis of molecular variance of the allele frequencies indicates that the HS1,2-A polymorphism can be considered as a reliable anthropogenetic marker.

Plasma chitotriosidase activity in acute Plasmodium falciparum malaria

BACKGROUND

Chitotriosidase is a functional chitinase secreted by activated macrophages. It is encoded by a gene located on chromosome 1q31-32, whose mutations may be responsible for chitotriosidase deficiency, encountered in almost 6% of Caucasian population.

OBJECTIVE

This study reports firstly plasma chitotriosidase activity in African children with acute Plasmodium falciparum malaria. The chitotriosidase activity was correlated to objective parameters reflecting the status of the disease and compared with those found in healthy African children.

RESULTS

We found that plasma chitotriosidase levels are significantly increased in African children with acute malaria (185.0+/-141.0 nmol/h/ml; median 150; range 11-521) with respect to reference values obtained in age matched African children (84.4.5+/-72.8 nmol/ml/h; median 63; range 4-350) (P<0.001). Moreover the levels of chitotriosidase were higher in African children than in Caucasian children matched for age (28.86+/-18.7 nmol/h/ml; median 24; range 1-98) (P<0.0001). A remarkable significant correlation was found between plasma chitotriosidase and reticulo-endothelial activation, as judged by thrombocytopenia degree and serum ferritin level in children with acute malaria.

CONCLUSION

Based on this study, it appears that genetic and environmental features might be responsible for diversity of plasma chitotriosidase activity in black children living in Burkina Faso.

Confirmation of the potential usefulness of two human beta globin pseudogene markers to estimate gene flows to and from sub-Saharan Africans

Two polymorphic sites, -107 and -100 with respect to the "cap" site of the human beta globin pseudogene, recently discovered in our laboratory, turned out to have an ethnically complementary distribution. The first site is polymorphic in Europeans, North Africans, Indians (Hindu), and Oriental Asians, and monomorphic in sub-Saharan Africans. Conversely, the second site is polymorphic in sub-Saharan African populations and monomorphic in the aforementioned populations. Here we report the gene frequencies of these two polymorphic sites in nine additional populations (Egyptians, Spaniards, Japanese, Chinese, Filipinos, Vietnamese, Africans from Togo and from Benin, and Pygmies), confirming their ethnospecificity and, through the analysis of these two markers in Oromo and Amhara of Ethiopia (two mixed populations), their usefulness in genetic admixture studies. Moreover, we studied another marker polymorphic in sub-Saharan African populations only, a TaqI restriction fragment length polymorphism located in the same region as the present markers, demonstrating the absence of linkage disequilibrium between it and the -100 site, so that we can exclude that the information they provide is redundant.

Haemoglobin C protects against clinical Plasmodium falciparum malaria

Haemoglobin C (HbC; beta6Glu --> Lys) is common in malarious areas of West Africa, especially in Burkina Faso. Conclusive evidence exists on the protective role against severe malaria of haemoglobin S (HbS; beta6Glu --> Val) heterozygosity, whereas conflicting results for the HbC trait have been reported and no epidemiological data exist on the possible role of the HbCC genotype. In vitro studies suggested that HbCC erythrocytes fail to support the growth of P. falciparum but HbC homozygotes with high P. falciparum parasitaemias have been observed. Here we show, in a large case-control study performed in Burkina Faso on 4,348 Mossi subjects, that HbC is associated with a 29% reduction in risk of clinical malaria in HbAC heterozygotes (P = 0.0008) and of 93% in HbCC homozygotes (P = 0.0011). These findings, together with the limited pathology of HbAC and HbCC compared to the severely disadvantaged HbSS and HbSC genotypes and the low betaS gene frequency in the geographic epicentre of betaC, support the hypothesis that, in the long term and in the absence of malaria control, HbC would replace HbS in central West Africa.

The lower susceptibility to Plasmodium falciparum malaria of Fulani of Burkina Faso (west Africa) is associated with low frequencies of classic malaria-resistance genes

The gene frequencies in 1993-94 for haemoglobin S, haemoglobin C, alpha-3.7 deletional thalassaemia, G6PDA-, HLAB*5301 were estimated in Fulani, Mossi and Rimaibé ethnic groups of Burkina Faso, West Africa. The aim of the study was to verify whether the previously reported Fulani lower susceptibility to Plasmodium falciparum malaria was associated with any of these malaria-resistance genes. Similar frequencies for haemoglobin S were recorded in the 3 ethnic groups (0.024 +/- 0.008, 0.030 +/- 0.011, 0.022 +/- 0.013; in Mossi, Rimaibé and Fulani, respectively). The Mossi and Rimaibé showed higher frequencies when compared to Fulani for haemoglobin C (0.117 +/- 0.018, 0.127 +/- 0.020, 0.059 +/- 0.020), alpha-3.7 deletional thalassaemia (0.227 +/- 0.040, 0.134 +/- 0.032, 0.103 +/- 0.028), G6PDA- (0.196 +/- 0.025, 0.187 +/- 0.044, 0.069 +/- 0.025) and HLA B*5301 (0.189 +/- 0.038, 0.202 +/- 0.041, 0.061 +/- 0.024). Among Fulani the proportion of individuals not having any of these protective alleles was more than 3-fold greater than in the Mossi-Rimaibé group (56.8% vs 16.7%; P < 0.001). These findings exclude the involvement of these genetic factors of resistance to P. falciparum in the lower susceptibility to malaria of Fulani. This evidence, in association with the previously reported higher immune reactivity to malaria of Fulani, further supports the existence in this ethnic group of unknown genetic factor(s) of resistance to malaria probably involved in the regulation of humoral immune responses.

HLA class I in three West African ethnic groups: genetic distances from sub-Saharan and Caucasoid populations

Fulani of Burkina Faso (West Africa) are a particularly interesting ethnic group because of their lower susceptibility to Plasmodium falciparum malaria as compared to sympatric populations, Mossi and Rimaibé. Moreover, the occurrence of a Caucasoid component in their genetic make-up has been suggested on the basis of their physical traits and cultural traditions even though this view was not supported by genetic studies. A total of 149 unrelated subjects (53 Mossi, 47 Rimaibé and 49 Fulani) have been typed for 97 HLA class I alleles with the amplification refractory mutation system/polymerase chain reaction (ARMS/PCR) technique. Mossi and Rimaibé data were pooled since none of the 42 statistically testable alleles exhibited a significant heterogeneity. These pooled gene frequencies were found to be very different from those of Fulani: a certain (P<0.001) or a likely (0.001 <P<0.01) difference was found for 5 and 12 alleles, respectively. Four alleles (A*24, A*29, B*27, B*3701) appeared to be essentially "private" Fulani alleles with respect to the other two populations but their presence was not associated with higher resistance to P. falciparum. Our data have then been compared using chord distances (CD) with those from the literature on Africans (including Gambian Fulani) and Caucasoids. The Burkina Faso and Gambian Fulani turned out to be very different (CD=2.191). Moreover, Burkina Faso Fulani were very distant from sympatric Mossi and Rimaibé (CDs=1.912 and 1.884), whereas Gambian Fulani were similar to sympatric Mandinka and Wolof (CDs=0.412 and 0.388) to an extent comparable to that found between Mossi and Rimaibé (CD=0.555). Our study does not suggest the involvement of HLA I in the higher resistance to malaria of Fulani, and confirms a low, if any, Caucasoid component in their gene pool.