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Background: There is no recent epidemiological data on HIV infection in Gabon, particularly in pregnant women. To close this gap, an HIV-prevalence survey was conducted among Gabonese pregnant women, followed by a cross-sectional case-control study in which the prevalence of various co-infections was compared between HIV-positive and HIV-negative pregnant women., Methods: Between 2018 and 2019, data for the HIV-prevalence survey were collected retrospectively in 21 Gabonese antenatal care centres (ANCs). Subsequently, for the prospective co-infection study, all HIV-positive pregnant women were recruited who frequented the ANC in Lambaréné and a comparator sub-sample of HIV-negative pregnant women was recruited; these activities were performed from February 2019 to February 2020. The mean number of co-infections was ascertained and compared between HIV-positive and HIV-negative women. Additionally, the odds for being co-infected with at least one co-infection was evaluated and compared between HIV-positive and HIV-negative women., Results: HIV-positivity was 3.9% (646/16,417) among pregnant women. 183 pregnant women were recruited in the co-infection study. 63% of HIV-positive and 75% of HIV-negative pregnant women had at least one co-infection. There was a trend indicating that HIV-negative women were more often co-infected with sexually transmitted infections (STIs) than HIV-positive women [mean (standard deviation, SD): 2.59 (1.04) vs 2.16 (1.35), respectively; P = 0.056]; this was not the case for vector-borne infections [mean (SD): 0.47 (0.72) vs 0.43 (0.63), respectively; P = 0.59]., Conclusions: Counterintuitively, the crude odds for concomitant STIs was lower in HIV-positive than in HIV-negative women. The change of magnitude from the crude to adjusted OR is indicative for a differential sexual risk factor profile among HIV-positive and HIV-negative women in this population. This might potentially be explained by the availability of sexual health care counselling for HIV-positive women within the framework of the national HIV control programme, while no such similar overall service exists for HIV-negative women. This highlights the importance of easy access to sexual healthcare education programmes for all pregnant women irrespective of HIV status., (© 2023. The Author(s).)

Background: Asthma is not well investigated in equatorial Africa and little is known about the disease-associated allergen molecules recognized by IgE from patients in this area. The aim was to study the molecular IgE sensitization profile of asthmatic children and young adults in a semi-rural area (Lambaréné) of an equatorial African country (Gabon), to identify the most important allergen molecules associated with allergic asthma in equatorial Africa., Methods: Fifty-nine asthmatic patients, mainly children and few young adults, were studied by skin prick testing to Dermatophagoides pteronyssinus (Der p), D. farinae (Der f), cat, dog, cockroach, grass, Alternaria and peanut. Sera were obtained from a subset of 35 patients, 32 with positive and 3 with negative skin reaction to Der p and tested for IgE reactivity to 176 allergen molecules from different allergen sources by ImmunoCAP ISAC microarray technology and to seven recombinant Blomia tropicalis (Blo t) allergens by IgE dot blot assay., Results: Thirty-three of the 59 patients (56%) were sensitized to Der p and 23 of them (39%) were also sensitized to other allergen sources, whereas 9 patients (15%) were only sensitized to allergen sources other than Der p. IgE serology analyses (n=35) showed high IgE-binding frequencies to the Blo t allergens Blo t 5 (43%), Blo t 21 (43%) and Blo t 2 (40%), whereas the Der p allergens rDer p 2, rDer p 21 and rDer p 5 (34%, 29% and 26%) were less frequently recognized. Only few patients showed IgE reactivity to allergens from other allergen sources, except to allergens containing carbohydrate determinants (CCDs) or to wasp venom allergens (i.e., antigen 5)., Conclusion: Our results thus demonstrate that IgE sensitization to mite allergens is very prevalent in asthmatics in Equatorial Africa with B. tropicalis allergen molecules representing the most important ones associated with allergic asthma., Competing Interests: Author RV has received research grants from HVD Life Science, Vienna Austria, WORG Pharmaceuticals, Hangzhou, China and Viravaxx, Vienna, Austria and serves as a consultant for WORG and Viravaxx. Author CL is currently employee of Macro Array Diagnostics, Vienna, Austria. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Pauli, Wurmser, Roos, Kokou, Huang, D’souza, Lupinek, Zakzuk, Regino, Acevedo, Caraballo, Vrtala and Valenta.)

Objective: Routinely generated surveillance data are important for monitoring the effectiveness of MDR-TB control strategies. Incidence of rifampicin-resistant tuberculosis (RR-TB) is a key indicator for monitoring MDR-TB., Methods: In a longitudinal nationwide retrospective study, 8 years (2014-2021) of sputum samples from presumptively drug-resistant tuberculosis patients from all regions of Gabon were referred to the national tuberculosis reference laboratory. Samples were analysed using GeneXpert MTB/RIF and Genotype MTBDRsl version 2/Line Probe Assay., Results: Of 3057 sputum samples from presumptive tuberculosis patients, both from local hospital and from referral patients, 334 were RR-TB. The median patient age was 33 years (interquartile range 26-43); one third was newly diagnosed drug-resistant tuberculosis patients; one-third was HIV-positive. The proportion of men with RR-TB was significantly higher than that of women (55% vs 45%; p < 0.0001). Patients aged 25-35 years were most affected (32%; 108/334). The cumulative incidence of RR-TB was 17 (95% CI 15-19)/100,000 population over 8 years. The highest incidences were observed in 2020 and 2021. A total of 281 samples were analysed for second-line drug resistance. The proportions of study participants with MDR-TB, pre-XDR-TB and XDR-TB were 90.7% (255/281), 9% (25/281) and 0.3% (1/281), respectively. The most-common mutations in fluoroquinolones resistance isolates was gyrA double mutation gyrA MUT3B and MUT3C (23%; 4/17). Most (64%; 6/8) second-line injectable drugs resistance isolates were characterised by missing both rrs WT2 and MUT2 banding., Conclusion: The increasing incidence of MDR-TB infection in Gabon is alarming. It is highest in the 25-35 years age category. The incidence of MDR-TB infection in treatment-naïve patients calls for case finding and contact tracing strategy improvement., (© 2022. The Author(s).)

Background: Group A ß-hemolytic streptococcus (GABHS) is a leading pathogen worldwide and post-streptococcal sequelae is a major cause of morbidity and mortality in resource-limited countries. The M protein (coded by the emm gene) is a key virulence factor and a component of GABHS vaccine candidates. As data on BHS in Central Africa are scarce, antibiotic resistance, emm diversity and potential vaccine coverage were investigated., Methods: In a prospective cross-sectional study, 1014 Gabonese were screened for streptococcal throat carriage, tonsillopharyngitis and pyoderma by throat and skin smear tests. All BHS were isolated, species were identified and analysis of antibiotic resistance, emm types and emm clusters was performed., Results: One hundred sixty-five BHS were detected, comprising 76 GABHS, 36 group C ß-hemolytic streptococcus (GCBHS) and 53 group G ß-hemolytic streptococcus (GGBHS) in 140 carrier, 9 tonsillopharyngitis and 16 pyoderma isolates. Eighty percentage of GABHS, 78% of GCBHS and 79% of GGBHS were tetracycline resistant. Forty-six emm types were identified. GABHS emm58, emm65 and emm81 were most prevalent (26%). Emm diversity of GABHS was the highest, GCBHS and GGBHS were less divers. Every second GABHS, every third GCBHS and every tenth GGBHS carrier was colonized with emm types detected in tonsillopharyngitis or pyoderma isolates., Conclusions: Tetracycline resistance and emm type diversity was high among BHS carriers in Gabon with a potential coverage of 58% by the 30-valent GABHS vaccine. A relevant overlap of carrier emm types with emm types found in tonsillopharyngitis and pyoderma characterizes a shared pool of circulating BHS strains., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved..)

