Roméo Karl Imboumy-Limoukou

Background: Urogenital schistosomiasis is endemic in Gabon. Our study aimed to detect the prevalence of urinary schistosomiasis and to evaluate the diagnostic performance of the qPCR technique compared to microscopy for the detection of Schistosoma haematobium at the community level in a semi-rural area. Method: A cross-sectional survey was carried out. Urine samples were examined using Urine TICK test strips, a filtration technique, and qPCR. Schistosoma haematobium was detected by targeting the Dra1 gene. Results: The prevalence of urogenital schistosomiasis was determined and the performance of real-time PCR and urine strips was compared with that of urinary filtration. A total of 281 participants were enrolled in the study. The prevalence of urogenital schistosomiasis was increased slightly with the molecular technique (40.9%) compared to microscopy (36.7%), and the hematuria rate with Urine STICK was 33.5%. SAC (5–14 years old), Pre-SAC (>5 years old), and adolescents (15–17 years old) were the most affected group according to, respectively, whatever method was used. qPCR showed good agreement with microscopy, as well as excellent sensitivity (99.03%) and specificity (93.3). There was a good correlation between the number of eggs per 10 mL and the cycle threshold range. Conclusion: These results show the importance of using a combination of diagnostic tools in the surveillance of schistosomiasis, particularly in preschool children, adolescents, women of childbearing age, and chronic and asymptomatic cases.

Background: Malaria remains the deadliest parasitic disease and continues to cause more than half a million deaths across the world each year, mainly victims are sub-Saharan children. Malaria is a common reason for paediatric hospitalisation. Objective: The objective was to characterise malaria and describe the evolution after treatment in the paediatric department of the University Hospital Centre Amissa Bongo de Franceville. Methods: This was a cross-sectional study conducted from 1 February 2023 to 15 May 2023. A clinical and biological diagnosis was made in febrile children aged from 6 months to 15 years. Results: A total of 306 patients were included. The mean age was 50.4 ± 44.3 months, 94.3% had consulted within ≥48 h and self-medication was practiced by 83.3%. The prevalence of malaria was 17.3%. Fever ˃39°8C (adjusted odds ratios [aOR] = 2.68; 95% confidence interval [CI] = [1.32–5.48]; P < 0.01), chills (aOR = 2.14; 95% CI = [1.13–4.11]; P < 0.01) and nausea–vomiting (aOR = 2.03; 95% CI = [1.06–3.83]; P = 0.03) were the factors associated with the occurrence of malaria. The majority of children were treated for simple malaria with artemisinin-based combination therapy. A total of 16/53 was seen in post-therapeutic consultation. Of them, 2 patients had a positive thick drop. Conclusion: Non-compliance with preventive measures and the misuse of antimalarials further complicate the clinical picture, requiring parenteral management for the most part.

A better understanding of malaria epidemiology in both asymptomatic and symptomatic individuals is essential for developing strategies to control the disease. This study was conducted to determine Plasmodium infection prevalence and its associated factors among people living in Franceville (urban area) and in the villages of Pana and Mvengue (rural areas) in south‐east Gabon between April and July 2022. This cross‐sectional study was conducted among all consenting residents of Franceville, Mvengue, and Pana between April and July 2022. After obtaining informed consent, Plasmodium sp. infection was screened by microscopy, and a structured questionnaire was developed to record sociodemographic data, attitudes, and practices regarding malaria. A total of 976 participants were included, with 491 in urban areas and 485 in rural areas. The overall prevalence of Plasmodium sp. infection was 21.62% (211/976; 95% confidence interval (CI) [19.15–24.31]). The prevalence was highest in children aged 6–11 years. In urban areas, the prevalence was 19.35% (95/491; 95% CI [16.10–23.07]), and 96.84% of infections were asymptomatic. The most infected age group was 18–23 years. In rural areas, the prevalence was 23.92% (116/485, 95% CI [20.34–27.91], and 93.97% (109/116) of infections were asymptomatic. Socioeconomic characteristics, attitudes, and practices towards Plasmodium sp. infection were not associated with a risk of asymptomatic malaria infection. This study highlights the importance of asymptomatic Plasmodium sp. infection in south‐east Gabon and the need for control strategies adapted to different areas and age groups. Detection and treatment of asymptomatic carriers could be an important lever for malaria control and elimination in the country.

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.

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, β-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.

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.

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. Method It was an observational descriptive study conducted at CHRAB over ten months. All admitted patients at the emergency ward of all ages presenting with positive test to falciparum malaria diagnose 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 younger than 5 years. 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% in particular 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 Conclusion Severe malaria remains a public health problem affecting mostly children under five years. Classification of malaria helps identify the most severely ill patients and aids early and appropriate management of the severe malaria cases.

