Schistosomiasis Coinfection in Children Influences Acquired Immune Response against Plasmodium falciparum Malaria Antigens

Background: Malaria and schistosomiasis coinfection frequently occurs in tropical countries. This study evaluates the influence of Schistosoma haematobium infection on specific antibody responses and cytokine production to recombinant merozoite surface protein-1-19 (MSP1-19) and schizont extract of Plasmodium falciparum in malaria-infected children. Methodology: Specific IgG1 to MSP1- 19, as well as IgG1 and IgG3 to schizont extract were significantly increased in coinfected children compared to P. falciparum mono-infected children. Stimulation with MSP1- 19 lead to a specific production of both interleukin-10 (IL-10) and interferon-c (IFN-c), whereas the stimulation with schizont extract produced an IL-10 response only in the coinfected group. Conclusions: Our study suggests that schistosomiasis coinfection favours anti-malarial protective antibody responses, which could be associated with the regulation of IL-10 and IFN-c production and seems to be antigen-dependent. This study demonstrates the importance of infectious status of the population in the evaluation of acquired immunity against malari

Low and seasonal malaria transmission in the middle Senegal River basin: identification and characteristics of Anopheles vectors

<p>Abstract</p> <p>Background</p> <p>During the last decades two dams were constructed along the Senegal River. These intensified the practice of agriculture along the river valley basin. We conducted a study to assess malaria vector diversity, dynamics and malaria transmission in the area.</p> <p>Methods</p> <p>A cross-sectional entomological study was performed in September 2008 in 20 villages of the middle Senegal River valley to evaluate the variations of <it>Anopheles </it>density according to local environment. A longitudinal study was performed, from October 2008 to January 2010, in 5 selected villages, to study seasonal variations of malaria transmission.</p> <p>Results</p> <p>Among malaria vectors, 72.34% of specimens collected were <it>An. arabiensis</it>, 5.28% <it>An. gambiae </it>of the S molecular form, 3.26% M form, 12.90% <it>An. pharoensis</it>, 4.70% <it>An. ziemanni</it>, 1.48% <it>An. funestus </it>and 0.04% <it>An. wellcomei</it>. <it>Anopheles </it>density varied according to village location. It ranged from 0 to 21.4 <it>Anopheles</it>/room/day and was significantly correlated with the distance to the nearest ditch water but not to the river.</p> <p>Seasonal variations of <it>Anopheles </it>density and variety were observed with higher human biting rates during the rainy season (8.28 and 7.55 <it>Anopheles </it>bite/man/night in October 2008 and 2009 respectively). Transmission was low and limited to the rainy season (0.05 and 0.06 infected bite/man/night in October 2008 and 2009 respectively). During the rainy season, the endophagous rate was lower, the anthropophagic rate higher and L1014F kdr frequency higher.</p> <p>Conclusions</p> <p>Malaria vectors are present at low-moderate density in the middle Senegal River basin with <it>An. arabiensis </it>as the predominant species. Other potential vectors are <it>An. gambiae </it>M and S form and <it>An. funestus</it>. Nonetheless, malaria transmission was extremely low and seasonal.</p

Seasonal and nutritional modulation of children's immune response to vaccines in the frame of the Expanded Program on Immunization of the WHO