The aim of this study was to analyze the population dynamics of Streptococcus pneumoniae in a remotely living African Pygmy population. The same pygmy population (Gabon) was prospectively screened for nasopharyngeal S. pneumoniae colonization in 2011 (n = 103), 2013 (n = 104) and 2017 (n = 107). Non-duplicate isolates (n = 126) were serotyped and tested for antimicrobial resistance (broth microdilution). At the three sampling time points, resistance rates were highest for tetracycline (36-58%), followed by penicillin (parenteral, meningitis-breakpoints, 6-39%) and chloramphenicol (3-15%). The majority of isolates was non-typeable (NT, n = 18/126, 14.3%) followed by serotype 6B (n = 17/126, 13.5%), 21 and 15A (n = 9/126, 7.1%, each). The distribution of serotypes was highly dynamic as only three serotypes (14, 17F, NT) were detected during all three visits. Resistance rates and serotypes of nasopharyngeal S. pneumoniae markedly changed in the remote Babongo population. This rapid change in serotypes could challenge the selection of pneumococcal vaccine., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Malaria caused by the apicomplexan parasite Plasmodium falciparum has served as a strong evolutionary force throughout human history, selecting for red blood cell polymorphisms that confer innate protection against severe disease. Recently, gain-of-function mutations in the mechanosensitive ion channel PIEZO1 were shown to ameliorate Plasmodium parasite growth, blood-brain barrier dysfunction, and mortality in a mouse model of malaria. In humans, the gain-of-function allele PIEZO1 E756del is highly prevalent and enriched in Africans, raising the possibility that it is under positive selection due to malaria. Here we used a case-control study design to test for an association between PIEZO1 E756del and malaria severity among children in Gabon. We found that the E756del variant is strongly associated with protection against severe malaria in heterozygotes. In subjects with sickle cell trait, heterozygosity for PIEZO1 E756del did not confer additive protection and homozygosity was associated with an elevated risk of severe disease, suggesting an epistatic relationship between hemoglobin S and PIEZO1 E756del. Using donor blood samples, we show that red cells heterozygous for PIEZO1 E756del are not dehydrated and can support the intracellular growth of P. falciparum similar to wild-type cells. However, surface expression of the P. falciparum virulence protein PfEMP-1 was significantly reduced in infected cells heterozygous for PIEZO1 756del, a phenomenon that has been observed with other protective polymorphisms, such as hemoglobin C. Our findings demonstrate that PIEZO1 is an important innate determinant of malaria susceptibility in humans and suggest that the mechanism of protection may be related to impaired export of P. falciparum virulence proteins., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)

The causes of infections in pediatric populations differ between age groups and settings, particularly in the tropics. Such differences in epidemiology may lead to misdiagnosis and ineffective empirical treatment. Here, we investigated the current spectrum of pathogens causing febrile diseases leading to pediatric hospitalization in Lambaréné, Gabon. From August 2015 to March 2016, we conducted a prospective, cross-sectional, hospital-based study in a provincial hospital. Patients were children ≤ 15 years with fever ≥ 38 °C and required hospitalization. A total of 600 febrile patients were enrolled. Malaria was the main diagnosis found in 52% (311/600) patients. Blood cultures revealed septicemia in 3% (17/593), among them four cases of typhoid fever. The other causes of fever were heterogeneously distributed between both bacteria and viruses. Severe infections identified by Lambaréné Organ Dysfunction Score (LODS) were also most often caused by malaria, but children with danger signs did not have more coinfections than others. In 6% (35/600) of patients, no pathogen was isolated. In Gabon, malaria is still the major cause of fever in children, followed by a bacterial and viral disease. Guidelines for both diagnosis and management should be tailored to the spectrum of pathogens and resources available locally.

Background: Malaria remains a major public health problem, affecting mainly low-and middle-income countries. The management of this parasitic disease is challenged by ever increasing drug resistance. This study, investigated the therapeutic efficacy, tolerability and safety of artemether-lumefantrine (AL) and artesunate-amodiaquine (AS-AQ), used as first-line drugs to treat uncomplicated malaria in Lambaréné, Gabon., Methods: A non-randomized clinical trial was conducted between October 2017 and March 2018 to assess safety, clinical and parasitological efficacy of fixed-doses of AL and AS-AQ administered to treat uncomplicated Plasmodium falciparum malaria in children aged from 6 months to 12 years. After 50 children were treated with AL, another 50 children received ASAQ. The 2009 World Health Organization protocol for monitoring of the efficacy of anti‑malarial drugs was followed. Molecular markers msp1 and msp2 were used to differentiate recrudescence and reinfection. For the investigation of artemisinin resistant markers, gene mutations in Pfk13 were screened., Results: Per-protocol analysis on day 28 showed a PCR corrected cure rate of 97% (95% CI 86-100) and 95% (95% CI 84-99) for AL and AS-AQ, respectively. The most frequent adverse event in both groups was asthenia. No mutations in the kelch-13 gene associated with artemisinin resistance were identified. All participants had completed microscopic parasite clearance by day 3 post-treatment., Conclusion: This study showed that AL and AS-AQ remain efficacious, well-tolerated, and are safe to treat uncomplicated malaria in children from Lambaréné. However, a regular monitoring of efficacy and a study of molecular markers of drug resistance to artemisinin in field isolates is essential. Trial registration ANZCTR, ACTRN12616001600437. Registered 18 November, http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12616001600437p&isBasic=True.

Background: In a previous study, severe and cerebral malaria have been connected with acute cochlear malfunction in children, demonstrated by a decrease of transitory evoked otoacoustic emissions (TEOAEs) reproducibility. This study aims to determine whether cochlear malfunction persists for 4 years after recovery from severe malaria in a subset of the previous study's collective. Follow-up TEOAEs were performed on site (CERMEL, Hôpital Albert Schweitzer, Lambaréné, Gabon) or at the participants' homes; 33 out of 90 participants included in the initial investigation by Schmutzhard et al. could be retrieved and were re-examined, 31/33 could be included. Of the 57 missing participants, 51 could not be contacted, 1 had moved away, 4 refused to cooperate, and 1 had died., Methods: As in the initial investigation, participants of this prospective follow-up study were subjected to TEOAE examination on both ears separately. A wave correlation rate of > 60% on both ears was considered a "pass"; if one ear failed to pass, the examination was considered a "fail". The results were compared to the primary control group. Additionally, a questionnaire has been applied focusing on subsequent malaria infections between the primary inclusion and follow-up and subjective impairment of hearing and/or understanding., Results: The cohort's mean age was 9 years, 14 children were female, 18 male. 31 had been originally admitted with severe, one with cerebral malaria. 83.8% of participants (n = 26) presented with a TEOAE correlation rate of > 60% on both ears (the cut-off for good cochlear function); in the control group, 92.2% (n = 83) had passed TEOAE examination on both ears. Recurrent severe malaria was associated with a worse TEOAE correlation rate. Age at infection and gender had no influence on the outcome., Conclusions: Cochlear malfunction seems to be persistent after 4 years in more than 16% of children hospitalized for malaria. In a healthy control group, this proportion was 7.8%. Yet, the severity of the initial TEOAE-decrease did not predict a worse outcome.

The minimally invasive autopsy (MIA), an innovative approach for obtaining post-mortem samples of key organs, is increasingly being recognized as a robust methodology for cause of death (CoD) investigation, albeit so far limited to pilot studies and research projects. A better understanding of the real causes of death in middle- and low-income countries, where underlying causes of death are seldom determined, would allow improved health planning, more targeted prioritization of available resources and the implementation of coherent public health policies. This paper discusses lessons learnt from the implementation of a Feasibility and Acceptability (F&A) study evaluating the MIA approach in five countries: Gabon, Kenya, Mali, Mozambique and Pakistan. This article reports the methodological choices made to document sociocultural and religious norms around death, to examine community and relatives' attitudes and perceptions towards MIA, and to identify factors motivating the MIA's acceptance and refusal. We used ethnography, grounded theory and framework method approaches. In-depth and semi-structured interviews and focus group discussions with key informants, including next of kin of deceased individuals and healthcare providers, were conducted. Participant observation and direct observation of procedures and ceremonies around death were organized in all study sites. In Mozambique, MIA procedures were observed and case studies conducted. The implementation of this F&A protocol has provided critical lessons that could facilitate the future implementation of post-mortem procedures for CoD investigation. These include the need for early community engagement, staff training and preparedness, flexibility to adapt the protocol, gathering qualitative data from diverse sources, and triangulation of the data. We have applied a rigorous, effective and culturally sensitive methodological approach to assess the F&A of MIA in resource-constrained settings. We strongly recommend that such an approach is applied in settings where MIAs or similar post-mortem sensitive procedures are to be introduced.