BackgroundCOVID-19 is an emerging respiratory disease caused by severe acute respiratory syndrome coronavirus SARS-CoV-2. It has spread from China to more than 200 countries and has been declared a global pandemic by the World Health Organization (WHO). This survey aimed to describe the knowledge, attitudes, perception and practices (KAP) of the Gabonese public towards the COVID-19 disease.MethodsThis cross-sectional study was performed on 1016 participants aged 10 years and over in rural and urban area in south-east Gabon, using a questionnaire. All participants filled the questionnaire voluntarily, reporting demographic characteristics and answering questions assessing their level of knowledge, attitudes, perceptions and practice toward the COVID-19. ResultsAmong the 1016 participants, there were 535 men (52.7%) and 476 women (46.9%). 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. Only 20.9% of respondents thought that vaccination can protect them but 51.9% were looking forward to getting the vaccine when available. 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 doorknobs (83.5%), and attending meetings (83.9%). The mean knowledge score was higher among younger than older participants, higher among participants living in urban area than those living in rural areas, and higher among participants with higher levels of education than those with lower levels of education.ConclusionIn general, respondents had good knowledge of COVID-19, and a positive attitude towards using protective measures. These results are encouraging in the fight against the spread of COVID-19 in Gabon. However, efforts are needed to improve the knowledge level in older participants, those living in rural areas and those with low levels of education. Awareness campaigns in local languages could, for example, be conducted to improve knowledge of the disease in rural areas.

Background: Pediculus humanus, which includes two ecotypes (body and head lice), is an obligate bloodsucking parasite that co-evolved with their human hosts over thousands of years, thus providing a valuable source of information to reconstruct the human migration. Pediculosis due to head lice occurred each year throughout the world and several pathogenic bacteria, which are usually associated with body lice, are increasingly detected in them. In Gabon, where this pediculosis is still widespread, there is a lack of data on genetic diversity of head lice and their associated bacteria. Methods: This study aimed to investigate the phylogeny of head lice collected in Gabon and their associated bacteria, using molecular tools. Between 26 March and 11 April 2018, 691 head lice were collected from 86 women in Franceville. We studied the genetic diversity of these lice based on the cytochrome b gene, then we screened them for DNA of Bartonella quintana, Borrelia spp., Acinetobacter spp., Yersinia pestis, Rickettsia spp., R. prowazekii, Anaplasma spp. and C. burnetii, using real time or standard PCR and sequencing. Results: Overall 74.6% of studied lice belonged to Clade A, 25.3% to Clade C and 0.1% to Clade E. The phylogenetic analysis of 344 head lice yielded 45 variable positions defining 13 different haplotypes from which 8 were novel. Bacterial screening revealed the presence of Borrelia spp. DNA in 3 (0.4%) of 691 head lice belonging to Clade A and infesting one individual. This Borrelia is close to B. theileri (GenBank: MN621894). Acinetobacter spp. DNA has been detected in 39 (25%) of the 156 screened lice; of these 13 (8.3%) corresponded to A. baumannii. Acinetobacter nosocomialis (n = 2) and A. pittii (n = 1) were also recorded. Conclusions: To of our knowledge, this study is the first to investigate the genetic diversity of head lice from Gabon. It appears that Clade C is the second most important clade in Gabon, after Clade A which is known to have a global distribution. The detection of Borrelia spp. DNA in these lice highlight the potential circulation of these bacteria in Gabon.

Measles is one of the most infectious diseases with a high mortality rate worldwide. It is caused by the measles virus (MeV) which is a single stranded RNA virus with genetic diversity based on the nucleoprotein gene, including 24 genotypes. In Gabon, several outbreaks occurred in the past few years, especially in 2016 in Libreville and Oyem. A surveillance network of infectious diseases highlighted a measles outbreak which occurred in the south of Gabon from April to June 2017. Clinical specimens of urine, blood, throat and nasal swabs were collected in the two main cities of the Haut-Ogooue province, Franceville and Moanda. Virological investigations based on real-time polymerase chain reaction for molecular diagnosis and conventional PCR for genotype identification were done. Specimens were collected from 139 suspected measles patients. A total of 46 (33.1%) children and adults were laboratory-confirmed cases among which 16 (34.8%) were unvaccinated, 16 (34.8%) had received one dose, and 11 (23.9%) had received two doses of the measles vaccine. Phylogenetic analysis revealed that all the sequences of the nucleoprotein gene belonged to genotype B3. Measles infection was more commonly confirmed among those with one recorded dose compared to suspect cases with none, unknown or two recorded doses. The molecular characterization of the strains showed the circulation of the B3 genotype which is endemic on the African continent, thirty years after the B2 genotype was described in an outbreak in Libreville, the capital of Gabon. These findings highlight that surveillance and molecular investigation of measles should be continued in Gabon.