Identification of termites from Gabon using MALDI-TOF MS.

Termites are one of the most common pests that damage wood and other cellulosic materials. Although Africa has more varieties of termite species than any other continent, few entomological studies have been conducted in Gabon. Identifying termites poses significant difficulties for entomologists. The aim of this study was to evaluate the reliability and confirm the significance of MALDI-TOF MS in identifying fresh termites collected in equatorial Africa. A total of 108 termites were collected from 13 termite nests during a field mission in 2021 in Lekedi and Bongoville, Gabon. Termites were morphologically identified and subjected to MALDI-TOF MS, then molecular analyses using the COI and 12S rRNA genes. Four termite species were morphologically identified in this study: Pseudacanthotermes militaris, Macrotermes muelleri, Macrotermes nobilis, and Noditermes indoensis. However, when using molecular biology, only three species were identified, namely Macrotermes bellicosus, P. militaris, and N. indoensis, because the specimens initially identified as M. muelleri and M. nobilis were found to be M. bellicosus. The MALDI-TOF MS spectral profiles of the termites were all of good quality, with intra-species reproducibility and inter-species specificity. The spectra of 98 termites were blind tested against our upgraded database, which included the spectra of ten termite specimens. All tested spectra were correctly matched to their respective species, with log score values (LSVs) ranging from 1.649 to 2.592. The mean LSV was 2.215 ± 0.203, and the median was 2.241. However, 95.91% (94/98) of our spectra had LSVs above 1.8. This study demonstrates how a proteomic approach can overcome termites' molecular and morphological identification limitations and serve as a useful taxonomic tool.

Carbapenem-producing Enterobacteriaceae in mothers and newborns in southeast Gabon, 2022.

Introduction: Infections caused by carbapenemase-producing Enterobacteriaceae (CPE) pose a significant threat, leading to severe morbidity and mortality among newborns. Methods: This study, conducted at Franceville hospital's maternity and neonatology wards from February 22nd to June 20th, 2022, investigated the prevalence of CPE in 197 parturients and 203 newborns. Rectal swabs were taken from parturients before delivery and from newborns 30 minutes after birth. Blood culture samples were collected if signs of infection were observed in newborns during a 28-day follow-up. A total of 152 environmental samples were obtained, comprising 18 from sinks, 14 from incubators, 27 from cradles, 39 from maternal beds, 14 from tables and desks, four from the two baby scales and 36 from bedside furniture. Results: None of the 203 newborns were found to be CPE carriers 30 minutes after delivery. CPE carriage was found in 4.6% of mothers. When comparing colonized and uncolonized parturients, well-established risk factors for CPE carriage, such as recent hospitalization and antibiotic therapy, were more frequently observed among CPE carriers (33.3 vs 10.6% for hospitalization in the past 15 days; 55.5 vs 30.3% for hospitalization during pregnancy, and 55.5 vs 35.1% for antibiotic therapy during pregnancy). Notably, the prevalence of treatment with amoxicillin and clavulanic acid was 44.4% in CPE carriers compared to 17.0% in non-carriers. The incidence density of CPE-associated bloodstream infection was 0.49 per 100 newborns, accounting for a fatal case of CPE-associated bacteremia identified in one of the 203 newborns. Seven environmental samples returned positive for CPE (5 sinks and two pieces of furniture). Whole genome sequencing, performed on the 25 CPE isolates, revealed isolates carrying blaNDM-7 (n=10), blaNDM-5 (n=3), blaOXA181 (n=10), blaOXA48 (n=2) or blaOXA244 (n=1), along with genetic traits associated with the ability to cause severe and difficult-to-treat infections in newborns. Core genome comparison revealed nine CPE belonging to three international high-risk clones: E. coli ST410 (four mothers and a sink), two E. coli ST167 (a mother and a piece of furniture), and K. pneumoniae ST307 (a sink and a piece of furniture), with highly similar genetic backgrounds shared by maternal and environmental isolates, suggesting maternal contamination originating from the environment. Discussion: Our study reveals key findings may guide the implementation of infection control measures to prevent nosocomial infections in newborns: the prevalence of CPE carriage in one out of 20 parturients, an infection occurring in one out of 400 newborns, substantial contamination of the care environment, clinical and environmental CPE isolates possessing genetic traits associated with the ability to cause severe and challenging infections, and clonal relationships between clinical and environmental isolates suggesting CPE spread within the wards, likely contributing to the acquisition and colonization of CPE by parturients during pregnancy.

