Until 2009, the Laverania subgenus counted only two representatives: Plasmodium falciparum and Plasmodium reichenowi. The recent development of non-invasive methods allowed re-exploration of plasmodial diversity in African apes. Although a large number of great ape populations have now been studied regarding Plasmodium infections in Africa, there are still vast areas of their distribution that remained unexplored. Gabon constitutes an important part of the range of western central African great ape subspecies (Pan troglodytes troglodytes and Gorilla gorilla gorilla), but has not been studied so far. In the present study, the diversity of Plasmodium species circulating in great apes in Gabon was analysed. The analysis of 1,261 faecal samples from 791 chimpanzees and 470 gorillas collected from 24 sites all over Gabon was performed. Plasmodium infections were characterized by amplification and sequencing of a portion of the Plasmodium cytochrome b gene. The analysis of the 1,261 samples revealed that at least six Plasmodium species circulate in great apes in Gabon (Plasmodium praefalciparum, Plasmodium gorA (syn Plasmodium adleri), Plasmodium gorB (syn Plasmodium blacklocki) in gorillas and Plasmodium gaboni, P. reichenowi and Plasmodium billcollinsi in chimpanzees). No new phylogenetic lineages were discovered. The average infection rate was 21.3% for gorillas and 15.4% for chimpanzees. A logistic regression showed that the probability of infection was significantly dependent on the freshness of the droppings but not of the host species or of the average pluviometry of the months of collection.

African great apes are naturally infected by a multitude of Plasmodium species most of them recently discovered, among which several are closely related to human malaria agents. However, it is still unknown whether these animals can serve as source of infections for humans living in their vicinity. To evaluate this possibility, we analysed the nature of Plasmodium infections from a bank of 4281 human blood samples collected in 210 villages of Gabon, Central Africa. Among them, 2255 were detected positive to Plasmodium using molecular methods (Plasmodium Cytochrome b amplification). A high throughput sequencing technology (454 GS-FLX Titanium technology, Roche) was then used to identify the Plasmodium species present within each positive sample. Overall, we identified with confidence only three species infecting humans in Gabon: P. falciparum, P. malariae and P. ovale. None of the species known to infect non-human primates in Central Africa was found. Our study shows that ape Plasmodium parasites of the subgenus Laverania do not constitute a frequent source of infection for humans. It also suggests that some strong host genetic barriers must exist to prevent the cross species transmission of ape Plasmodium in a context of ever increasing contacts between humans and wildlife.

The high frequency of bacterial infections represents a major threat to public health. In developing countries, they are still responsible for significant morbidity and mortality in pediatric populations with sickle cell disease, particularly in children under 5 years of age. Indeed, they have an increased susceptibility to bacterial infections due to their immune deficiency. This susceptibility is even greater for pneumococcal and salmonella infections. In addition, the underdevelopment of some countries and socio-economic factors increases this condition. This review examines the common and specific factors leading to infections in people with sickle cell disease in different types of developed and undeveloped countries. The threat of bacterial infections, particularly those caused by S. pneumoniae and Salmonella, is of increasing concern due to the rise in bacterial resistance to antibiotics. In light of this disturbing data, new strategies to control and prevent these infections are needed. Solutions could be systematic penicillin therapy, vaccinations, and probabilistic antibiotic therapy protocols.

African researchers continue to face numerous barriers that limit the global dissemination and advancement of their research. These include high open-access publication fees, requirements for publishing in high-impact journals, inability to attend or host international conferences, and limited access to published papers and resources. In this viewpoint, we focus on the specific challenge of attending […]

There have been many reports on the population genetic structure of Plasmodium falciparum from different endemic regions especially sub-Saharan Africa. However, few studies have been performed on neglected populations, such as the Pygmy populations. In this study, the population genetic structure of P. falciparum was investigated in the Baka Pygmies of Gabon and compared to that observed in neighboring villages composed mostly of Bantu farmers. A total of 342 blood samples were collected from 170 Baka Pygmies and 172 Bantus in the north of Gabon (Woleu Ntem Province). Plasmodium infections were characterized by sequencing a portion of the parasite cytochrome b gene. Population genetic structure of P. falciparum in the different villages was analysed using microsatellite markers and genes coding for antigenic proteins (MSP1, MSP2, GLURP, and EBA-175). Overall, prevalence of P. falciparum was around 57 % and no significant difference of prevalence was observed between Pygmies and Bantus. No significant differences of population genetic structure of P. falciparum was found between Pygmy and Bantu people except for one antigen-coding gene, glurp, for which genetic data suggested the existence of a potentially disruptive selection acting on this gene in the two types of populations. The genetic structure of P. falciparum followed a pattern of isolation by distance at the scale of the study. The prevalence and genetic diversity of P. falciparum observed in Baka demonstrates a significant transmission of the parasite in this population, and some exchanges of parasites with Bantu neighbours. Despite that, some antigen-coding genes seem to have had a particular evolutionary trajectory in certain Pygmy populations due to specific local human and/or mosquito characteristics.