Background: At times, ultrasound is not readily available in low resource countries in Africa for accurate determination of gestational age, so using alternative methods is pivotal during pregnancy. These assessments are used to aid the risk analysis for an infant and management strategies for premature delivery, if necessary. Currently, date of last menstrual period, fundal height measurements, and the New Ballard Score are commonly used in resource-limited settings. However, concordance of these measures is unknown for sub-Saharan Africa. We obtained data from an open-label randomized controlled trial, to assess the concordance of these alternative assessment methods. The purpose of our study was to determine the agreement between these alternative methods when used in sub-Saharan African populations., Methods: A total of 4,390 pregnant women from Benin, Gabon, Mozambique and Tanzania were included in our analysis. The assessment methods compared were: 1) reported last menstrual period, 2) symphysis-fundal height measurement, and 3) the New Ballard Score. The Bland-Altman method and intraclass correlation coefficient (ICC) were used to test the degree of agreement. Survival range gestational age, used as an inclusion criterion for further analysis, was from 22 to 44 weeks., Findings: Plots showed a lack of agreement between methods and the 95% limits of agreement too wide to be clinically useful. ICC = 0.25 indicated poor agreement. A post-hoc analysis, restricted from 32 to 42 weeks, was done to check for better agreement in this near-term population. The plots and ICC = 0.16 still confirmed poor agreement., Conclusion: The alternative assessments do not result in comparable outcomes and discrepancies are far beyond the clinically acceptable range. Last menstrual period should not be used as the only estimator of gestational age. In the absence of reliable early ultrasound, symphysis-fundal height measurements may be most useful during pregnancy for fetal risk assessment and the New Ballard Score after delivery as a confirmation of these estimations and for further neonatal management. However, promotion of portable ultrasound devices is required for accurate assessment of gestational age in sub-Sahara Africa., Competing Interests: The authors have declared that no competing interests exist.

Artemisinin-based combination therapies are recommended as first-line agents for treating uncomplicated Plasmodium falciparum malaria. Ferroquine, a 4-aminoquinolone, is a novel long-acting combination partner for fast-acting drugs like artesunate (AS). We did a small phase 2a, multicenter, open-label, safety-focused dose-ranging randomized study of ferroquine at three African hospitals: two Gabonese and one Kenyan. We recruited adult men with symptomatic uncomplicated P. falciparum monoinfection. Four escalating doses of ferroquine (100, 200, 400, and 600 mg) were assessed in sequence, versus an amodiaquine comparator. After a 2:1 randomization (block size three, equating to N = 12 for each ferroquine dose and N = 6 for each of four amodiaquine comparator groups) patients received daily for three consecutive days, either ferroquine + AS (200 mg/day) or amodiaquine (612 mg/day) + AS (200 mg/day). Safety, electrocardiograms, parasite clearance times, efficacy, and pharmacokinetics were assessed to day 28. Seventy-two patients were randomized. Ferroquine + AS showed generally mild increases (Grade 1 toxicity) in alanine aminotransferase (ALT) levels with a dose trend starting at 400 mg. There were two Grade 2 ALT events: one patient receiving 200 mg (3.8 upper limit of normal [ULN], day 7) and one receiving 600 mg (3.3 ULN, day 14), both without increased bilirubin. One ferroquine 100 mg + AS patient after one dose was withdrawn after developing a QTcF interval prolongation > 60 milliseconds over baseline. Parasitemias in all patients cleared quickly, with no recurrence through day 28. Hepatic, as well as cardiac, profiles should be monitored closely in future trials. (ClinicalTrials.gov: NCT00563914).

Background: HIV infection is accompanied by various systemic host responses, including activation of coagulation and the vascular endothelium. We sought to determine the impact of opportunistic coinfections in a central African setting., Methods: This prospective study included 98 HIV-infected individuals in Gabon initiating combination antiretroviral therapy (cART) and followed them up for 6 months. Patients were stratified according to the presence of active tuberculosis (TB; n=19), mucocutaneous opportunistic infection (n=9) or no opportunistic infection (n=70). HIV-uninfected subjects were included as controls (n=32). Plasma concentrations of 14 markers of coagulation, endothelial activation, extracellular matrix formation and tissue damage were measured with a multiplex assay at baseline and months 3 and 6 after cART initiation., Results: HIV-infected patients showed elevated plasma levels of all biomarkers measured with exception of protein C, which was reduced. Concurrent TB was only associated with elevated concentrations of D-dimer, metallopeptidase inhibitor 1 and Tenascin-C. Mucocutaneous coinfection did not alter HIV-associated responses. Most markers measured declined but remained elevated despite response to cART., Conclusions: HIV infection is associated with systemic pro-coagulant, vascular and damage responses. In an ambulatory setting, concurrent opportunistic infections have little if any influence on these responses and normalization is incomplete after response to cART. This suggests that these responses are mainly driven by HIV-associated immune activation and less so by opportunistic infections.

Background: We recently described the effect of a single-dose antihelminthic treatment on vaccine immunogenicity to a seasonal influenza vaccine. Here we report the effect of antihelminthics on the immunogenicity of a meningococcal vaccine and a cholera vaccine in primary school children living in Lambaréné, Gabon. Since infection with helminths remains a major public health problem and the influence on cognitive and physical development as well as the immunomodulatory effects are well established, we investigated if a single-dose antihelminthic treatment prior to immunization positively influences antibody titers and vaccine-specific memory B-cells., Methods: In this placebo-controlled, double-blind trial the effect of a single-dose antihelminthic treatment prior to immunization with a meningococcal as well as with a cholera vaccine was investigated. Anti-meningococcal antibodies were assessed by serum bactericidal assay, cholera vaccine-specific antibody titers by Enzyme-linked Immunosorbent Assay (ELISA) at baseline (Day 0; vaccination), four weeks (Day 28) and 12weeks (Day 84) following vaccination. Meningococcal and cholera vaccine-specific memory B-cells were measured at Day 0 and 84 by vaccine-specific Enzyme-linked Immunospot (ELISpot) assay. The helminth burden of the participants was assessed four weeks before vaccination (Day -28) and at Day 84 by the Merthiolate-Iodine-Formaldehyde technique., Results: Out of 280 screened school children, 96 received a meningococcal vaccine and 89 a cholera vaccine following allocation to either the single-dose antihelminthic treatment group or the placebo group. Bactericidal antibody titers increased following immunization with the meningococcal vaccine at Day 28 and Day 84 in 68 participants for serogroup A, and in 80 participants for serogroup C. The cholera vaccine titers increased in all participants with a peak at Day 28. The number of memory B-cells increased following vaccination compared to baseline. There was no statistically significant difference in antibody and B-cell response between children receiving albendazole compared to those receiving placebo., Conclusion: A single-dose treatment with albendazole prior to immunization had no effect on meningococcal or cholera vaccine immunogenicity in our study population., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: There is a need for accurate and field-applicable instruments for the evaluation of the quality of anti-malarial drugs. The aim of this study was to determine the diagnostic accuracy of the NanoRam(®), a handheld Raman spectrometer (RS), to identify anti-malarial drugs., Methods: In total, 289 anti-malarial drugs collected in a randomized field survey in Gabon were evaluated. The samples were compared with authentic products as supplied by the official manufacturer. To determine the sensitivity and specificity of the handheld NanoRam(®) spectrometer in the identification of anti-malarial drugs, a two-gate reversed-flow design was applied. The standards for reporting of diagnostic accuracy studies (STARD) were followed. The index test was the handheld RS. The reference test standards were thin layer chromatography and high performance liquid chromatography with ultraviolet photo diode array detection., Results: The sensitivity [95% confidence interval (95% CI)] and specificity of the RS to correctly identify an anti-malarial drug were 100% (95% CI 94.9-100%) and 96% (95% CI 92.3-99.0%), respectively. The RS could not differentiate between different batches of the same product or different manufacturers of the same product. Intra-observer agreement for 289 samples was 100%. The average time to conduct the RS was 15 s per sample compared to 45 min per sample for TLC., Conclusion: The handheld RS holds promise as an easy-to-use, quick and field-applicable instrument for the evaluation of quality of anti-malarial drugs, potentially empowering pharmacists, drug inspectors and medical regulatory authorities. Trial registration NTR4341 (Dutch Trial Registry).