Malaria Prevalence in Asymptomatic and Symptomatic Children Living in Rural, Semi-Urban and Urban Areas in Eastern Gabon.

BACKGROUND: Malaria remains a major public health issue in the world despite a decline in the disease burden. However, though symptomatic malaria is diagnosed and treated, asymptomatic infections remain poorly known and support transmission. This study assessed the prevalence of symptomatic and asymptomatic Plasmodium spp. infections in three areas in Gabon to monitor and evaluate the impact of malaria. METHODS AND RESULTS: A cross-sectional study was conducted in three areas of Gabon. Febrile and afebrile children aged 6 months to 15 years were included in this study. Malaria prevalence was determined by microscopy of and using rapid diagnostic test (RDT). Plasmodium spp. species were identified by PCR according to the Snounou method. The data were recorded in Excel, and the statistical analyses were performed using the software R version R 64 × 3.5.0. A total of 2381(333 asymptomatic and 107 symptomatic) children were included. The overall prevalence of malaria was 40% (952/2381), with the majority (77% symptomatic and 98% asymptomatic) of infections caused by Plasmodium falciparum. A high prevalence of malaria was found in infected children in rural and semi-rural areas. In these two areas, a higher prevalence of Plasmodium malariae was observed in asymptomatic. Furthermore, mixed infections were more prevalent in asymptomatic children than in symptomatic. CONCLUSION: This study showed that the prevalence of Plasmodium spp. infection varied according to the regions. The main species was Plasmodium falciparum, but in asymptomatic children the prevalence of Plasmodium malariae was high in rural areas. To help fight malaria more effectively asymptomatic infections should be taken into account and treated.

High prevalence of asymptomatic Anaplasma spp. infection in school-aged children in southeastern Gabon.

OBJECTIVES: The objective of this study was to evaluate the detection rates of asymptomatic Anaplasma spp. and Ehrlichia spp. infections in children in southeastern Gabon. METHODS: We conducted a cross-sectional study among school-aged children in southeastern Gabon between May and June 2021. Blood samples were collected. Anaplasmataceae, Anaplasma spp., and Ehrlichia spp. were detected by microscopy and polymerase chain reaction. RESULTS: Of the 452 blood samples collected, 57.5% (n/N=260/452) of the samples were positive for Anaplasma spp. and/or Ehrlichia spp. by microscopy, 86.9% (n/N=393/452) of the samples were positive for both Anaplasmataceae and Anaplasma spp., and none of the samples were found positive for Ehrlichia spp. PCR was more sensitive and specific than microscopy for detection of Anaplasma spp.. CONCLUSIONS: In our study, a significant number of positive blood samples for Anaplasma spp. were found in school-aged children in southeastern Gabon. Further studies are needed to determine the prevalence of different species of Anaplasma, their pathogenicity, and their transmission patterns.

A Sanger approach based on overlapping fragments to screen SARS-CoV-2 variants.

Since the beginning of the COVID-19 pandemic, the SARS-CoV-2 virus has undergone various genetic mutations which have led to the emergence of variants. The World Health Organization (WHO) defines Variants of Concern (VOCs) and Variants of Interest (VOIs) according to several criteria. These include significant changes in the transmissibility and pathogenicity of the virus characterized by mutations in the spike gene coding the spike glycoprotein. In this study, we designed ten Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR) assays in order to identify mutations of SARS-CoV-2 in overlapping fragments. Each assay contained mutations on the fragments sequenced by a Sanger method. The genomic analysis of the fragments allowed to identify the variant according to the position of the mutations. The assembly of the 10 fragments refined the analysis, highlighting all the mutations present in the S gene. Finally, a comparison of methods using a Next-Generation Sequencing (NGS) approches for samples enabled the method to be validated. By this method we have highlighted a characteristic mutation of the lineage B of SARS-CoV-2. We showed the circulation of SARS-CoV-2 belonging to lineage A and B in the beginning of the pandemic in Gabon. We have identified the Alpha, Delta and Omicron variants. This method would allow laboratories with limited financial means or without NGS instrument to obtain sequences of the S gene. This method wase very effective to highlight the circulation of variants, in particular VOCs and VOIs, in this developing country, Gabon, during the COVID-19 pandemic.

