Regulatory T Cells in Human Lymphatic Filariasis: Stronger Functional Activity in Microfilaremics

Infection with filarial parasites is associated with T cell hyporesponsiveness, which is thought to be partly mediated by their ability to induce regulatory T cells (Tregs) during human infections. This study investigates the functional capacity of Tregs from different groups of filarial patients to suppress filaria-specific immune responses during human filariasis. Microfilaremic (MF), chronic pathology (CP) and uninfected endemic normal (EN) individuals were selected in an area endemic for Brugia timori in Flores island, Indonesia. PBMC were isolated, CD4CD25hi cells were magnetically depleted and in vitro cytokine production and proliferation in response to B. malayi adult worm antigen (BmA) were determined in total and Treg-depleted PBMC. In MF subjects BmA-specific T and B lymphocyte proliferation as well as IFN-gamma, IL-13 and IL-17 responses were lower compared to EN and CP groups. Depletion of Tregs restored T cell as well as B cell proliferation in MF-positives, while proliferative responses in the other groups were not enhanced. BmA-induced IL-13 production was increased after Treg removal in MF-positives only. Thus, filaria-associated Tregs were demonstrated to be functional in suppressing proliferation and possibly Th2 cytokine responses to BmA. These suppressive effects were only observed in the MF group and not in EN or CP. These findings may be important when considering strategies for filarial treatment and the targeted prevention of filaria-induced lymphedema

Mycorrhizal Symbiosis for Sustainable Optimization of Tropical Agriculture: A Review of Research

Excessive application of chemical fertilizers and other agrochemicals can cause significant imbalances in soils and agricultural ecosystems. To minimize these impacts, biofertilizers and organic fertilizers are needed to maintain a sustainable production system. The use of subterranean microorganisms in agriculture to stimulate plant growth and improve yields has recently received increasing interest. In this context, mycorrhizae represent a viable solution to mitigate these adverse effects. Mycorrhizal fungi are able to form a symbiotic relationship with the roots of plants in the environment. Mycorrhizal fungus helps the plant to absorb nutrients and water. In addition, mycorrhizal fungi play a crucial role in storing carbon (C) in the soil. Most previous studies have just considered the effects of AMF species on a specific crop in one particular area but have not assessed the balance of AMF in production systems in tropical agriculture. This consideration should allow for the optimization of cropping practices through a review of the work on the use of AMF in tropical agriculture production systems. In this paper, we will discuss, through different examples of experiments carried out in the tropics, the performance of different strategies for managing the potential of AMF to maintain a sustainable production system

A “reverse pharmacology” approach for developing an anti-malarial phytomedicine

A “reverse pharmacology” approach to developing an anti-malarial phytomedicine was designed and implemented in Mali, resulting in a new standardized herbal anti-malarial after six years of research. The first step was to select a remedy for development, through a retrospective treatment-outcome study. The second step was a dose-escalating clinical trial that showed a dose-response phenomenon and helped select the safest and most efficacious dose. The third step was a randomized controlled trial to compare the phytomedicine to the standard first-line treatment. The last step was to identify active compounds which can be used as markers for standardization and quality control. This example of “reverse pharmacology” shows that a standardized phytomedicine can be developed faster and more cheaply than conventional drugs. Even if both approaches are not fully comparable, their efficiency in terms of public health and their complementarity should be thoroughly considered

Multivariable regression analysis in Schistosoma mansoni-infected individuals in the Sudan reveals unique immunoepidemiological profiles in uninfected, egg+ and non-egg+ infected individuals

