## 4 Discussion
A specific aim of the study was to provide new data on the microbiota composition in subjects harboring _Blackocystis_, _Entamoeba_ spp., and common enteropathogens. The high detection of protozoa viruses and bacteria confirmed data reported by previous studies conducted in the same area [26; 51] and other countries in sub-Saharan Africa [9; 19; 52; 53; 54]. No patients were tested positive for _E. Histolytica_, _C. hominis_, and _C. parvum_. Unfortunately, the use of the xTAG GPP molecular test did not allow the isolation of _Cryptosporidium meleagridis_ whose prevalence is relatively high in the same area [55]. The high number of asymptomatic individuals suggests an adaptation to constant and cumulative exposure to enteropathogens due to the common risk factors associated with low-income countries [56; 57; 22; 23; 58]. In children and adults carrying protozoa, bacteria, or viruses, greater diversity and richness in the gut microbiota than in negative subjects was evident, in line with other works [19; 20]. Furthermore, the critical taxa involved in the intestinal homeostasis such as _Faecalibacterium_, _Bifidobacterium_, _Lachospiraceae_, _Ruminococcaceae_ UCG-002, (_Eubacterium_) _coproostanoligenes_, (_Eubacterium_) _rectale_, and _Roseburia_ group showed variations in richness in the same comparison. The variable abundance of bacterial genera such as _Faecalibacterium_, _Bifidobacterium_, _Roseburia_ group allows for the production of key metabolites as short-chain fatty acids (SCFA), e.g., butyrate and succinate, lactate, or acetate to preserve homeostasis [1; 4; 59]. This scenario could reflect a bidirectional ability of adaptation between the host's immune response and bacterial composition. _Faecalibacterium prausnitzii_ and _E. redcale_ are responsible for a major fraction of butyrate production and consequently play a crucial role in shaping the local and peripheral immune system. The emerging evidence of diet-induced changes in SCFA-producing bacteria, as reported by [PERSON] et al. [60], could suggest a possible contribution of Ivorian eating habits in the modulation of adaptive immunity. _Blackocystis_ was highly prevalent in our cohort and a non-significant variation of alpha diversity between _Blackocystis_ positive-only group and the control group is evidence of the modest effect that _Blackocystis_ carriage has [61; 62]. The lower abundance of Bacteroides in subjects infected with _Blackocystis_ seems to confirm the hypothesis of a minor predisposition to harbor this parasite in \"Bacteroides-driven enterotype\" subjects, as described for Danish and Spanish individuals by [PERSON] et al. [63], and Mexican subjects by [PERSON] [64]. In all groups carrying _Blackocystis_, bacterial genera associated with a healthy status, such as _E. redcale_ and _coproostanoligenes_ groups, _Roseburia_ and _Succinibrio_ showed a constant presence, although with a reduced relative abundance versus control group [46; 67; 68; 69]. These specific OTUs could explain a beneficial influence on normbiosis [61] also in conjunction with a traditional African diet. Considering the genetic diversity within _Blackocystis_, with at least 17 different subtypes, the possible implications in the pathophysiology of human infections related to the different subtypes should be investigated to better understand the role of this parasite on the human gut microbiota [63; 69]. Concerning commensal _Entamoeba_ spp., an increase in alpha diversity in subjects co-harboring _Entamoeba_ spp. and _Blackocystis_, especially in case of _E. hartmanni_ co-occurrence, was evidenced. Clear separation in Unifrac distance was found and the increase of _Succinibrio_, _Christensenellaceae_ R-7 group, _Ruminococcaceae_ UCG-002, _Rikenellaceae_ RC9 intestinal group seem associable with _Entamoeba_ perturbations. Bacterial niches, responsible for beneficial or detrimental associations in subjects positive for _Blackocystis_ alone or co- harbored with commensal _Entamoeba_ spp., should be further investigated [70; 71].