Detection of Plasmodium falciparum in Saliva and Stool Samples from Children Living in Franceville, a Highly Endemic Region of Gabon.

Due to the difficulty of obtaining blood samples, which is the invasive method that is currently used for the detection of Plasmodium spp., alternative diagnostic sampling methods that are effective and non-invasive are needed, particularly for long-term studies. Saliva and stool samples from malaria-infected individuals contain trace amounts of Plasmodium DNA and therefore could be used as alternatives. Malaria was screened using rapid diagnosis tests and confirmed via microscopy. Nested PCR tests targeting the Plasmodium falciparum-specific STEVOR gene were performed for blood, saliva and stool samples that were positive for malaria. Three hundred sixty-seven (367) children were enrolled and eighty (22.22%) were confirmed to be positive for malaria. Matched blood, saliva and stool samples were available for 35 children. By using blood smears as the gold standard for the diagnosis of malaria, our study indicates that Plasmodium DNA was more detectable in blood (100%) than in saliva (22.86%) and stools (14.29%). Applying qPCR to the STEVOR gene to detect Plasmodium falciparum DNA in saliva and stool samples cannot be considered as an alternative to the current malaria detection processes using blood specimens.

Evolution and spread of Plasmodium falciparum mutations associated with resistance to sulfadoxine-pyrimethamine in central Africa: a cross-sectional study.

BACKGROUND: Efficacy of sulfadoxine-pyrimethamine, the malaria chemoprophylaxis used in pregnant women, and in children when combined with amodiaquine, is threatened by the accumulation of mutations in the Plasmodium falciparum dihydropteroate synthase (pfdhps) and dihydrofolate reductase (pfdhfr) genes. Data on the prevalence of resistant alleles in central Africa and the new pfdhps I431V mutation, particularly associated with other mutations to form the pfdhps vagKgs allele, are scarce. We explored the frequency and geographical distribution of pfdhps and pfdhfr mutations in central Africa in 2014-18, and assessed the evolutionary origin of the vagKgs allele. METHODS: Samples were collected at 18 health-care centres in seven countries (Angola, Cameroon, Central African Republic, Democratic Republic of the Congo, Gabon, Nigeria, and Republic of the Congo) from patients who showed possible symptoms of malaria between March 1, 2014, and Oct 31, 2018. Samples that were positive for P falciparum were transported to a laboratory in Toulouse, France, and genotyped. The frequency of pfdhfr and pfdhps mutations was studied in 1749 samples. Microsatellites in pfdhps flanking regions and whole-genome analysis compared with parasite genomes from the data-sharing network MalariaGEN were performed on samples carrying the vagKgs allele. FINDINGS: Mapping of the prevalence of single nucleotide polymorphisms and corresponding alleles of pfdhfr and pfdhps showed a substantial spread of alleles associated with sulfadoxine-pyrimethamine resistance in central Africa during the 2014-18 period, especially an increase going west to east in pfdhps alleles carrying the K540E and A581G mutations. A high prevalence of the pfdhps I431V mutation was observed in Cameroon (exceeding 50% in the northern region) and Nigeria. Genomic analysis showed a recent African emergence and a clonal expansion of the most frequent pfdhps vagKgs allele. INTERPRETATION: Reduced sulfadoxine-pyrimethamine efficacy due to increased resistance is a worrying situation, especially because the malaria transmission level is high in central Africa. Although the resistance phenotype remains to be confirmed, the emergence and spread of the vagKgs allele in west and central Africa could challenge the use of sulfadoxine-pyrimethamine. FUNDING: Toulouse Institute for Infectious and Inflammatory Diseases.

Pentaclethra eetveldeana Leaves from Four Congo-Brazzaville Regions: Antioxidant Capacity, Anti-Inflammatory Activity and Proportional Accumulation of Phytochemicals.