Neonatal invasive disease due to Streptococcus agalactiae is life threatening and preventive strategies suitable for resource limited settings are urgently needed. Protective coverage of vaccine candidates based on capsular epitopes will relate to local epidemiology of S. agalactiae serotypes and successful management of critical infections depends on timely therapy with effective antibiotics. This is the first report on serotype distribution and antimicrobial susceptibility of S. agalactiae in pregnant women from a Central African region. Serotypes V, III, and Ib accounted for 88/109 (81%) serotypes and all isolates were susceptible to penicillin and clindamycin while 13% showed intermediate susceptibility to erythromycin.

Background: Recent studies alluded to the alarming scale of poor anti-malarial drug quality in malaria-endemic countries, but also illustrated the major geographical gaps in data on anti-malarial drug quality from endemic countries. Data are particularly scarce from Central Africa, although it carries the highest burden of malaria. The aim of this medicine quality field survey was to determine the prevalence of poor-quality anti-malarial drugs in Gabon., Methods: A field survey of the quality of anti-malarial drugs in Gabonese pharmacies was conducted using the Global Pharma Health Fund Minilab(®) tests, following the Medicine Quality Assessment Reporting Guidelines. Anti-malarial drugs were purchased randomly from selected pharmacies in Gabon. Semi-quantitative thin-layer chromatography (TLC) and disintegration testing were carried out to measure the concentration of active pharmaceutical ingredients (APIs). The samples failing the TLC test were analysed by high-performance liquid chromatography. Following the collection of anti-malarial drugs, a street survey was conducted to understand where people purchase their anti-malarial drugs., Results: A total of 432 samples were purchased from 41 pharmacies in 11 cities/towns in Gabon. The prevalence of poor-quality anti-malarial drugs was 0.5% (95% CI 0.08-1.84%). Two out of 432 samples failed the MiniLab(®) semi-quantitative TLC test, of which a suspected artemether-lumefantrine (AL) sample was classified as falsified and one sulfadoxine-pyrimethamine (SP) sample as substandard. High performance liquid chromatography with ultraviolet photo diode array detection analysis confirmed the absence of APIs in the AL sample, and showed that the SP sample did contain the stated APIs but the amount was half the stated dose. Of the people interviewed, 92% (187/203) purchased their anti-malarial drugs at a pharmacy., Conclusion: Using the GPHF Minilab(®), the prevalence of poor-quality anti-malarial drugs is far lower than anticipated. The findings emphasize the need for randomized and robust sampling methods in order to collect representative data on anti-malarial drug quality., Trial Registration: NTR4341 (Dutch Trial Registry).

Background: Helminth infections are a major public health problem, especially in the tropics. Infected individuals have an altered immune response with evidence that antibody response to vaccination is impaired. Hence, treatment of helminth infections before vaccination may be a simple intervention to improve vaccine immunogenicity. In the present study we investigated whether a single-dose antihelminthic treatment influences antibody responses to a seasonal influenza vaccine in primary school children living in Gabon, Central Africa., Methods: In this placebo-controlled double-blind trial conducted in Gabon the effect of a single-dose antihelminthic treatment with 400 mg albendazole versus a placebo one month prior to immunization with a seasonal influenza vaccine was investigated. Antiviral antibody titers against all three vaccine strains were assessed by haemagglutination inhibition (HI) test at baseline (Day 0; vaccination) and four weeks (Day 28) as well as 12 weeks (Day 84) following vaccination. Vaccine-specific memory B-cell response was measured at Day 0 and Day 84 by vaccine-specific Enzyme-linked Immunospot (ELISpot) assay. The trial is registered with the Pan African Clinical Trials Registry (PACTR) (PACTR201303000434188)., Results: 98 school children aged 6-10 years were randomly allocated to receive either antihelminthic treatment or placebo and were vaccinated one month after the treatment. The prevalence of helminths at baseline was 21%. Vaccine-specific HI titers against at least one of the three vaccine strains increased at Day 28 and Day 84 in all participants. HI titers against both influenza A strains as well as memory B-cell response were modestly higher in the antihelminthic treated group compared to the placebo group but the difference was not statistically significant. Total but not specific IgA was elevated in the antihelminthic treated group compared to the control group at Day 28., Conclusion: In our setting antihelminthic treatment had no significant effect on influenza vaccine immunogenicity. A trend towards better antiviral and vaccine immunogenicity in the antihelminthic treated group encourages studies to be conducted with alternative treatment schedules or in populations with a higher helminth burden.

In order to minimize risks of pathogen transmission with the development of ecotourism in Gabon, a seasonal inventory has been performed in five contrasted biotopes in Ivindo (INP) and Moukalaba-Doudou (MDNP) National Parks. A total of 10,033 hematophagous flies were captured. The Glossinidae, with six different species identified, was the most abundant group and constitutes about 60% of the captured flies compared to the Stomoxys (6 species also identified) and Tabanidae with 28% and 12%, respectively. The Glossinidae showed a higher rate of capture in primary forest and in research camps. In INP, the Stomoxys showed a higher rate of capture in secondary forest and at village borders, whereas in MDNP the Stomoxys were captured more in the savannah area. Thus, each fly group seemed to reach maximum abundance in different habitats. The Glossinidae were more abundant in primary forest and near research camps while Stomoxys were more abundant in secondary forest and savannah. The Tabanidae did not show a clear habitat preference., (© P.Y. Bitome Essono et al., published by EDP Sciences, 2015.)

Objectives: Streptococcus agalactiae constitutes an important cause of neonatal infections in sub-Saharan Africa. Sulfadoxine/pyrimethamine-the current intermittent preventive treatment of malaria in pregnancy (IPTp)-has proven in vitro activity against group B Streptococcus (GBS). Because of specific drug resistance to sulfadoxine/pyrimethamine, mefloquine-an antimalarial without in vitro activity against GBS-was evaluated as a potential alternative. This study assessed the potential of sulfadoxine/pyrimethamine-IPTp to reduce the prevalence of GBS colonization in pregnant women in Gabon when compared with the inactive control mefloquine-IPTp., Methods: Pregnant women participating in a randomized controlled clinical trial evaluating mefloquine-IPTp versus sulfadoxine/pyrimethamine-IPTp were invited to participate and recto-vaginal swabs were collected at delivery for detection of GBS colonization. Prevalence of recto-vaginal GBS colonization was compared between IPTp regimens and risk factor and birth outcome analyses were computed., Results: Among 549 participants, 106 were positive for GBS colonization at delivery (19%; 95% CI = 16%-23%). Prevalence of maternal GBS colonization showed no significant difference between the two IPTp regimens (mefloquine-IPTp: 67 of 366 women = 18%; 95% CI = 14%-22%; sulfadoxine/pyrimethamine-IPTp: 39 of 183 women = 21%; 95% CI = 15%-27%). Risk factor analysis for GBS colonization demonstrated a significant association with illiteracy (adjusted OR = 2.03; 95% CI = 1.25-3.30). GBS colonization had no impact on birth outcome, anaemia at delivery, gestational age and birth weight., Conclusions: Sulfadoxine/pyrimethamine did not reduce colonization rates when used as the IPTp drug during pregnancy. Illiteracy was associated with GBS colonization., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Tropheryma whipplei is the causative agent of Whipple's disease and has been detected in stools of asymptomatic carriers. Colonization has been associated with precarious hygienic conditions. There is a lack of knowledge about the epidemiology and transmission characteristics on a population level, so the aim of this study was to determine the overall and age-specific prevalence of T. whipplei and to identify risk factors for colonization. This molecular epidemiological survey was designed as a cross-sectional study in a rural community in Central African Gabon and inhabitants of the entire community were invited to participate. Overall prevalence assessed by real-time PCR and sequencing was 19.6% (95% CI 16-23.2%, n=91) in 465 stool samples provided by the study participants. Younger age groups showed a significantly higher prevalence of T. whipplei colonization ranging from 40.0% (95% CI 27.8-52.2) among the 0-4 year olds to 36.4% (95% CI 26.1-46.6) among children aged 5-10 years. Prevalence decreased in older age groups (p<0.001) from 12.6% (95% CI 5.8-19.4%; 11-20 years) to 9.7% (95% CI 5.7-13.6) among those older than 20. Risk factor analysis revealed young age, male sex, and number of people sharing a bed as factors associated with an increased risk for T. whipplei carriage. These results demonstrate that T. whipplei carriage is highly prevalent in this part of Africa. The high prevalence in early life and the analysis of risk factors suggest that transmission may peak during childhood facilitated through close person-to-person contacts., (© 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.)