Background: In the Sudan, Schistosoma mansoni infections are a major cause of morbidity in schoolaged children and infection rates are associated with available clean water sources. During infection, immune responses pass through a Th1 followed by Th2 and Treg phases and patterns can relate to different stages of infection or immunity. Methodology: This retrospective study evaluated immunoepidemiological aspects in 234 individuals(range 4–85 years old) from Kassala and Khartoum states in 2011. Systemic immune profiles(cytokines and immunoglobulins) and epidemiological parameters were surveyed in n = 110 persons presenting patent S. mansoni infections (egg+), n = 63 individuals positive for S. mansoni via PCR in sera but egg negative (SmPCR+) and n = 61 people who were infection-free (Sm uninf). Immunoepidemiological findings were further investigated using two binary multivariable regression analysis. Principal Findings: Nearly all egg+ individuals had no access to latrines and over 90% obtained water via the canal stemming from the Atbara River. With regards to age, infection and an egg+ status was linked to young and adolescent groups. In terms of immunology, S. mansoni infection per se was strongly associated with increased SEA-specific IgG4 but not IgE levels. IL-6, IL-13 and IL-10 were significantly elevated in patently-infected individuals and positively correlated with egg load. In contrast, IL-2 and IL-1β were significantly lower in SmPCR+ individuals when compared to Sm uninf and egg+ groups which was further confirmed during multivariate regression analysis. Conclusions/Significance: Schistosomiasis remains an important public health problem in the Sudan with a high number of patent individuals. In addition, SmPCR diagnostics revealed another cohort of infected individuals with a unique immunological profile and provides an avenue for future studies on non-patent infection states. Future studies should investigate the downstream signalling pathways/mechanisms of IL-2 and IL-1β as potential diagnostic markers in order to distinguish patent from non-patent individuals

Brugia malayi Microfilariae Induce a Regulatory Monocyte/Macrophage Phenotype That Suppresses Innate and Adaptive Immune Responses

Background Monocytes and macrophages contribute to the dysfunction of immune responses in human filariasis. During patent infection monocytes encounter microfilariae in the blood, an event that occurs in asymptomatically infected filariasis patients that are immunologically hyporeactive. Aim To determine whether blood microfilariae directly act on blood monocytes and in vitro generated macrophages to induce a regulatory phenotype that interferes with innate and adaptive responses. Methodology and principal findings Monocytes and in vitro generated macrophages from filaria non-endemic normal donors were stimulated in vitro with Brugia malayi microfilarial (Mf) lysate. We could show that monocytes stimulated with Mf lysate develop a defined regulatory phenotype, characterised by expression of the immunoregulatory markers IL-10 and PD-L1. Significantly, this regulatory phenotype was recapitulated in monocytes from Wuchereria bancrofti asymptomatically infected patients but not patients with pathology or endemic normals. Monocytes from non-endemic donors stimulated with Mf lysate directly inhibited CD4+ T cell proliferation and cytokine production (IFN-γ, IL-13 and IL-10). IFN-γ responses were restored by neutralising IL-10 or PD-1. Furthermore, macrophages stimulated with Mf lysate expressed high levels of IL-10 and had suppressed phagocytic abilities. Finally Mf lysate applied during the differentiation of macrophages in vitro interfered with macrophage abilities to respond to subsequent LPS stimulation in a selective manner. Conclusions and significance Conclusively, our study demonstrates that Mf lysate stimulation of monocytes from healthy donors in vitro induces a regulatory phenotype, characterized by expression of PD-L1 and IL-10. This phenotype is directly reflected in monocytes from filarial patients with asymptomatic infection but not patients with pathology or endemic normals. We suggest that suppression of T cell functions typically seen in lymphatic filariasis is caused by microfilaria-modulated monocytes in an IL-10-dependent manner. Together with suppression of macrophage innate responses, this may contribute to the overall down-regulation of immune responses observed in asymptomatically infected patients

Hyperreactive onchocerciasis is characterized by a combination of Th17-Th2 immune responses and reduced regulatory T cells

<div><p>Clinical manifestations in onchocerciasis range from generalized onchocerciasis (GEO) to the rare but severe hyperreactive (HO)/sowda form. Since disease pathogenesis is associated with host inflammatory reactions, we investigated whether Th17 responses could be related to aggravated pathology in HO. Using flow cytometry, filarial-specific cytokine responses and PCR arrays, we compared the immune cell profiles, including Th subsets, in individuals presenting the two polar forms of infection and endemic normals (EN). In addition to elevated frequencies of memory CD4⁺ T cells, individuals with HO showed accentuated Th17 and Th2 profiles but decreased CD4⁺CD25^hiFoxp3⁺ regulatory T cells. These profiles included increased IL-17A⁺, IL-4⁺, RORC2⁺ and GATA3⁺CD4⁺ T cell populations. Flow cytometry data was further confirmed using a PCR array since Th17-related genes (IL-17 family members, IL-6, IL-1β and IL-22) and Th2-related (IL-4, IL-13, STAT6) genes were all significantly up-regulated in HO individuals. In addition, stronger <i>Onchocerca volvulus</i>-specific Th2 responses, especially IL-13, were observed <i>in vitro</i> in hyperreactive individuals when compared to GEO or EN groups. This study provides initial evidence that elevated frequencies of Th17 and Th2 cells form part of the immune network instigating the development of severe onchocerciasis.</p></div