Oxidative stress and inflammation play a key role in the occurrence of neurodegenerative diseases. Traditionally, Pentaclethra eetveldeana leaves are used in dementia treatment. Therefore, this study aimed to evaluate the antioxidant and anti-inflammatory activities as well as the phytochemical composition of Pentaclethra eetveldeana leaves from four Congo-Brazzaville regions. The 1.2-diphenyl-1-picrylhydrazyl radical-scavenging, ß-carotene bleaching and molybdenum reduction assays were used to assess the antioxidant activity. The protein denaturation and erythrocyte membrane stabilization tests were used to analyze the anti-inflammatory activity. Phytochemical screening, the quantification of polyphenols by spectrophotometry, as well as the determination of extraction yields were carried out. It was found that the extracts reduced molybdenum; furthermore, compared to ascorbic acid, they showed better antiradical activity and inhibited lipid peroxidation. Moreover, globally, the membrane-stabilizing power of the aqueous extracts was superior or comparable to diclofenac, while the same extracts were less effective for the inhibition of denaturation. All of the aqueous extracts contained polyphenols, saponins, alkaloids, anthraquinones, reducing sugar and cardiotonic glycosides. The total polyphenols, tannins and proanthocyanidins are produced proportionally from one region to another. Finally, the leaves from Brazzaville and Boundji contain flavonols, while those from Makoua and Owando contain flavones. Thus, Pentaclethra eetveldeana leaves contribute to traditional dementia treatment through their antioxidant and anti-inflammatory properties.

Knowledge, attitudes, and practices of mothers regarding childhood malaria in southeastern Gabon.

BACKGROUND: In Gabon, children under 5 years of age and pregnant women are the populations who are most at risk of malaria. Despite the presence of accessible health facilities, the community-based management of childhood fever remains a very common practice in Gabon, which may have serious consequences on child health. As such, the objective of this descriptive cross-sectional survey is to assess the mothers' perception and knowledge of malaria and its severity. METHODS: Different households were selected using the simple random sampling method. RESULTS: A total of 146 mothers from different households were interviewed in the city of Franceville, in southern Gabon. Among the households interviewed, 75.3% had a low monthly income (below the minimum monthly income of $272.73). Among the respondents, 98.6% of mothers had heard of malaria and 55.5% had heard of severe malaria. Regarding preventive measures, 83.6% of mothers used an insecticide-treated net as a means of protection. Self-medication was practiced by 68.5% of women (100/146). DISCUSSION: The use of health facilities was motivated by better care, the decision of the head of the family, but above all by the severity of the disease. Women identified fever as the main symptom of malaria, which could be beneficial for a quicker and more efficient management of the disease in children. Malaria educational campaigns should also increase awareness of severe forms of malaria and its manifestations. This study shows that Gabonese mothers react quickly when their children have fever. However, several external factors lead them to practice self-medication as a first resort. In this survey population, the practice of self-medication did not depend on social status, marital status, level of education, on the young age or inexperience of mothers (p > 0.05). CONCLUSIONS: The data revealed that mothers may underestimate severe malaria and delay medical care by self-medicating, which can have detrimental effects for children and hinder the regression of the disease.

Severe malaria in children and adolescents in Southeast Gabon.

INTRODUCTION: Malaria remains a significant public health problem in sub-Saharan Africa. Child mortality due to severe malaria remains high in developing countries despite improvements in malaria management and a better understanding of its pathophysiology. To address the lack of epidemiological studies on severe malaria in Gabon, this study describes the epidemiological aspects of severe malaria in rural, semi-rural, and urban areas of southeast Gabon. METHODS: Demographic, clinical, and laboratory data for children and adolescents aged 0-18 years were collected in 2019 from hospital records at three health facilities in southeastern Gabon. The patients included in the study were positive for P falciparum malaria diagnosed by microscopy with at least one of the malaria severity criteria. RESULTS: Severe malaria accounted for 18.8% (667/3552) of malaria cases. Children aged 0-5 years accounted for 71.8% (479/667) of all severe malaria cases. Adolescents over 15 years of age were the least affected by severe malaria with 4.2% (28/667). Across the study, severe anemia (49.0%, 327/667), convulsions (43.0%, 287/667), respiratory distress (5.1%, 34/667), and altered consciousness (4.8%, 32/667) were the most frequent clinical signs of severe malaria in children. Franceville was the locality most affected by severe malaria with 49.2% (328/667), followed by Koulamoutou with 42.0% (280/667) and Lastourville with 8.8% (59/667). Convulsions (50.6%, 166/328) and coma (6.1%, 20/328) were more frequent in children living in urban areas. In contrast, severe anemia (56.7%, 186/339) and jaundice (6.8%, 23/339) were more common in children living in semi-rural areas. CONCLUSION: Severe malaria is more prevalent in urban areas in regions with a high malaria transmission intensity. However, in this study, the epidemiological characteristics of severe malaria were similar in the three settings (urban, rural, and semi-rural areas) despite different levels of urbanization. Nevertheless, the various signs of severity were more frequent in Franceville, an urban area. Children under 5 years of age remain the most vulnerable age group.

