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Background The rapid expansion of antiretroviral treatment in resource-limited settings is raising concerns regarding the emergence and transmission of HIV drug resistance (HIVDR). We evaluated the extent of transmission of drug-resistant HIV strains in four Central African countries: the Republic of Congo, Central African Republic, Chad and Cameroon. Methods The World Health Organization (WHO) HIVDR threshold survey was implemented in major treatment areas in each country. Pregnant women who were aged Results The prevalence of HIVDR in Brazzaville and Bangui sites could not be classified because the eligible sample number was not reached. HIVDR prevalence was low (Conclusions The moderate HIVDR prevalence found in Yaoundé and Douala indicate that efforts should be made in Cameroon to prevent HIVDR; however, additional surveys are needed to confirm this trend. This study highlighted challenges presented by the WHO methodology, such as additional costs, workload, difficulties in acquiring even small sample numbers and the necessity for better quality assurance of HIV testing and record keeping at antenatal clinics.

Objectif : en Republique Centrafricaine, pays a transmission palustre holoendemique, le paludisme represente a lui seul 40% des motifs de consultations et constitue la premiere cause de morbidite et de mortalite. Ce pays est classe en zone C de l’Organisation mondiale de la sante (OMS) pour la resistance aux drogues antipaludiques classiques comme la chloroquine, la sulfadoxine-pyrimethamine et l’amodiaquine. C’est dans ce contexte que cette etude a pour objectif d’evaluer l’efficacite therapeutique et la praticabilite (acceptabilite) de l’artemether dans le traitement du paludisme simple chez les jeunes enfants a Bangui (RCA). Patients : il s’agit d’une etude ouverte, non comparative et transversale, effectuee chez les enfants âges de 6 mois a 5 ans traites pour paludisme simple au Centre de sante urbain (CSU) de Bede-Combattant, de mai a novembre 2005. Methode : les patients sont des enfants des deux sexes âges de 6 a 60 mois presentant une infection monospecifique a Plasmodium falciparum avec : i) une parasitemie comprise entre 2 000 et 100 000 parasites/μL dans un tableau d’acces palustre simple ; ii) une temperature axillaire superieure ou egale a 37,5 °C et inferieure a 39,5 °C. Le logiciel Epi info version 6.03® a ete utilise pour l’analyse des donnees. Resultats : parmi 53 dossiers de patients inclus, 49 ont pu etre analyses. Une reponse clinique et parasitologique adequate (RCPA) a ete obtenue chez 47 d’entre eux, soit 96 % ; un echec therapeutique precoce (ETP) a ete observe chez un patient (a J2), et un echec parasitologique tardif (EPT) defini a J14, est survenu chez un patient ; au total, on a observe 4 % d’echecs precoces ou tardifs. La tolerance a ete excellente. Conclusion : l’artemether etait bien tolere. Cette molecule constitue une alternative efficace et sure pour le traitement du paludisme simple a P. falciparum de l’enfant en RCA.

Summary: Drug resistance to Plasmodium falciparum contributes to major health problems in central Africa and, as a consequence, poverty. We have analyzed the efficacy of three currently available antimalarial drugs to treat symptomatic, uncomplicated P. falciparum malaria in semiimmune adults living in Bangui, Central Republic of Africa. 210 consecutive individuals were enrolled in the survey, of which 45 were excluded. Those having received dihydroartemisin proved significantly less parasitemic than those having received quinine per os or sulfadoxin-pyrimethamin (χ2 = 16.93 ; p < 0.05), and 75 % recovered in two days compared to 57 and 44 %, respectively. The 25 % who did not recover benefited from a second cure with dihydroartemisin, which proved 100 % efficient. The most accurate protocol remains to be established by analyzing clinical and parasitological data and taking into account the economics of the country.

