Reciprocal regulation of immune responses to S. haematobium and P. falciparum in double-infected populations in Northern Senegal.
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.