Background: Haemolytic conditions may contribute to disease pathogenesis and severe clinical manifestations through the liberation of free haemoglobin (Hb) and production of toxic free haem. Thus, free Hb and haem should be associated with altered MetHb and COHb levels in malaria as in other conditions., Methods: This study comprises data collected at three different sites: (i) a retrospective analysis of the first arterial blood gas result (ABGS) of any patient during 2010 at the University Hospital in Lisbon; (ii) a retrospective analysis of ABGS from patients with severe malaria admitted to the intensive care unit in Berlin, Germany; and (iii) a prospective study of non-invasive MetHb measurements in children with and without malaria in Lambaréné, Gabon., Results: In Lisbon, the mean MetHb level was 1.4% (SD: 0.5) in a total of 17,834 ABGS. Only 11 of 98 samples with a MetHb level of >3.0 referred to infections. COHb levels showed no particular association with clinical conditions, including sepsis. In 13 patients with severe malaria in Berlin, the mean MetHb levels on admission was 1.29%, with 1.36% for cerebral malaria and 1.14% for non-cerebral malaria (P > 0.05). All COHb measurements were below 2.3%. In Lambaréné, Gabon, 132 healthy children had a mean MetHb level of 1.57%, as compared to 150 children with malaria, with a value of 1.77% and 2.05% in uncomplicated and complicated cases, respectively (P < 0.01)., Conclusions: The data appears consistent with the methaemoglobin/haem hypothesis in malaria and sepsis pathogenesis. However, although MetHb was significantly different between healthy controls and children with malaria in Africa, the difference was rather small, also when compared to previous studies. Still, non-invasive bedside MetHb testing may warrant further evaluation as it could be a simple adjuvant tool for prognosis in resource poor settings.

Staphylococcus aureus colonization is a risk factor for invasive disease. There is a need to understand S. aureus colonization in infancy as the burden of S. aureus infections in infants is high. We aimed to investigate the transmission of S. aureus between mothers and their newborns during the first year after delivery in an African setting. In a longitudinal cohort study, colonization of Gabonese mother-infant pairs was assessed at delivery and after 1, 9 and 12 months. Swabs were taken from mothers (nares, mammillae) and infants (nares and throat). Isolates were characterized and risk factors for colonization were assessed using a standardized questionnaire. We recruited 311 mothers and 318 infants including seven sets of twins. Maternal and infant colonization rates declined synchronously following a peak after 1 month at 40% (mothers) and 42% (infants). Maternal colonization was a risk factor for S. aureus carriage in infants. Based on spa typing, direct mother-to-infant transmission was evident in 5.6%. Of all methicillin-resistant isolates (n = 9), 44.4% were related to the USA300 clone; 56.7% (n = 261) of all S. aureus carried Panton-Valentine leukocidin encoding genes. Direct mother-to-infant transmission was rare and cannot explain the increase of carriage in infants within the first month. A transmission from external sources is likely and challenges the S. aureus infection control in newborns and infants in an African setting. The detection of USA300-related MRSA fuels the concern about the spread of this clone in Central Africa., (© 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.)

Children with sickle cell anaemia (SCA) might carry hospital-associated bacterial lineages due to frequent hospital stays and antibiotic treatments. In this study we compared Staphylococcus aureus from SCA patients (n=73) and healthy children (n=143) in a cross-sectional study in Gabon. S. aureus carriage did not differ between children with SCA (n=34, 46∙6%) and controls matched for age, residence and sex (n=67, 46∙9%). Both groups shared similar S. aureus genotypes. This finding points towards a transmission of S. aureus between both groups in the community. We conclude that resistance rates from population-based studies with healthy participants could therefore also be used to guide treatment and prophylaxis of endogenous infections in children with SCA despite a different selection pressure.

Little data is available on the epidemiology of Staphylococcus aureus in Africa. In the present study we aim at characterizing the population structure of S. aureus in healthy subjects from a rural and a semi-urban area in Lambaréné, Gabon as well as in hospital staff and inpatients. In total, 500 subjects were screened for S. aureus colonization of the nares, axillae and inguinal region. Overall, 146 (29%) were positive. We found 46 different spa types. The most frequent spa types were t084 (35%) and the agr II was the most prevalent subtype of the accessory gene regulator (56%, n=82). Five isolates (3%) were methicillin resistant S. aureus (MRSA). Carriage rates of S. aureus in Gabon are comparable to developed countries. MRSA is for the first time described and could pose a significant health threat in this region with limited access to microbiological laboratory facilities and to adequate antimicrobial agents., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Rapid and accurate diagnosis of malaria is central to clinical management and the prevention of drug-overuse, which may lead to resistance development, toxicity and economic losses. So far, light microscopy (LM) of Giemsa-stained thick blood smears is the gold standard. Under optimal conditions the procedure is fast and reliable; nevertheless a gain in speed would be a great advantage. Rapid diagnosis tests are an alternative, although they cost more and give qualitative instead of quantitative results. Light-emitting diode (LED) fluorescence microscopy (ledFM 400 ×, 1000 ×) may offer a reliable and cheap alternative, which can be used at the point of care., Methods: LedFM and conventional fluorescence microscopy (uvFM) were compared to LM in 210 samples from patients with history of fever in the last 24 hours admitted to the Albert Schweitzer Hospital in Lambaréné, Gabon., Results: Sensitivities were 99.1% for ledFM and 97.0% for uvFM, specificities 90.7% for ledFM 400 × and 92.6% for ledFM 1000 × and uvFM. High agreement was found in Bland-Altman-plot and Kappa coefficient (ledFM 1000 ×: 0.914, ledFM 400 × and uvFM: 0.895). The time to diagnosis for both FM methods was shorter compared to LM (LM: 43 min, uvFM: 16 min, ledFM 1000 ×: 14 min, ledFM 400 ×: 10 min)., Conclusion: ledFM is a reliable, accurate, fast and inexpensive tool for daily routine malaria diagnosis and may be used as a point of care diagnostic tool., (© 2011 Lenz et al; licensee BioMed Central Ltd.)

Background: Drug resistance contributes to the global malaria burden. Plasmodium falciparum dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) polymorphisms confer resistance to sulphadoxine-pyrimethamine (SP)., Methods: The study assessed the frequency of SP resistance-conferring polymorphisms in Plasmodium falciparum-positive samples from two clinical studies in Lambaréné. Their role on treatment responses and transmission potential was studied in an efficacy open-label clinical trial with a 28-day follow-up in 29 children under five with uncomplicated malaria., Results: SP was well tolerated by all subjects in vivo. Three subjects were excluded from per-protocol analysis. PCR-corrected, 12/26 (46%) achieved an adequate clinical and parasitological response, 13/26 (50%) were late parasitological failures, while 1/26 (4%) had an early treatment failure, resulting in early trial discontinuation. Of 106 isolates, 98 (92%) carried the triple mutant dhfr haplotype. Three point mutations were found in dhps in a variety of haplotypic configurations. The 437G + 540E double mutant allele was found for the first time in Gabon., Conclusions: There is a high prevalence of dhfr triple mutant with some dhps point mutations in Gabon, in line with treatment failures observed, and molecular markers of SP resistance should be closely monitored.