Background: Sickle cell disease (SCD) is the world’s most common genetic blood disorder. Most infant deaths from SCD occur in sub-Saharan Africa, and the mortality rate is exceptionally high in Gabon in Central Africa. In Gabon, there are limited resources for early and accurate detection of sickle cell or trait conditions. Most affected individuals reside in low-resource areas where access to diagnostic testing is often very limited. The most commonly used diagnostic methods require trained staff, adequate infrastructure, electric power, and enough time to perform the analysis. These requirements do not currently allow mass screening to be performed in remote areas of Gabon. The purpose of this pilot study is to develop a standardized screening procedure for SCD in order to determine its prevalence in the southeast area of Gabon by using a rapid and reliable test that does not require significant resources, such as the Sickle SCAN® device. Methods: The accuracy of the Sickle SCAN® device was assessed based on testing 272 blood samples. The exact hemoglobin was identified in 100% of the samples. The test comprises three proprietary indicators that detect the presence of hemoglobin A, S, and C, thus allowing the user to rapidly distinguish between normal (HbAA, N=142), carrier (HbAS, N=41), and sickle cell disease (HbSS, N=88; HbSC, N=1) samples. Hemoglobin variants (S and C) were confirmed by capillary electrophoresis (MinicapR; Sebia). The sensitivity and specificity were calculated for each phenotype. Results: The Sickle SCAN® test analysis revealed the following normal and abnormal phenotypes, including sickle cell trait (HbAS=14,71%) and SCD [HbSS (32.35%) and HbSC (0,74)]. There are no false positives in Sickle SCAN® result for the presence of hemoglobin variant, compared to gold standard approaches to capillary electrophoresis. The estimated sensitivity of the Sickle Scan® test was 92.2%, 100%, and 100% for HbSS, HbAS, and HbSC, respectively. The specificity exceeded 88.23% for all phenotypes (HbSS, HbAS, and HbSC). Conclusion and Implications for Translation: The Sickle Scan® device was found to be reliable with a sensitivity of 92.2%, 100%, and 100% for HbSS, HbAS, and HbSC, respectively. The specificity exceeded 88% for all phenotypes. RESUME Contexte: La drépanocytose est la maladie génétique du sang la plus répandue dans le monde. La plupart des décès de nourrissons dus à la drépanocytose surviennent en Afrique subsaharienne, et le taux de mortalité est particulièrement élevé au Gabon, en Afrique Centrale. Au Gabon, les ressources pour la détection précoce et précise de l’anémie falciforme ou du trait de l’anémie sont limitées. La plupart des personnes touchées résident dans des zones à faibles ressources où l’accès aux tests de diagnostic est souvent très limité. Les méthodes de diagnostic les plus couramment utilisées nécessitent un personnel formé, une infrastructure adéquate, de l’électricité et suffisamment de temps pour effectuer l’analyse. Ces exigences ne permettent pas actuellement de réaliser un dépistage de masse dans les zones reculées du Gabon. L’objectif de cette étude pilote est de développer une procédure standardisée de dépistage de la drépanocytose afin de déterminer sa prévalence dans la région sud-est du Gabon en utilisant un test rapide et fiable qui ne nécessite pas de ressources importantes, tel que le dispositif Sickle SCAN®. Méthodes: La précision du dispositif Sickle SCAN® a été évaluée sur la base de 272 échantillons de sang. L’hémoglobine exacte a été identifiée dans 100% des échantillons. Le test comprend trois indicateurs exclusifs qui détectent la présence d’hémoglobine A, S et C, permettant ainsi à l’utilisateur de distinguer rapidement les échantillons normaux (HbAA, N=142), porteurs (HbAS, N=41) et drépanocytaires (HbSS, N=88; HbSC, N=1). Les variantes d’hémoglobine (S et C) ont été confirmées par électrophorèse capillaire (MinicapR; Sebia). La sensibilité et la spécificité ont été calculées pour chaque phénotype. Résultats: L’analyse du test Sickle SCAN® a révélé les phénotypes normaux et anormaux suivants, y compris le trait drépanocytaire (HbAS=14,71%) et l’anémie disséminée [HbSS (32,35%) et HbSC (0,74)]. Il n’y a pas de faux positifs dans le résultat de Sickle SCAN® pour la présence de variante d’hémoglobine, comparé aux approches de référence que sont l’électrophorèse capillaire. La sensibilité estimée du test Sickle Scan® était de 92,2%, 100% et 100% pour HbSS, HbAS et HbSC, respectivement. La spécificité était supérieure à 88,23 % pour tous les phénotypes (HbSS, HbAS et HbSC). Conclusion et Implications pour la Traduction: Le dispositif Sickle Scan® s’est avéré fiable avec une sensibilité de 92,2 %, 100 % et 100 % pour HbSS, HbAS et HbSC, respectivement. La spécificité était supérieure à 88 % pour tous les phénotypes. Copyright © 2022 Delicat-Loembet et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License CC BY 4.0.