Severe malaria in Gabon: epidemiological, clinical and laboratory features in Amissa Bongo Hospital of Franceville.

BACKGROUND: Malaria is the most deadly parasitic disease and continues to claim more than a half million of deaths across the world each year, mainly those of under-fives children in sub-Saharan Africa. The aim of this study was to determine the epidemiological, clinical and laboratory features of patients with severe malaria at the Centre Hospitalier Régional Amissa Bongo (CHRAB), a referral hospital in Franceville. METHODS: It was an observational descriptive study conducted at CHRAB over 10 months. All admitted patients at the emergency ward of all ages presenting with positive test to falciparum malaria diagnosed by microscopy and rapid test with clinical signs of severe illness describe by World Health Organization were enrolled. RESULTS: During this study, 1065 patients were tested positive for malaria, of them 220 had severe malaria. Three quarters (75.0%) were less than 5 years of age. The mean time to consultation was 3.5 ± 1 days. The most frequent signs of severity on admission were dominated by neurological disorders 92.27% (prostration 58.6% and convulsion 24.1%), followed by severe anemia 72.7%, hyperlactatemia 54.6%, jaundice 25% and respiratory distress 21.82%.The other forms such as hypoglycemia, haemoglobinuria, renal failure were found in low proportions < 10%. Twenty-one patients died, coma (aOR = 15.54, CI 5.43-44.41, p < 0.01), hypoglycemia (aOR = 15.37, CI 2.17-65.3, p < 0.01), respiratory distress (aOR = 3.85, CI 1.53-9.73, p = 0.004) and abnormal bleeding (aOR = 16.42, CI 3.57-104.73, p = 0.003) were identified as independent predictors of a fatal outcome. Anemia was associated with decreased mortality. CONCLUSION: Severe malaria remains a public health problem affecting mostly children under 5 years. Classification of malaria helps identify the most severely ill patients and aids early and appropriate management of the severe malaria cases.

Cytokine response in asymptomatic and symptomatic Plasmodium falciparum infections in children in a rural area of south-eastern Gabon.

Plasmodium falciparum is a parasite that causes asymptomatic or symptomatic malaria infections in humans depending on various factors. These infections are also a major cause of anemia in intertropical countries such as Gabon. Past studies have clearly demonstrated that inflammatory markers such as cytokines play a key role in the pathogenesis of malaria disease. However, the clinical manifestations of severe malaria vary according to the level of transmission and more information is needed to gain a better understanding of the factors involved. As such, the objective of this study was to investigate the circulating levels of nine cytokines in asymptomatic and symptomatic P. falciparum infections in Gabonese children and their roles in the pathogenesis of anemia. Blood samples were collected from 241 children aged 3 to 180 months in Lastourville, south-eastern Gabon. Diagnosis of P. falciparum infection was performed using Rapid Diagnosis Tests, microscopy and nested PCR. Levels in the plasma of the Th1 (IFN-γ, TNF-α, IL-6 and IL-12p70), Th17 (IL-17A and IL-22) and Th2 (IL-10, IL-4 and IL-13) cytokines were measured by ELISA. Data showed that IL-6, IFN-γ, IL-12p70, IL-10, and IL-13 levels were significantly higher in children with symptomatic P. falciparum infection compared to uninfected children. IL-10 levels were significantly higher in symptomatic children than in asymptomatic children, who had moderately increased levels compared to uninfected controls. Moreover, only IL-10 and IL-6 levels were significantly higher in children with severe malarial anemia compared to children with uncomplicated malaria who had significantly lower IL-10 levels than children with moderate malarial anemia. These data indicate that the progression of P. falciparum infection towards an advanced stage in children is accompanied by a significant increase in type Th1 and/or Th2 cytokines. These inflammatory mediators could serve as potential predictors of anemia for malaria patients.