Unlabelled: The recombinant circumsporozoite protein (CS) based vaccine, RTS,S, confers protection against Plasmodium falciparum infection in controlled challenge trials and in field studies. The RTS,S recombinant antigen has been formulated with two adjuvant systems, AS01 and AS02, which have both been shown to induce strong specific antibody responses and CD4 T cell responses in adults. As infants and young children are particularly susceptible to malaria infection and constitute the main target population for a malaria vaccine, we have evaluated the induction of adaptive immune responses in young children living in malaria endemic regions following vaccination with RTS,S/AS01(E) and RTS,S/AS02(D). Our data show that a CS-specific memory B cell response is induced one month after the second and third vaccine dose and that CS-specific antibodies and memory B cells persist up to 12 months after the last vaccine injection. Both formulations also induced low but significant amounts of CS-specific IL-2(+) CD4(+) T cells one month after the second and third vaccine dose, upon short-term in vitro stimulation of whole blood cells with peptides covering the entire CS derived sequence in RTS,S. These results provide evidence that both RTS,S/AS01(E) and RTS,S/AS02(D) induced adaptive immune responses including antibodies, circulating memory B cells and CD4(+) T cells directed against P. falciparum CS protein., Trial Registration: ClinicalTrials.gov NCT00307021.

Objectives: To establish reference intervals for major haematological and biochemical parameters in Gabonese infants and children., Methods: The reference sample population consisted of 226 healthy infants (4-9 weeks of age) and 185 healthy children (18-60 months of age). Basic red cell parameters as well as total and differential white blood cell counts were performed. Clinical chemistry parameters consisted of glutamate-pyruvic transaminase and creatinine, and total bilirubin was measured in children. Statistical analysis was based on the guidelines of the Clinical and Laboratory Standards Institute. Nonparametric methods were used to determine 95% reference limits and their 90% confidence intervals., Results:   Compared to European populations, values for several red cell parameters (haemoglobin, haematocrit, red blood cell count, mean corpuscular volume) were lower and platelet counts were higher. Eosinophils were higher in the older age group, most likely caused by intestinal helminths., Conclusions: The study confirms the importance of establishing reference limits for local populations. The reference ranges could be used as a benchmark for similar populations in Central Africa., (© 2010 Blackwell Publishing Ltd.)

Different cytokines have been suggested to be involved in the pathogenesis of pulmonary tuberculosis (TB). The frequencies of Mycobacterium tuberculosis (MTB) specific CD4(+) and CD8(+) T cells, CD4(+)CD25(+) Forkhead Box Protein (FoxP)3(+) T cells, interleukin (IL)-6, interferon (IFN)-γ, Tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β and IL-10 were assessed in HIV-negative, pulmonary tuberculosis (TB) patients (n=30) and in healthy controls (n=23) in Gabon. Peripheral blood mononuclear cells (PBMC) were stimulated with purified protein derivative (PPD) and early secretory antigenic target-6 (ESAT-6). In patients, a pronounced pro-inflammatory cytokine response with highly significant increased levels of IL-6 and TNF-α accompanied by increased TGF-β was detectable. Differences in IFN-γ responses between patients and healthy individuals were less pronounced than expected. FoxP3 expression did not differ between groups. A distinct cytokine pattern is associated with active pulmonary TB in patients from Central Africa., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Background: The RTS,S/AS01(E) malaria candidate vaccine is being developed for immunization of African infants through the Expanded Program of Immunization (EPI)., Methods: This phase 2, randomized, open, controlled trial conducted in Ghana, Tanzania, and Gabon evaluated the safety and immunogenicity of RTS,S/AS01(E) when coadministered with EPI vaccines. Five hundred eleven infants were randomized to receive RTS,S/AS01(E) at 0, 1, and 2 months (in 3 doses with diphtheria, tetanus, and whole-cell pertussis conjugate [DTPw]; hepatitis B [HepB]; Haemophilus influenzae type b [Hib]; and oral polio vaccine [OPV]), RTS,S/AS01(E) at 0, 1, and 7 months (2 doses with DTPwHepB/Hib+OPV and 1 dose with measles and yellow fever), or EPI vaccines only., Results: The occurrences of serious adverse events were balanced across groups; none were vaccine-related. One child from the control group died. Mild to moderate fever and diaper dermatitis occurred more frequently in the RTS,S/AS01(E) coadministration groups. RTS,S/AS01(E) generated high anti-circumsporozoite protein and anti-hepatitis B surface antigen antibody levels. Regarding EPI vaccine responses upon coadministration when considering both immunization schedules, despite a tendency toward lower geometric mean titers to some EPI antigens, predefined noninferiority criteria were met for all EPI antigens except for polio 3 when EPI vaccines were given with RTS,S/AS01(E) at 0, 1, and 2 months. However, when antibody levels at screening were taken into account, the rates of response to polio 3 antigens were comparable between groups., Conclusion: RTS,S/AS01(E) integrated in the EPI showed a favorable safety and immunogenicity evaluation. Trial registration. ClinicalTrials.gov identifier: NCT00436007 . GlaxoSmithKline study ID number: 106369 (Malaria-050).

Summary Objectives: To evaluate the epidemiologic data of parasitic infections and co-infections in pregnant women in Lambaréné, Gabon., Methods: In Lambaréné, Gabon--a region of high endemicity for Plasmodium falciparum and helminths--we conducted a longitudinal survey of malaria and helminth infections during pregnancy., Results: Of 388 pregnant women included in the study, 98 (25%) experienced at least one episode of P. falciparum infection (incidence of 2.6 infections per year of pregnancy). One hundred and seventy pregnant women (49%) were infected with intestinal helminths, and 41 (12%) harboured Shistosoma haematobium. In total, 230 (65%) pregnant women carried at least one parasitic infection are 74 (22%) harboured at least two or more parasite species. Ascaris lumbricoides and primiparity were independently associated with Plasmodium infection during pregnancy [odds ratio (95% confidence intervals) 2.4, (1.4-3.8); 2.1, (1.3-3.5), respectively]., Conclusion: This study shows a high burden of parasitic infections with substantial degree of parasitic co-infections in pregnant women in a Central African region. This may have implications for immunological studies and operational research involving pregnant women., (© 2010 Blackwell Publishing Ltd.)

Malaria is still one of the major public health threats in sub-Saharan Africa. An effective vaccine could be a sustainable control measure that can be integrated into existing health infrastructures. The malaria vaccine candidate GMZ2 is a recombinant fusion protein of conserved parts of Plasmodium falciparum Glutamate Rich Protein and Merozoite Surface Protein 3 adjuvanted with aluminium hydroxide. GMZ2 is immunogenic and well tolerated in malaria-naive adults from Germany. To assess safety and immunogenicity in malaria-exposed individuals, 40 adults from Lambaréné, Gabon were randomly assigned to receive either 100 μg GMZ2 or a rabies control vaccine three times in monthly intervals. Both vaccines were well tolerated. One month after a full course of vaccination, GMZ2-vaccinated individuals had 1.4-fold (95% confidence interval: [1.1, 1.7]) higher baseline-corrected anti-GMZ2 antibody levels and more GMZ2-specific memory B-cells compared to the rabies group (p=0.039), despite a high prevalence of GMZ2-specific immune reactivity due to previous intense exposure to P. falciparum., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Built in 1981, the Medical Research Unit is located at the campus of the Albert Schweitzer Hospital. The main scientific activities of this research unit lie on clinical research focusing on antimalarial drugs and vaccines, and basic studies on pathogenesis of infectious diseases. Since 2002 the Medical Research Unit has experience in organising and hosting high quality training in clinical research in collaboration with the Vienna School of Clinical Research and other partners. For the future, this unit is involved as a key partner in the Central African Network on Tuberculosis, HIV/AIDS and Malaria (CANTAM) consortium playing a central role for the excellence in clinical research in Central Africa.

Information technology has become a key resource for research institutions, providing services such as hardware, software and network maintenance, as well as data management services. The IT department of the Medical Research Unit (MRU) of the Albert Schweitzer Hospital in Lambaréné, Gabon is a good example of how IT has developed at African Research Centres in recent years and demonstrates the scope of work that a modern research centre needs to offer. It illustrates the development in the past 15 years--from single computers maintained by investigators to the present situation of a group of well-trained local IT personal who are in charge of a variety of hardware and software and who also develop applications for use in a research environment. Open source applications are particularly suited for these needs and various applications are used in data management, data analysis, accounting, administration and quality management.

