Études et publications

Sarr JB, Remoue F, Samb B, Dia I, Guindo S, Sow C, Maiga S, Tine S, Thiam C, Schacht AM, Simondon F, Konate L, Riveau G.

Malaria Journal., 2007, 6:117-125 (PMID : )

In sub-Saharan areas, malaria transmission was mainly ensured by Anopheles. gambiae s.l. and Anopheles. funestus vectors. The immune response status to Plasmodium falciparum was evaluated in children living in two villages where malaria transmission was ensured by dissimilar species of Anopheles vectors (An. funestus vs An. gambiae s.l.). METHODS: A multi-disciplinary study was performed in villages located in Northern Senegal. Two villages were selected: Mboula village where transmission is strictly ensured by An. gambiae s.l. and Gankette Balla village which is exposed to several Anopheles species but where An. funestus is the only infected vector found. In each village, a cohort of 150 children aged from one to nine years was followed during one year and IgG response directed to schizont extract was determined by ELISA. RESULTS: Similar results of specific IgG responses according to age and P. falciparum infection were observed in both villages. Specific IgG response increased progressively from one-year to 5-year old children and then stayed high in children from five to nine years old. The children with P. falciparum infection had higher specific antibody responses compared to negative infection children, suggesting a strong relationship between production of specific antibodies and malaria transmission, rather than protective immunity. In contrast, higher variation of antibody levels according to malaria transmission periods were found in Mboula compared to Gankette Balla. In Mboula, the peak of malaria transmission was followed by a considerable increase in antibody levels, whereas low and constant anti-malaria IgG response was observed throughout the year in Gankette Balla. CONCLUSION: This study shows that the development of anti-malaria antibody response was profoundly different according to areas where malaria exposure is dependent with different Anopheles species. These results are discussed according to i) the use of immunological tool for the evaluation of malaria transmission and ii) the influence of Anopheles vectors species on the regulation of antibody responses to P. falciparum.

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Bonnard P, Remoué F, Schacht AM, Pialoux G, Riveau G.

The Journal of Infectious Diseases, 2006, 193 : 748-750 (PMID : 16453272)

In the 1 August 2005 issue of the Journal, Coutinho et al. described, in patients infected by Schistosoma japonicum, a correlation between the levels of certain cytokines and the presence of hepatic fibrosis (HF) [1]: they found that the levels of both interleukin (IL)–1 and IL-6 were higher in patients with HF than in patients without HF, and they also reported that the presence of HF was negatively correlated with body-mass index...

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Diallo TO., Remoué F., and Riveau G.

Update in Tropical Immunology, 2005, 221-233 (PMID : ISBN 81-308-0046-2)

Concomitant or associated infections refer to co-infections in which at least two infectious agents coexist in the same host and are specifically indicated as being genetically different. For individuals living in tropical or subtropical areas, such as Africa, concomitant infections are commonplace. Indeed, co-existing parasitic infections prevail in these areas and are supported by the constant movement of populations, anthropogenic changes but also ecological transformations. Among these cases, co-infections of malaria and helminthiasis are major in Africa and their respective influence on immunity could have consequences for both infection/morbidity developments. The main objective of our immuno-epidemiological approaches, performed in Senegal and presented here, was to evaluate the influence of Plasmodium falciparum and Schistosoma haematobium co-infection on the specific immune responses against these two parasites. The effect on the circulating level of inflammatory immune parameters associated with malaria/schistosomiasis morbidity was also assessed in human populations. In both children and adults, co-infection appeared to be in favour for the increase of acquired protective immune responses specific to malaria and schistosomiasis antigens. Concerning the circulating immune factors associated with both parasite pathologies, co-infection regulated the unbalance between the pro and anti-inflammatory cytokines which could act as harmful effects on the development of malaria/schistosomiasis pathology. Concomitant co-infection could thus orientate_ specific immune responses to an anti-infectious protective profile but could also increase the production of immune parameters associated with morbidity. The multi-infectious status observed in individuals from developing countries could have a major influence on the immune-dependent development of pathologies. This status has to be considered for the control, such as vaccine strategies, ofmajor parasitic diseases.

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