Molecular Prevalence of Diarrheal Pathogens in Children with Acute Diarrhea in Southeastern Gabon.

Diarrheal diseases are a major cause of morbidity and mortality in infants and young children, particularly in sub-Saharan countries. In Gabon, there are few data on the prevalence of diarrheal pathogens in children. The aim of this study was to assess the prevalence of diarrheal pathogens in children with diarrhea in southeastern Gabon. Stool samples (n = 284) from Gabonese children 0 to 15 years of age with acute diarrhea were analyzed using polymerase chain reaction targeting 17 diarrheal pathogens. At least one pathogen was detected in 75.7% of samples (n = 215). Coinfection with multiple pathogens was observed in 44.7% of patients (n = 127). Diarrheagenic Escherichia coli was the most commonly detected pathogen (30.6%, n = 87), followed by adenovirus (26.4%, n = 75), rotavirus (16.9%, n = 48), Shigella sp. (16.5%, n = 47), Giardia duodenalis (14.4%, n = 41), norovirus GII (7.0%, n = 20), sapovirus (5.6%, n = 16), Salmonella enterica (4.9%, n = 14), astrovirus (4.6%, n = 13), Campylobacter jejuni/coli (4.6%, n = 13), bocavirus (2.8%, n = 8), and norovirus GI (2.8%, n = 8). Our study provides useful information on the possible causes of diarrheal diseases affecting children in southeastern Gabon. A similar study with a control group of healthy children is needed to assess the burden of the disease attributed to each pathogen.

Epidemiology of first cases of SARS-CoV-2 infection, from March to April 2020, in Gabon.

Background After the first cases of coronaviruses disease 2019 (COVID-19) in China in January 2020, we conducted an epidemiological surveillance of COVID-19 in Gabon. Methods We led molecular investigations on nasopharyngeal and oropharyngeal samples from the 1161 first suspected cases of COVID-19. We diagnosed the first case of COVID-19 on March, 12 2020. Results Among those suspected cases, 83 were confirmed cases. There was no significant difference in prevalence of SARS-CoV-2 between age groups (p=0.14). 73% were asymptomatic. The viral loads were significantly higher in the nasopharyngeal samples than in the oropharyngeal samples (p=0.03). There was no significant difference in viral loads between age groups (p=0.9895) and no correlation between clinical symptoms and viral loads (p=0.06042). A phylogenetic analysis performed with five sequences of the spike S gene showed that two sequences had the D614G mutation. Conclusion In conclusion, this study provides the first molecular data from Gabon concerning the COVID-19 pandemic. The data showed that most of the infected people were asymptomatic. The viral load was higher in the nasopharyngeal samples. The S gene analyzed suggested both introduction of the D614 and G614 variant in Gabon.

Epidémiology of malaria from 2019 to 2021 in the southeastern city of Franceville, Gabon.

BACKGROUND: In Gabon, a new national malaria control policy was implemented in 2003. It resulted in a decrease in the number of malaria cases in the country. In March 2020, the disruption of routine health services due to the COVID-19 pandemic has led to an increase in cases and deaths due to malaria. However, in Franceville, south-east Gabon, no data on malaria cases recorded before, during and after the COVID-19 epidemic has been published. Thus, the objective of this study was to determine the epidemiological characteristics of malaria in Franceville from 2019 to 2021. METHODS: A retrospectively study of malaria cases was performed at the Hôpital de l'Amitié Sino-Gabonaise (HASG). Information regarding age, gender, malaria diagnosis by microscopy and hematology cell count were collected from laboratory registers from June 2019 to December 2021. Malaria data were analyzed and correlated with seasonal variations. RESULTS: The data of 12,695 febrile patients were collected from the laboratory registers of the HASG, among which 4252 (33.5%) patients were found positive for malaria. The malaria prevalence was 37.5% in 2020 year. This prevalence was highest compared to the 2019 (29.6%) and 2021 (31.5%) year (p < 0.001). During the short rainy season (October to December), a large increase in malaria cases was observed all three year, from 2019 to 2021 (p > 0.05). CONCLUSION: The prevalence of malaria in Franceville was very high during COVID-19 pandemic. It is therefore necessary to strengthen existing interventions and implement more effective interventions.