Background: Plasmodium falciparum malaria accounts for >1 million deaths annually, mostly among young children in sub-Saharan Africa. Identifying those individuals who are likely to die is crucial. Several factors have been independently associated with death. Because malaria is a systemic disease, a quantitative score combining such risk factors may be superior., Methods: We used both forward and backward stepwise logistic regression to select the best predictors of death, as evaluated for 23,890 African children with severe P. falciparum malaria. The study was conducted from December 2000 through May 2005 in 6 hospital-based research units (in Banjul in the Gambia, Blantyre in Malawi, Kilifi in Kenya, Kumasi in Ghana, and Lambaréné and Libreville in Gabon) in a network established to study severe malaria in African children (ie, the SMAC Network)., Results: The Lambaréné Organ Dysfunction Score (LODS) combines 3 variables: coma, prostration, and deep breathing. A LODS >0 (odd ratio, 9.6; 95% confidence interval, 8.0-11.4) has 85% sensitivity to predict death, and a LODS <3 is highly (98%) specific for survival., Conclusions: The LODS is a simple clinical predictor of fatal malaria in African children. This score provides accurate and rapid identification of children needing either referral or increased attention.

In the context of a trial studying intermittent preventive sulfadoxine-pyrimethamine treatment of malaria in infants in Lambaréné, Gabon, children aged 18-30 months were followed up after having received their last dose at an age of 15 months. In the intention-to-treat population, the protective efficacy against all malaria episodes was -18.0 (95% confidence interval, -97.4 to 29.5; P = .529). The protective efficacy against first or only anemia episode was -45.3 (95% confidence interval, -234.5 to 36.3; P=.375). The protective efficacies were negative and were not statistically significant. These results do not appear to support the concept of a rebound effect after intermittent preventive sulfadoxine-pyrimethamine treatment of malaria in infants. Clinical trials registration. NCT00167843.

Background: The malaria vaccine candidate antigen RTS,S includes parts of the pre-erythrocytic stage circumsporozoite protein fused to the Hepatitis B surface antigen. Two Adjuvant Systems are in development for this vaccine, an oil-in water emulsion--based formulation (AS02) and a formulation based on liposomes (AS01)., Methods & Principal Findings: In this Phase II, double-blind study (NCT00307021), 180 healthy Gabonese children aged 18 months to 4 years were randomized to receive either RTS,S/AS01(E) or RTS,S/AS02(D), on a 0-1-2 month vaccination schedule. The children were followed-up daily for six days after each vaccination and monthly for 14 months. Blood samples were collected at 4 time-points. Both vaccines were well tolerated. Safety parameters were distributed similarly between the two groups. Both vaccines elicited a strong specific immune response after Doses 2 and 3 with a ratio of anti-CS GMT titers (AS02(D)/AS01(E)) of 0.88 (95% CI: 0.68-1.15) post-Dose 3. After Doses 2 and 3 of experimental vaccines, anti-CS and anti-HBs antibody GMTs were higher in children who had been previously vaccinated with at least one dose of hepatitis B vaccine compared to those not previously vaccinated., Conclusions: RTS,S/AS01(E) proved similarly as well tolerated and immunogenic as RTS,S/AS02(D), completing an essential step in the age de-escalation process within the RTS,S clinical development plan., Trial Registration: ClinicalTrials.gov. NCT00307021.

The aim of this paper is to explore attitudes of mothers towards childhood vaccinations and reasons for non-attendance and non-adherence to mother-child clinics (MCCs). Forty in-depth interviews with mothers of children under 5 years of age revealed positive attitudes towards vaccination that seem at odds with the region's observed low vaccination coverage. Important reasons for MCC non-attendance included distance to the MCC, transport costs, negative experiences at MCCs (such as interactions with unfriendly staff) and mothers' feeling of shame provoked by different, often poverty-associated reasons such as attending the clinic with a dirty or poorly clothed child.

Plasmodium falciparum sequesters in the placenta. Cell-Dyn automated flow cytometric haematology analysers have the capacity to detect haemozoin-containing circulating leukocytes during routine FBC analysis. In Lambaréné, Gabon, 685 FBCs of pregnant women were analysed, yielding 86.8% sensitivity and 78.5% specificity compared to microscopy. In a subset of 37 Cell-Dyn positive but microscopy negative samples, PCR detected five positive cases. This methodology may serve as an adjunct rapid diagnostic tool for malaria during pregnancy, even in microscopically negative cases.

We evaluated the relationship between immune response markers and the multiplicity of Plasmodium falciparum infections in order to assess the validity of the latter as an indicator of the acquisition of anti-malarial immunity. Parasite populations present during malaria episodes of 64 Gabonese children who presented with at least 4 such attacks during active follow-up over a 7-year period were characterized using MSP-1 and MSP-2 PCR-based methods. Plasma samples taken at healthy and parasite-free phase were used to measure P. falciparum antigen-specific antibody and cytokine activity. We found evidence of intra- and inter-individual variation in the number of parasite genotypes present in different malaria episodes, although in 72% of isolates no more than 2 parasite genotypes were detectable. Samples with the highest multiplicity were from children with significantly lower (p < 0.03) antibody responses to specific asexual stage antigens. Additionally, the whole blood interferon-gamma production capacity was significantly higher (p < 0.02) in those with lower infection multiplicity. Malaria episodes with multiple clones indeed reflect a low level of acquired immunity and a consequently poor capacity to control the infection. These findings suggest that the multiplicity of falciparum infection may be a potentially useful parameter in the evaluation of malaria control interventions.

Objectives: To assess the proportion of children being stunted and underweight-for-age at 3, 9 and 15 months in Lambaréné, Gabon, using the WHO child growth standards released in 2006 as compared with the Centers for Disease Control and Prevention (CDC) 2000 and the National Center for Health Statistics (NCHS) 1978 child growth charts/references., Design and Setting: Prospective birth cohort in Lambaréné, Gabon., Subjects: Two hundred and eighty-nine children from birth to 15 months of age., Methods: Weight and length were recorded at 3, 9 and 15 months. Corresponding Z scores for stunting and underweight-for-age were calculated for the three different standards/references. Children with a height-for-age or weight-for-age below -2 SD of the corresponding reference median (Z score < or = -2) were classified as stunted or underweight-for-age, respectively., Results: With the new WHO 2006 standards a higher proportion (4.0%) of 3-month-old infants were underweight compared with the CDC (1.0%) or the NCHS (0.7%) child growth charts/references. In contrast to the NCHS references or the CDC charts, this proportion did not increase from 3 to 9 months or from 9 to 15 months. The proportion of children being stunted was highest (above 20%) with the WHO 2006 standards at all three ages. Again, in contrast to the old standards, this proportion did not increase from 3 to 9 months or from 9 to 15 months., Conclusions: The present results show considerably different growth faltering patterns for Gabonese children depending on the growth charts used to assess the prevalence of stunting and underweight. Shifting to the new WHO child growth standards may have important implications for child health programmes.

Community-acquired pneumonia (CAP) accounts for more than two million deaths per year in children < 5 years of age. Recognition of pathogens is vital for guiding antibiotic treatment. In Gabon, no epidemiologic data on childhood CAP were available to help guide antibiotic therapy. We conducted a prospective, hospital-based, cross-sectional survey at the Albert Schweitzer Hospital, Lambarene, Gabon, to assess the importance of atypical organisms (Chlamydia pneumoniae, Mycoplasma pneumoniae, Bordetella pertussis, and Legionella pneumophila) and Streptococcus pneumoniae in the etiology of CAP in children by means of real-time polymerase chain reaction, cell culture, and serology. Collectively, atypical bacteria accounted for 11% of cases with a special emphasis on B. pertussis, accounting for 6% of cases. Clinical differentiation of atypical from typical pneumonia in children remains challenging. Molecular diagnostic methods offer fast and highly sensitive diagnostic tools and would be able to help guide antimicrobial therapy in rural areas where follow-up is difficult.

