Ecological characterization of interspecific relationships between human parasites: conflict, cooperation or independence?
During multiparasitism, the interspecific association among parasite species occur at the single host, population and community levels. Their detection and understanding are crucial to prevent and manage infectious diseases. In order to find out potential interspecific interactions among parasite species at a host population level, a cross-sectional study was carried out from September 2017 to July 2018 on schoolchildren aged from 4 to 15 years old; primary schools were randomly selected in the Nyong-et-Mfoumou Division. Stool samples and blood smears were analysed to detect parasitic forms of protozoa and helminths. Parasite interspecific associations were explored by ecological indices of association: Dice (D), Forbes (F) and tetrachoric coefficient (φ). The parasitological analysis revealed the presence of 13 parasite species belonging to 11 families, 9 orders, 7 classes and 5 phyla. A cooperation or positive association was found between E. coli and E. histolytica/dispar, A. lumbricoides and T. trichiura, E. coli and P. falciparum, E. histolytica/dispar and P. falciparum, E. coli and A. lumbricoides, and E. coli and T. trichiura. They co-occurred together more frequently than expected by chance. The conflict or negative association was noticed between G. intestinalis and both A. lumbricoides and T. trichiura, and between A. lumbricoides and P. falciparum. The independence was found between G. intestinalis and both E. histolytica/dispar and E. coli, and between M. perstans and En. nana, G. intestinalis, E. coli and E. histolytica/dispar. Further studies are needed to identify the real interaction mechanisms between parasite species and to evaluate the consequences of multiparasitism for both parasite species and the host.