Pregnant women living in areas of endemic fluorosis in Senegal and low birthweight newborns: case-control study

BackgroundIn developing countries, maternal and neonatal mortality is high. Among the causes of death during the neonatal period, low birth weight is crucial. A dose of fluoride beyond 2 mg/L causes enamel damage, possibly affecting the fetus. The aim of this study was to search for an association between dental fluorosis in the mother and low birthweight of the newborn.MethodologyThis was a case–control study performed in an endemic area in Senegal (Diourbel). It included 108 mothers who gave birth to newborns weighing less than 2500 g (cases) and 216 mothers with newborns weighing greater or equal to 2500 g (controls). Data on socio-demographic, lifestyle, history and pregnancy variables were collected. Those related to water consumption during pregnancy and dental fluorosis (Dean's index) were measured. The data were analyzed by R software. Logistic regression was used to identify associations and the statistical significance level was set to 0.05.ResultsThe proportions of mothers consuming well water were 62% among cases versus 43.5% among controls. The score 4 of Dean's Index was reported for 25.9% of cases versus 6.9% of controls. The water consumed and the modal score of Dean's Index were significantly associated with the occurrence of low birthweight adjusted for gender, consanguinity, anemia and hypertension.ConclusionLow birthweight was associated with pregnant women living in endemic areas. Defluoridation programs and access for pregnant women and children to high quality water are necessary in areas of endemic fluorosis.     

Vascular dysplasia in vascular surgery in an African area: 28 cases at the Dakar teaching hospital

This retrospective study was conducted to analyze the anatomic and clinical data concerning vascular dysplasia in vascular surgery patients seen in an African hospital and to assess its role in treatment. Twenty-eight patients (14 women and 14 men) were treated for vascular dysplasia between 1994 and 1998. There were 8 cases of hemangioma and 20 cases of vascular malformation. Average age of patients with hemangioma was 3.23 years, with a sex ratio of 0.33. There were 4 cases of mixed hemangioma, 3 of cutaneous hemangioma, and 1 of subcutaneous hemangioma. Cervicocephalic (n=4) and limb (n=3) localizations were the most frequent. Duplex Doppler did not reveal any signs of muscle disease. Four patients underwent surgery, for an early indication in 3 and a late indication in 1. Resection suture was performed in 3 cases and resection graft in one. Mean follow-up was 85.90 days. There was one case of early suppuration. There were no cases of recurrence or late complications and the operative wounds healed well. Vascular malformations concerned 20 patients (sex ratio 1.5, average age 15.55 years) with 16 cases of venous malformation including 4 patients with Klippel Trenaunay syndrome, three with arteriovenous malformation and one with capillary angioma. CT and arteriography were obtained in all cases. Limb localizations predominated (14 patients). In-depth extension was found in 6 cases of venous malformation. Sixteen patients underwent surgery for functional indications in 7. Resection suture was performed in 11 cases. Mean follow-up was 85.90 days. There were 4 early and 2 late postoperative complications. There has been no recurrence. Anatomic and clinical polymorphism of vascular dysplasia requires multidisciplinary collaboration in which vascular surgery plays an important role in complex or complicated forms of the disease in patients attending facilities with limited resources.     

Development and Characterization of PBSA-Based Green Composites in 3D-Printing by Fused Deposition Modelling

Fused deposition modelling is a rapidly growing additive manufacturing technology due to its ability to build functional parts with complex geometries. The mechanical properties of a built part depend on several process parameters. The effect of wood content on the properties of 3D printed parts has been studied. Four types of filaments using poly(butylene succinate-co-adipate) (PBSA) with different reinforcement levels of Typha stem powder 0%, 5%, 10%, and 15% by weight were used for 3D printing. The density of the filaments and parts printed in this study increased with the Typha stem powder content. The thermal stability, mechanical performance, and viscoelastic properties of the different biocomposite filaments and 3D printed objects were analysed. The results show an increase in the crystallisation kinetics and a slight decrease in the thermal stability of the biomaterials. Compared to virgin PBSA FDM filaments, the PBSA biocomposite filament filled with Typha stem powder showed an increase in the tensile strength of the parts and specimens from 2.5 MPa to 8 MPa and in the modulus of elasticity from 160 MPa to 375 MPa, respectively, with additions of 5%, 10%, and 15% by mass. The addition of Typha stem fibres generated an increase in the elastic behaviour and relaxation time of the biomaterial structure, visualised by increases in the values of the viscosity components. The surface morphology reveals a decrease in the porosity of the printed samples.     

Importation and Circulation of Vaccine-Derived Poliovirus Serotype 2, Senegal, 2020–2021

Environmental surveillance for poliovirus is increasingly used in poliovirus eradication efforts as a supplement to acute flaccid paralysis (AFP) surveillance. Environmental surveillance was officially established in 2017 in Senegal, where no poliovirus had been detected since 2010. We tested sewage samples from 2 sites in Dakar monthly for polioviruses. We identified a vaccine-derived poliovirus serotype 2 on January 19, 2021, from a sample collected on December 24, 2020; by December 31, 2021, we had detected 70 vaccine-derived poliovirus serotype 2 isolates circulating in 7 of 14 regions in Senegal. Sources included 18 AFP cases, 20 direct contacts, 17 contacts in the community, and 15 sewage samples. Phylogenetic analysis revealed the circulation of 2 clusters and provided evidence on the virus introduction from Guinea. Because novel oral polio vaccine serotype 2 was used for response activities throughout Senegal, we recommend expanding environmental surveillance into other regions.     