La réponse immunitaire, qu’elle soit générée suite à un contact naturel avec un agent infectieux ou après l’administration d’un vaccin, est sujette à des variations qui peuvent être dues à des facteurs environnementaux tels que les infections ou la malnutrition.Au cours de ce travail, nous avons étudié par une approche épidémiologique, l’influence des variations saisonnières et de la malnutrition sur la réponse immunitaire vis-à-vis de vaccins administrés aux enfants avant l’âge d’un an dans le cadre du Programme Elargi de Vaccination de l’Organisation Mondiale de la Santé (coqueluche, tétanos, diphtérie, tuberculose).Une étude longitudinale multidisciplinaire de terrain a été menée au nord du Sénégal, dans 5 villages de la vallée du Grand Fleuve, sur une cohorte de 410 enfants âgés de 1 à 9 ans. Des visites ont été réalisées dans l’ensemble des villages, à différents moments de l’année, englobant des périodes de saisons sèches et de saisons humides, afin de collecter des données parasitologiques, cliniques et anthropométriques, ainsi que des échantillons sérologiques. Dans le cadre de la santé publique, cette étude a permis d’apporter des données régionales sur la couverture vaccinale, la prévalence du paludisme et de l’état nutritionnel des enfants.La réponse immune à la coqueluche a été mesurée par le dosage d’anticorps dirigés contre la toxine de la coqueluche et l’hémagglutinine filamenteuse, deux antigènes de la bactérie Bordetella pertussis, l’agent principal de la coqueluche. Nos résultats concernant la réponse humorale à ces antigènes indiquent des variations du taux d’anticorps en fonction de l’âge des enfants ainsi que de leur village de résidence. La séroprévalence à B. pertussis a révélé la circulation endémique de la bactérie dans certains villages avec l’apparition d’un pic épidémique dans l’un d’entre eux. De plus, nos analyses suggèrent que la malnutrition est associée à une diminution de la réponse humorale aux antigènes de la coqueluche et que le retard de croissance influe sur la séroconversion vis-à-vis de cette infection bactérienne. Par ailleurs, le retard de croissance semble diminuer la capacité des cellules immunitaires des enfants à produire de l’interféron gamma, une cytokine clé intervenant dans la défense contre les infections, en réponse à des antigènes vaccinaux. Les conséquences à plus long terme de la malnutrition chronique infantile sur le maintien ou le développement des réponses immunes chez ces enfants lorsqu’ils seront plus âgés demeurent un point important à étudier.Mots-clés : anticorps, vaccination, coqueluche, Bordetella, malnutrition, SénégalImmune response, whether generated as a result of natural contact with an infectious agent or after the administration of a vaccine, is subject to changes, which may be due to environmental factors such as infections or malnutrition.In this work, we used an epidemiological approach to study the influence of seasonal variations and malnutrition on the immune response to vaccines administered to children before the age of one, in the frame of the Expanded Programme on Immunization set up by the World Health Organization (whooping cough, tetanus, diphtheria, tuberculosis).A longitudinal multidisciplinary study was conducted in northern Senegal in 5 villages of the Great River valley, on a cohort of 410 children aged 1 to 9. Visits were conducted in all villages at different times of the year, including periods of the dry season and wet season, to collect parasitological, clinical and anthropometric data, as well as serological samples. In the context of public health, this study provides regional data on immunization coverage, malaria prevalence, and nutritional status of children

RESEARCH Open Access Prevalence and intensity of urinary schistosomiasis among school children in the

Background: Urinary schistosomiasis is a parasitic disease that exists in all regions of Senegal. It is a major public health issue in this country. This study was carried out to determine the prevalence and intensity of this parasitosis in 12 villages of Niakhar (Fatick, Senegal). Methods: A total of 210 schoolchildren, aged 7 to 15 years, were enrolled in this study, and urine samples were examined for Schistosoma haematobium eggs using a standard urine filtration technique. Results: Of these children, 121 (57.6%) were found to be infected with a mean geometric count of 185 eggs per 10 ml of urine. The disease was present in all surveyed villages, and the prevalence ranged from 14.3 % to 92.8%. The prevalence of infection was significantly correlated with increasing age and was higher in boys. Infection intensity was significantly higher in boys but did not significantly differ with age. Significant relationships between i) water contact or access to running water and ii) the prevalence or intensity of urinary schistosomiasis were also noted. Conclusions: The district of Niakhar is endemic for urinary schistosomiasis, with a high intensity of infection. A control program to decrease the prevalence and intensity should be implemented in this area to improve community health

Children of Senegal River Basin show the highest prevalence of Blastocystis sp. ever observed worldwide.