Etude epidemiologique des accidents sur les lieux de travail dans une compagnie d’energie electrique au Togo

L’objectif de cette étude est de décrire le profil épidémiologique des  accidents sur les lieux de travail dans une compagnie d’énergie électrique au Togo. Il s’agissait d’une étude rétrospective menée du 1er janvier 2015 au 31 décembre 2016 au sein de la compagnie. Elle a pris en compte toutes les fiches de déclaration des accidents sur les lieux de travail durant la période. Les informations ont été recueillies au moyen d’une fiche de collecte préétablie ; l’analyse statistique a été réalisée avec le logiciel EPI Info version 3.5.3. Au total 73 Accident de travail (AT) ont été recensés durant les deux années soit 6,52% de l’effectif total. Les victimes,  majoritairement de sexe masculin (97,26%) avaient un âge moyen de 35,12 ± 10 ans, et moins de cinq ans d’ancienneté au poste (82,19%). Les ouvriers temporaires (57,53%) et les électriciens affectés aux postes techniques : branchement, dépannage et maintenance étaient les plus touchés (64,38%). Les contusions, les brûlures cutanées et les lumbagos prédominaient (respectivement 52,04%, 15,06% et 09,58%). Le siège des lésions était multiple (20,54%), aux mains (35,61%) et au tronc (16,8%). Les AT étaient dus au courant électrique (27,39%), au matériel électrique (24,65%) et aux outils à main (15,06%). 14% des victimes avaient  bénéficiés d’une incapacité temporaire de travail d’une durée moyenne de 5jours. Aucun AT mortel n’a été enregistré pendant la période. Des mesures de prévention s’imposent pour la réduction des AT au sein de la compagnie.Mots-clés : Accident du travail, épidémiologie, lieux de travail, Togo.  Epidemiological study of workplace accidents in an electricity  company in TogoThe objective of this study is to describe the epidemiological profile of accidents at the workplace in an electric power company in Togo. This was a retrospective study conducted from January 1, 2015 to December 31, 2016 within the company. She took into account all the accident report cards in the workplace during the period. The information was collected using a pre-established collection card; the statistical analysis was carried out with the software EPI Info version 3.5.3. A total of 73 accidents at work were recorded during the two years, that is 6.52% of the total workforce. The majority of male victims (97.26%) had an  average age of 35.12 ± 10 years and less than five years of seniority  (82.19%). Temporary workers (57.53%) and electricians assigned to technical positions: connection,  troubleshooting and maintenance were the most affected (64.38%). Bruises, skin burns and lumbago predominated (52.04%, 15.06% and 09.58% respectively). The site of lesions was multiple (20.54%), hands (35.61%) and trunk (16.8%). The accidents were due to electric current (27.39%), electrical equipment (24.65%) and hand tools (15.06%). 14% of the victims had a temporary work disability of an average duration of 5 days. No fatal workplace’s accident was recorded during the period. Preventive measures are  needed to reduce accidents within the company.Keywords: Occupational accident, epidemiology, workplace, Togo.

Comportements sexuels des collegiennes et lyceennes du departement du Borgou enquetees en 2020 : Sexual behavior among middle school and high school girls in the Borgou department surveyed in 2020