Pre-Pandemic Cross-Reactive Immunity against SARS-CoV-2 among Central and West African Populations

For more than two years after the emergence of COVID-19 (Coronavirus Disease-2019), significant regional differences in morbidity persist. These differences clearly show lower incidence rates in several regions of the African and Asian continents. The work reported here aimed to test the hypothesis of a pre-pandemic natural immunity acquired by some human populations in central and western Africa, which would, therefore, pose the hypothesis of an original antigenic sin with a virus antigenically close to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). To identify such pre-existing immunity, sera samples collected before the emergence of COVID-19 were tested to detect the presence of IgG reacting antibodies against SARS-CoV-2 proteins of major significance. Sera samples from French blood donors collected before the pandemic served as a control. The results showed a statistically significant difference of antibodies prevalence between the collected samples in Africa and the control samples collected in France. Given the novelty of our results, our next step consists in highlighting neutralizing antibodies to evaluate their potential for pre-pandemic protective acquired immunity against SARS-CoV-2. In conclusion, our results suggest that, in the investigated African sub-regions, the tested populations could have been potentially and partially pre-exposed, before the COVID-19 pandemic, to the antigens of a yet non-identified Coronaviruses.     

The azygos lobe: an unusual anatomical observation with pathological and surgical implications

The azygos lobe is a rare anomaly in broncho-pulmonary segmentation due to an unusual course of the azygos vein. Its radiological aspects are well known but there are few anatomical reports about its bronchial and vascular components. The authors describe the characteristic features in a particular case of the azygos lobe observed in the right lung after studying a fresh specimen and doing a casting of said specimen. This azygos lobe was in a position medial to the right upper lobe and above the hilum. It had the shape of an egg and was 5 cm high, 4 cm wide and 2 cm thick. The azygos fissure was of a vertical form. The lobe was ventilated by the posterior branch of the apical segmental bronchus (B1a). This latter was accompanied by two apical sub-segmental arteries (A1ai, A1aii) and the apical intersubsegmental vein (V1a). The new findings were that: first, the azygos lobe bronchus supplied a part of the right upper lobe; second, the passage of the azygos vein deformed the bronchus of the right upper lobe, and not that of the azygos lobe. This means that it was the right upper lobe, rather than the azygos lobe that was predisposed to the pathology. So, in excising this type of azygos lobe, particular precautions have to be taken to spare the bronchus of the azygos lobe that supplies the right upper lobe.     

Evidence for Multiple B- and T-Cell Epitopes in Plasmodium falciparum Liver-Stage Antigen 3

Liver-stage antigen 3 (LSA-3) is a new vaccine candidate that can induce protection against Plasmodium falciparum sporozoite challenge. Using a series of long synthetic peptides (LSP) encompassing most of the 210-kDa LSA-3 protein, a study of the antigenicity of this protein was carried out in 203 inhabitants from the villages of Dielmo (n = 143) and Ndiop (n = 60) in Senegal (the level of malaria transmission differs in these two villages). Lymphocyte responses to each individual LSA-3 peptide were recorded, some at high prevalences (up to 43%). Antibodies were also detected to each of the 20 peptides, many at high prevalence (up to 84% of responders), and were directed to both nonrepeat and repeat regions. Immune responses to LSA-3 were detectable even in individuals of less than 5 years of age and increased with age and hence exposure to malaria, although they were not directly related to the level of malaria transmission. Thus, several valuable T- and B-cell epitopes were characterized all along the LSA-3 protein, supporting the antigenicity of this P. falciparum vaccine candidate. Finally, antibodies specific for peptide LSP10 located in a nonrepeat region of LSA-3 were found significantly associated with a lower risk of malaria attack over 1 year of daily clinical follow-up in children between the ages of 7 and 15 years, but not in older individuals.Preerythrocytic malaria antigens are critical targets of protective immune responses induced by irradiated sporozoites in humans (9, 22). The demonstration of T-cell-mediated protection in mice immunized by this means (10, 16), the acquisition of a significant level of protection against homologous Plasmodium falciparum challenge in human volunteers (22), and the induction by liver-stage antigens of a high level of protection against P. falciparum infection in chimpanzees (19, 31) all point to a major role for preerythrocytic stage antigens as vaccine candidates.Liver-stage antigen 3 (LSA-3) is a novel antigen expressed at the preerythrocytic stages (4). LSA-3 was selected by the differential immune response found between protected and nonprotected volunteers, both similarly immunized with irradiated sporozoites (4, 9). The gene encoding LSA-3 is unusually well-conserved (4), in contrast with many other malaria vaccine candidates (11, 19, 23). More than 10 dominant T-helper (Th), cytotoxic T-lymphocyte, and B-cell epitopes have already been characterized in LSA-3 (20), some of them displaying cross-reactivity with an homologous antigen in Plasmodium yoelii (2). The protective potential of LSA-3 was demonstrated by a series of experiments in chimpanzees and Aotus monkeys challenged with P. falciparum (4, 21) and in mice challenged by P. yoelii following immunization either by recombinant proteins with adjuvant or by formulations without adjuvant, such as recombinant proteins adsorbed on microparticles or lipopeptides in phosphate-buffered saline (PBS) (4), or DNA-based immunization (29). These convergent results stress the potential of LSA-3 as a prime vaccine candidate.We therefore decided to further analyze the antigenicity of LSA-3 and to investigate immune responses to discrete regions of the protein in exposed individuals living in areas where malaria is endemic.T- and B-cell responses were evaluated in subjects living in two villages in Senegal, West Africa, where malaria is endemic, using three small synthetic peptides and a series of 17 overlapping long synthetic peptides (LSP) encompassing most of the LSA-3 protein. In keeping with preliminary results (20), we found a high prevalence of responses to most regions of this preerythrocytic stage antigen in individuals of different age groups. These results bring additional arguments in favor of the potential of the LSA-3 protein for vaccine development.