Intermittent preventive treatment and malaria amongst pregnant women who give birth at the Centre Hospitalier Régional Paul Moukambi de Koula-Moutou in southeastern Gabon.

BACKGROUND: Evaluating malaria control strategies for pregnant women is essential. The objective of this study was to determine the factors influencing antenatal care (ANC) visit attendance, complete intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) and its impact on the health of pregnant women and their newborn babies living in semi-urban and rural areas of southeastern Gabon. METHODS: This transversal study was performed at the Centre Hospitalier Régional Paul Moukambi de Koula-Moutou (CHRPMK). Information regarding age, frequency of prenatal consultations, obstetric history, use of malaria control measures, use of IPTp-SP, malaria diagnostic of women and their newborns, were collected: (i): from birth registers from 1 January, 2018 to 31 December, 2019 and, (ii): a questionnaire from January to April 2020. RESULTS: In total, 1,851 and 323 pregnant women were included during the first and the second sub-set of study, respectively. In the first sub-set of data, the mean age was 26.18 ± 7.02 years and 96.54% (1,787/1,851) of pregnant women had attended ANC service but 54.45% had complete ANC visit attendance (at least 4 ANC). The complete ANC visit was linked with age (p < 0.001) and profession (p < 0.001). The complete IPTp-SP (at least 3 doses) was 58.87%. Complete IPTp-SP was linked to profession (aOR = 1.49, 95% CI [1.04-2.18], p < 0.001), ANC visit (aOR = 0.176, 95% CI [0.14-0.22], p < 0.034) and age (p = 0.03). Birth weight was higher for babies whose mothers had received complete IPTp-SP (p < 0,001) but the Apgar score was not influenced by the use of IPTp-SP (p = 0.71). In the second sub-set of data, the prevalence of plasmodial infection was 3.10% (95% IC [1.21-5]) and Plasmodium falciparum was responsible for 100% of infections. The prevalence of plasmodial infection was the same for all age groups (p = 0.69), gravidity (p = 0.13) and domestic control measures (p > 0.05). A low birth weight was statistically linked to the mother's plasmodial infection (p < 0.01). Furthermore, plasmodial infection was statistically linked to premature birth (p < 0.001). CONCLUSIONS: It was observed that attendance of women to ANC service and a complete IPTp-SP course is insufficient.

Malaria research in the Central African Republic from 1987 to 2020: an overview.

BACKGROUND: The national malaria control policy in the Central African Republic (CAR) promotes basic, clinical, and operational research on malaria in collaboration with national and international research institutions. Preparatory work for the elaboration of National Strategic Plans for the implementation of the national malaria control policy includes developing the research component, thus requiring an overview of national malaria research. Here, this survey aims to provide an inventory of malaria research as a baseline for guiding researchers and health authorities in choosing the future avenues of research. METHODS: Data sources and search strategy were defined to query the online Medline/PubMed database using the "medical subject headings" tool. Eligibility and study inclusion criteria were applied to the selected articles, which were classified based on year, research institute affiliations, and research topic. RESULTS: A total of 118 articles were retrieved and 51 articles were ultimately chosen for the bibliometric analysis. The number of publications on malaria has increased over time from 1987 to 2020. These articles were published in 32 different journals, the most represented being the Malaria Journal (13.73%) and the American Journal of Tropical Medicine and Hygiene (11.76%). The leading research topics were drug evaluation (52.94%), expatriate patients (23.54%), malaria in children (17.65%), morbidity (13.7%), and malaria during pregnancy (11.76%). The publications' authors were mainly affiliated with the Institut Pasteur of Bangui (41%), the French Military Medical Service (15.5%), and the University of Bangui (11.7%). Collaborations were mostly established with France, the UK, and the USA; some collaborations involved Switzerland, Austria, Pakistan, Japan, Sri Lanka, Benin, Cameroun, Ivory Coast, and Madagascar. The main sources of research funding were French agencies (28.6%) and international agencies (18.3%). Most studies included were not representative of the whole country. The CAR has the capacity to carry out research on malaria and to ensure the necessary collaborations. CONCLUSION: Malaria research activities in the CAR seem to reflect the priorities of national policy. One remaining challenge is to develop a more representative approach to better characterize malaria cases across the country. Finally, future research and control measures need to integrate the effect of COVID-19.