International audienceBACKGROUND: Blastocystis sp. is currently the most common intestinal protist found in human feces and considered an emerging parasite with a worldwide distribution. Because of its potential impact in public health, we reinforced the picture of Blastocystis sp. prevalence and molecular subtype distribution in Africa by performing the first survey of this parasite in Senegal. METHODS: Stool samples from 93 symptomatic presenting with various gastrointestinal disorders or asymptomatic children living in three villages of the Senegal River Basin were tested for the presence of Blastocystis sp. by non-quantitative and quantitative PCR using primer pairs targeting the SSU rDNA gene. Positive samples were subtyped to investigate the frequency of Blastocystis sp. subtypes in our cohort and the distribution of subtypes in the symptomatic and asymptomatic groups of children. RESULTS: By the use of molecular tools, all 93 samples were found to be positive for Blastocystis sp. indicating a striking parasite prevalence of 100%. Mixed infections by two or three subtypes were identified in eight individuals. Among a total of 103 subtyped isolates, subtype 3 was most abundant (49.5%) followed by subtype 1 (28.2%), subtype 2 (20.4%) and subtype 4 (1.9%). Subtype 3 was dominant in the symptomatic group while subtypes 1 and 2 were detected with equal frequency in both symptomatic and asymptomatic groups. The distribution of subtypes was compared with those available in other African countries and worldwide. Comparison confirmed that subtype 4 is much less frequently detected or absent in Africa while it is commonly found in Europe. Potential sources of Blastocystis sp. infection including human-to-human, zoonotic, and waterborne transmissions were also discussed. CONCLUSIONS: The prevalence of Blastocystis sp. in our Senegalese population was the highest prevalence ever recovered worldwide for this parasite by reaching 100%. All cases were caused by subtypes 1, 2, 3 and 4 with a predominance of subtype 3. More than half of the children infected by Blastocystis sp. presented various gastrointestinal disorders. Such high prevalence of blastocystosis in developing countries makes its control a real challenge for public health authorities

Risk of Zika virus transmission in the Euro-Mediterranean area and the added value of building preparedness to arboviral threats from a One Health perspective

Abstract In the alarming context of risk of Zika virus (ZIKV) transmission in the Euro-Mediterranean area, there is a need to examine whether capacities to detect, diagnose and notify ZIKV infections in the region are in place and whether ongoing capacity-building initiatives are filling existing gaps. The MediLabSecure network, created in 2014, comprises 55 laboratories of virology and medical entomology and 19 public health institutions in 19 countries in the Balkans, North-Africa, the Middle-East and the Black Sea regions. It aims to set up awareness, risk assessment, monitoring and control of emerging and re-emerging vector-borne viruses. We here examine the actions and strategies that MediLabSecure has been implementing and how they will contribute to the prevention and control of the ZIKV threat in the Euro-Mediterranean area. Capacity-building for arbovirus diagnostics is a major objective of the project and follows a methodological rather than disease-driven approach. This enables the implementation of laboratory trainings on techniques that are common to several arboviruses, including ZIKV, and putting into action appropriate diagnostic tools in the target region. Moreover, by its One Health approach and the interaction of its four sub-networks in human virology, animal virology, medical entomology and public health, MediLabSecure is fostering intersectoral collaboration, expertise and sharing of information. The resulting exchanges (methodological, communication and operational) across disciplines and across countries, dedicated research on intersectoral collaboration and increasing diagnostic capacities are providing new paths and tools to public health professionals to face emerging viral threats such as a ZIKV epidemic in the Euro-Mediterranean region

Molecular epidemiology of Blastocystis in Lebanon and correlation between subtype 1 and gastrointestinal symptoms.

International audienceBlastocystis is the most common eukaryotic parasite in the intestinal tract of humans. Because of its potential impact in public health, we acquired the first data concerning the prevalence of this parasite and the frequency of the Blastocystis subtypes (STs) in the Lebanese population. In this study, fecal samples from 220 Lebanese symptomatic and asymptomatic patients were collected and a total of 42 patients (19%) were identified as positive for this parasite by direct-light microscopy of smears. Among these, 36 Blastocystis isolates were genotyped using partial small subunit ribosomal RNA gene sequencing. The ST distribution in the present Lebanese population was as follows: ST3 (33.3%), ST2 (33.3%), ST1 (30.6%), and ST4 (2.8%). These data were compared with those available in other Middle Eastern and neighboring countries. Finally, ST1 was significantly more prevalent among symptomatic patients of this Lebanese population