Background: Diligent and correct laboratory diagnosis and up-front identification of risk factors for progression to severe disease are the basis for optimal management of malaria., Methods: Febrile children presenting to the Medical Research Unit at the Albert Schweitzer Hospital (HAS) in Lambaréné, Gabon, were assessed for malaria. Giemsa-stained thick films for qualitative and quantitative diagnosis and enumeration of malaria pigment, or haemozoin (Hz)-containing leukocytes (PCL) were performed, and full blood counts (FBC) were generated with a Cell Dyn 3000 instrument., Results: Compared to standard light microscopy of Giemsa-stained thick films, diagnosis by platelet count only, by malaria pigment-containing monocytes (PCM) only, or by pigment-containing granulocytes (PCN) only yielded sensitivities/specificities of 92%/93%; 96%/96%; and 85%/96%, respectively. The platelet count was significantly lower in children with malaria compared to those without (p < 0.001), and values showed little overlap between groups. Compared to microscopy, scatter flow cytometry as applied in the Cell-Dyn 3000(R) instrument detected significantly more patients with PCL (p < 0.01). Both PCM and PCN numbers were higher in severe versus non-severe malaria yet reached statistical significance only for PCN (p < 0.0001; PCM: p = 0.14). Of note was the presence of another, so far ill-defined pigment-containing group of phagocytic cells, identified by laser-flow cytometry as lymphocyte-like gated events, and predominantly found in children with malaria-associated anaemia., Conclusion: In the age group examined in the Lambaréné area, platelets are an excellent adjuvant tool to diagnose malaria. Pigment-containing leukocytes (PCL) are more readily detected by automated scatter flow cytometry than by microscopy. Automated Hz detection by an instrument as used here is a reliable diagnostic tool and correlates with disease severity. However, clinical usefulness as a prognostic tool is limited due to an overlap of PCL numbers recorded in severe versus non-severe malaria. However, this is possibly because of the instrument detection algorithm was not geared towards this task, and data lost during processing; and thus adjusting the instrument's algorithm may allow to establish a meaningful cut-off value.

Background: Antipyretic drugs are widely used in children with fever, though there is a controversy about the benefit of reducing fever in children with malaria. In order to assess the effect of ibuprofen on fever compared to placebo in children with uncomplicated Plasmodium falciparum malaria in Gabon, a randomized double blind placebo controlled trial, was designed., Methods: Fifty children between two and seven years of age with uncomplicated malaria were included in the study. For the treatment of fever, all patients "received" mechanical treatment when the temperature rose above 37.5 degrees C. In addition to the mechanical treatment, continuous fanning and cooling blanket, patients were assigned randomly to receive ibuprofen (7 mg/kg body weight, every eight hours) or placebo., Results: The fever clearance time using a fever threshold of 37.5 degrees C was similar in children receiving ibuprofen compared to those receiving placebo. The difference was also not statistically significant using a fever threshold of 37.8 degrees C or 38.0 degrees C. However, the fever time and the area under the fever curve were significantly smaller in the ibuprofen group compared to the placebo group., Conclusion: Ibuprofen is effective in reducing the time with fever. The effect on fever clearance is less obvious and depends on definition of the fever threshold., Trial Registration: The trial registration number is: NCT00167713.

Background: Insecticide-treated bed nets (ITNs) range among the most effective measures of malaria prophylaxis, yet their implementation level in sub-Saharan Africa is still low. The goal of this study was to investigate the influence of socio-economic factors on the use of bed nets by mothers in Gabon., Methods: A cross-sectional study was conducted completing pre-tested, interviewer-administered questionnaires exploring socioeconomic proxy measures with 397 mothers or guardians of young children. Respondents were grouped according to their socio-economic situation, using scores. The condition of the bed nets was evaluated during a home visit., Results: Socio-economic factors of wellbeing were negatively associated with bed net use, such as living in a stone house (OR 0.26, 95% CI 0.14-0.48), running water in the house (OR 0.44, 95% CI 0.21-0.92), shower/flush toilet in the house (OR 0.39/0.34, 95% CI 0.21-0.75/0.16-0.73), ownership of a freezer (OR 0.50, 95% CI 0.26-0.96) and belonging to the highest group in the economic score (OR 0.32, 95% CI 0.15-0.67). In contrast, similar factors were positively associated with a good maintenance condition of the bed nets: higher monthly income (OR 5.64, 95% CI 2.41-13.19) and belonging to the highest group in the economic score (OR 2.55, 95% CI 1.19 - 5.45)., Conclusion: Among the poorest families in Lambaréné the coverage with untreated nets (UTNs) is the highest, but the condition of these UTNs is the worst. To achieve a broad implementation of ITNs in Lambaréné, there is an urgent need for educational programmes as well as need-tailored marketing strategies for ITNs.

Background: Intermittent preventive treatment aims to maximize the protective effects of malaria chemoprophylaxis while minimizing the deleterious effects., Methods: In Gabon, 1189 infants received either sulfadoxine-pyrimethamine (SP; 250 and 12.5 mg, respectively) or placebo at 3, 9, and 15 months of age. Children were actively followed-up until 18 months of age., Results: In the intention-to-treat population at 18 months of follow-up, 84 children (17%) in the SP group had > or =1 episode of anemia, versus 108 (21%) in the placebo group (protective efficacy, 22% [95% confidence interval {CI}, -1% to 40%]; P=.06). In the intervention group, there were 66 episodes during 485 person-years at risk, compared with 79 episodes during 497 years in the placebo group (protective efficacy, 17% [95% CI, -24% to 45%; P=.36). The effects were similar at 12 months of follow-up. The study drug was safe and well tolerated., Conclusions: The intervention was efficacious, producing a reduction in risk for anemia but a smaller effect against malaria. It is a valuable additional tool to control malaria in a highly vulnerable age group. Remaining important questions are currently being addressed in further studies., Trial Registration: ClinicalTrials.gov identifier: NCT00167843.

There are rare comparative studies of the clinical and laboratory features of severe and moderate malaria, including predictors of poor outcome, in rural and urban areas for regions of high malaria transmission. We therefore studied 2,235 children hospitalized for malaria in a rural (Lambaréné) and an urban (Libreville) area in Gabon between January 2001 and December 2002. From children screened, 33% and 48% were hospitalized for malaria in Libreville and Lambaréné, respectively (P < 0.001). Two malaria clinical groups were identified according to the World Health Organization 2000 classification of severe malaria. In both areas, severe malaria was characterized by a high proportion of severe anemia. The case fatality rate was 5-fold lower in Lambaréné than in Libreville (1% versus 5%; P < 0.0001). In both sites, cerebral malaria associated with respiratory distress was the most important predictor of fatal malaria (odds ratio = 10.7, 95% confidence interval = 4.8-23.8 P < 0.0001).

We assessed the ability of ibuprofen to modulate tumor necrosis factor alpha (TNF-alpha), soluble tumor necrosis factor receptor type I (sTNFR-I), and soluble tumor necrosis factor receptor type II (sTNFR-II) responses during the treatment of fever in uncomplicated Plasmodium falciparum malaria, in a placebo-controlled, randomized, double-blind study of 50 pediatric patients in Lambaréné, Gabon. Treatment of the malaria involved the patients receiving intravenous quinine (12 mg/kg of quinine dihydrochloride every 12 h for 72 h) followed by a single dose of oral sulfadoxine/pyrimethamine (25 mg and 1.25 mg/kg). Fever was treated by mechanical treatment plus either ibuprofen (7 mg/kg every 8 h) or placebo during the hospitalization period. We determined serum concentrations of TNF-alpha, sTNFR-I, and sTNFR-II in peripheral blood throughout the treatment period in the two groups: ibuprofen and placebo groups. TNF-alpha levels were found to be positively correlated with body temperature. In contrast, TNF receptors levels did not differ between the two groups and the antipyretic effect of ibuprofen was not correlated with specific changes in sTNFR-I and sTNFR-II production. Our data suggest that TNF-alpha is involved in malarial fever, but soluble TNF receptors play no major role in fever modulation.