Cross-reactive immunity against SARS-CoV-2 N protein in Central and West Africa precedes the COVID-19 pandemic.

Early predictions forecasted large numbers of severe acute respiratory syndrome coronavirus (SARS-CoV-2) cases and associated deaths in Africa. To date, Africa has been relatively spared. Various hypotheses were postulated to explain the lower than anticipated impact on public health in Africa. However, the contribution of pre-existing immunity is yet to be investigated. In this study, the presence of antibodies against SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in pre-pandemic samples from Africa, Europe, South and North America was examined by ELISA. The protective efficacy of N specific antibodies isolated from Central African donors was tested by in vitro neutralization and in a mouse model of SARS-CoV-2 infection. Antibodies against SARS-CoV-2 S and N proteins were rare in all populations except in Gabon and Senegal where N specific antibodies were prevalent. However, these antibodies failed to neutralize the virus either in vitro or in vivo. Overall, this study indicates that cross-reactive immunity against SARS-CoV-2 N protein was present in Africa prior to the pandemic. However, this pre-existing humoral immunity does not impact viral fitness in rodents suggesting that other human immune defense mechanisms could be involved. In Africa, seroprevalence studies using the N protein are over-estimating SARS-CoV-2 circulation.

An adaptable platform for in-house hepatitis C serology.

Serology-based diagnosis remains one of the major tools for diagnosis and surveillance of infectious diseases. However, for many neglected diseases no or only few commercial assays are available and often with prices prohibiting large scale testing in low and middle-income countries (LMICs). We developed an adaptable enzyme-linked immunoassay (ELISA) using hepatitis C virus (HCV) as a proof-of-concept application. By combining the maltose-binding-protein with a multiepitope HCV protein, we were able to obtain a high concentration of protein suitable for downstream applications. Following optimization, the assay was verified using previously tested human samples from Canada, Denmark and Gabon in parallel with the use of a commercial protein. Sensitivity and specificity were calculated to 98 % and 97 % respectively, after accounting for non-specific binding and assay optimization. This study provides a thorough description of the development, and validation of a multiepitope ELISA-based diagnostic assay against HCV, which could be implemented at low cost. The described methodology can be readily adapted to develop novel ELISA-based diagnostic assays for other infectious pathogens with well-described immunogenic epitopes. This method could improve the diagnosis of neglected diseases for which affordable diagnostic assays are lacking.

Knowledge, Attitude and Practice during the COVID-19 Pandemic in South-East Gabon.

COVID-19 is an emerging respiratory disease; it was declared a global pandemic by the World Health Organization. This survey aimed to describe the knowledge, attitudes, perception and practices of the Gabonese public towards COVID-19. This study was performed on 1016 participants. All participants filled in the questionnaire voluntarily, reporting demographic characteristics and answering questions assessing their level of knowledge, attitudes, perceptions and practice towards COVID-19. Among participants, there were 535 men and 476 women. The mean age of the participants was 33.2 ± 16.7 years old. Almost all participants (98.1%) said that they had heard about COVID-19 but only 2.8% knew the pathogenic agent responsible for COVID-19. More than 80% knew that the disease could be transmitted by greeting infected people (87.3%), kissing an infected person (90.0%), touching an infected doorknob (83.5%) and attending meetings (83.9%). The mean knowledge score was higher among younger than older participants, higher among participants living in urban areas than those living in rural areas and higher among participants with higher levels of education than those with lower levels of education. In general, respondents had good knowledge of COVID-19 and a positive attitude towards using protective measures; however, there were differences according to gender, age group, place of residence, professional group and level of education.