Transmission of malaria in the Central African Republic is holoendemic. The disease accounts for 40% of medical consultations and is the leading cause of morbidity and mortality. Central African Republic is classified by WHO in zone C for resistance to traditional anti-malaria drugs such as chloroquine, sulfadoxine-pyrimethamine, and amodiaquine. In this setting, our study sought to evaluate the therapeutic effectiveness and the feasibility (acceptability) of artemether in the treatment of uncomplicated malaria in young children in Bangui.This non-comparative, cross-sectional, open study included children aged from 6 months to 5 years of age treated for uncomplicated malaria at the Urban Health Center (CSU) of Bédé-Combatant from May through November 2005. All children had a specific Plasmodium falciparum infection and both parasitemia ranging from 2,000 to 100,000 parasites/microL in uncomplicated malaria and an axillary temperature of 37.5 degrees C or higher but lower than 39.5 degrees C. Epi info software, version 6.03, was used for the data analysis.The study included 53 children, only 49 of whom could be analysed. An adequate clinical and parasitological response (ACPR) was obtained for 47 (96%), early therapeutic failure was detected for 1 patient (on D2), and late parasitological failure on D14 for another. On the whole, only 4% could be qualified as early or late treatment failure. Tolerance was excellent.Artemether was well tolerated. This agent is an effective and safe alternative for the treatment of uncomplicated P. falciparum malaria in children in the Central African Republic.

Cytophilic antibodies (Abs) play a critical role in protection againstPlasmodium falciparumblood stages, yet little is known about the parameters regulating production of these Abs. We used an in vitro culture system to study the subclass distribution of antigen (Ag)-specific immunoglobulin G (IgG) produced by peripheral blood mononuclear cells (PBMCs) from individuals exposed toP. falciparumor unexposed individuals. PBMCs, cultivated with or without cytokines and exogenous CD40/CD40L signals, were stimulated with a crude parasite extract, recombinant vaccine candidates derived from conserved Ags (19-kDa C terminus of merozoite surface protein 1 [MSP119], R23, and PfEB200), or recombinant Ags derived from the polymorphic Ags MSP1 block 2 and MSP2. NoP. falciparum-specific Ab production was detected in PBMCs from unexposed individuals. PBMCs from donors exposed frequently toP. falciparuminfections produced multiple IgG subclasses when they were stimulated with the parasite extract but usually only one IgG subclass when they were stimulated with a recombinant Ag. Optimal Ab production required addition of interleukin-2 (IL-2) and IL-10 for all antigenic preparations. The IgG subclass distribution was both donor and Ag dependent and was only minimally influenced by the exogenous cytokine environment. In vitro IgG production and subclass distribution correlated with plasma Abs to some Ags (MSP119, R23, and MSP2) but not others (PfEB200 and the three MSP1 block 2-derived Ags). Data presented here suggest that intrinsic properties of the protein Ag itself play a major role in determining the subclass of the Ab response, which has important implications for rational design of vaccine delivery.

Cord blood B cells obtained from neonates of healthy Senegalese mothers were assayed in vitro for their capacity to fully differentiate and secrete immunoglobulins (Ig) of various classes and subclasses. Stimulation of mononuclear cells with SAC particles or anti-μ antibodies in the presence of IL-4, or with IL-2 and IL-10 induced a strong production of IgG, provided that an additional CD40/CD40L signal was present, in contrast to adult cell cultures. Cord blood mononuclear cells differentially stimulated with various cytokines in order to lead to Ig heavy chain switching and production of the various classes/subclasses consistently produced IgG1, IgG3, IgG4, IgE and IgA. This system has been applied to immune cells from African neonates that have not been extensively studied previously. Estimation of Ig production as OD ratios could be applied to cultures where cord blood B cells are stimulated with defined antigens of human pathogens to which the fetus immune system was primed in utero.

In malaria endemic areas, pregnancy is assumed to be associated with a specific reduction in immunity to Plasmodium falciparum malaria. To understand some of the mechanisms which underlie such a poor immunity, we have attempted to examine the frequency and distribution of IgM and IgG antibodies to a crude antigenic extract of parasitized erythrocytes and to the merozoite surface protein-1 (MSP1), in a population of mothers compared to control non-pregnant women, all living in Dakar and suburbs. Specifically, this work describes: (i) the responses of mothers and control women; (ii) the balance between IgM and IgG responses; and (iii) responses to malarial antigen and to MSP1. An unexpected balance between P. falciparum-specific IgM and IgG is shown, associated with a substantial increase in anti-MSP1 IgM, and a decrease in anti-MSP1 IgG in parturients.