Introduction : Les rapports sexuels chez les adolescentes constituent un facteur de risque de grossesses non désirées et d’infections sexuellement transmissibles/VIH-SIDA. La présente étude avait pour objectif de déterminer la fréquence des rapports sexuels chez les lycéennes et collégiennes du département du Borgou et d’identifier les facteurs associés.Patients et Méthodes: Il s’est agi d’une étude transversale, descriptive et analytique qui s’était déroulée dans les lycées et collèges du département du Borgou. La population d’étude était constituée des collégiennes et lycéennes ayant donné leur consentement. L’analyse des données avait été faite à l’aide du logiciel Epi Info version 7 et p value inférieure à 5 % était considérée comme significative.Résultats : Au total 360 collégiennes et lycéennes avaient participé à l’étude. L’âge moyen était de 16,96 ± 1,98 ans. Parmi elles, 137 avaient des rapports sexuels soit une fréquence de 38,06 %. Les moyens contraceptifs étaient utilisés par 70,07 % des élèves. Les facteurs associés aux rapports sexuels chez collégiennes et lycéennes en analyse multivariée étaient l’âge de 15 ans et plus, les mariées, le fait d’avoir un copain, le deuxième cycle, vivre seul, les mauvaises relations avec les parents, l’absence de discussion du sexe avec les parents et les activités parascolaires.Conclusion : Les rapports sexuels non protégés sont observés chez certaines collégiennes et lycéennes du département du Borgou. Une sensibilisation sur la prévention des grossesses et infections sexuellement transmissibles/VIH-SIDA à leur endroit est indispensable. Introduction: Teenage sex is a risk factor for unwanted pregnancies and sexually transmitted infections/HIV-AIDS. The aim of the present study was to determine the frequency of sexual intercourse among high school and college girls in the department of Borgou and identify associated factors.Patients and Methods: This was a cross-sectional descriptive and analytical study that took place in high schools and colleges in the Borgou department. The study population consisted of middle school and high school students who had given their consent. Data analysis was done using Epi Info version 7 software and p value less than 5% was considered significant.Results: A total of 360 middle school and high school students participated in the study. The mean age was 16.96 ± 1.98 years. Among them 137 had sex and frequency of 38.06%. Contraceptives were used by 70.07% of the students. Factors associated with sex among middle school and high school girls in multivariate analysis were age 15 and over, brides, having a boyfriend, high school, living alone, poor relationship with parents, lack of discussion of sex with parents and extracurricular activities.Conclusion: Sexual intercourse not protected is observed in some middle school and high school girls in the department of Borgou. Awareness of the prevention of pregnancies and sexually transmitted infections in them is essential

Aspect epidemiologique de la perte auditive chez les travailleurs d’une industrie agroalimentaire a Lome au Togo

La surdité professionnelle constitue de par sa gravité un problème majeur dans le monde industriel. L’objectif était d’évaluer l’état auditif des travailleurs exposés au bruit dans une industrie agro-alimentaire à Lomé au Togo. Il s’agissait d’une étude transversale descriptive et analytique qui s’est déroulée du 1er décembre 2017 au 30 Juin 2018. Un mesurage des niveaux sonores a permis de réaliser la cartographie du bruit ; les tests audiométriques pour les opérateurs exposés au bruit ont été faits. Les données a été analysées avec le logiciel Sphinx Plus2 ; le test de Chi2 a permis les comparaisons avec un seuil de significativité de 5%. Au total 183 travailleurs dont deux de sexe féminin ont été inclus ; la moyenne d’âge et d’ancienneté au poste étaient de 40,4±8,9ans et de 7,4±6,7 ans. Le niveau de bruit dans l’entreprise variait entre 60 et 115dB (A) ; 25 postes sur les 30 étudiés ont un niveau de bruit ≥ 80dB. 37 cas (20,2%) de perte auditive ont été identifiés dont 3 sévères. Les facteurs associés étaient l’âge (p=0,0024), l’ancienneté (p=0,003), et le non port d’EPI (p=0,0015). Les niveaux de bruits et la perte auditive chez les employés dans cette industrie agroalimentaire sont élevés, un accent doit être mis sur la prévention. Mots clés : Bruit au travail, perte auditive, industrie agroalimentaire, Togo. &nbsp; English Title: Epidemiological aspect of hearing loss among workers in an food industry in Lomé, Togo Occupational deafness is a serious problem in the industrial world. The objective was to evaluate the auditory status of workers exposed to noise in a food company in Lomé, Togo. This was a descriptive and analytical cross-sectional study that took place from December 1st, 2017 to June 30th, 2018. A sound level measurement made it possible to carry out noise mapping; audiometric tests for operators exposed to noise have been made. The data was analyzed with the Sphinx Plus2 software; the Chi2 test allowed comparisons with a significance level of 5%. A total of 183 workers, two of whom were female; the average age and seniority at the position was 40.4 ± 8.9 years and 7.4 ± 6.7 years. The noise level in the company ranged from 60 to 115dB (A); 25 of the 30 stations studied have a noise level ≥ 80dB. 37 cases (20.2%) of hearing loss were identified, 3 of which were severe. Associated factors were age (p = 0.0024), seniority (p = 0.003), and non-wearing of PPE (p = 0.0015). The levels of noise and hearing loss amongemployees in this company in Togo are high, a focus should be on prevention. Keywords: Occupational noise, hearing loss, food industry, Togo