The overall prevalence of diarrhoea (15.9%) in the Taabo sub-prefecture was close to the national rate (17.9%) (INS, 2013). On the other hand, this prevalence was clearly higher than that observed in the peri-urban area of Abidjan (7%) (Koné et al. 2014). The higher prevalence of diarrhoea in rural areas compared to peri-urban areas could be explained by a number of factors related to the management of the immediate environment. Indeed, census data from the Taabo HDSS revealed that more than 70% of households did not have latrines and people relied mainly on surface water for daily needs (Schmidlin et al. 2013; Hürlimann et al. 2018; Coulibaly et al. 2018). All of these factors are believed to contribute significantly to the transmission and maintenance of diarrhoeal pathogens in rural communities (Pickering et al. 2015). Latrines reduce faecal contamination of the community environment and, with it, diarrhoeal morbidity (Root 2001). In addition, the consumption of safe water partially interrupts the transmission of diarrhea (Sy et al. 2017).
However, higher prevalence of diarrhoea than reported in our study have been obtained in sub-Saharan African countries, namely Mali (24%), Mauritania (23.6%), Senegal (26.1%), Burkina Faso (63.8%) (Nitiema et al. 2011; Touray et al. 2012; Pickering et al. 2015; Thiam et al. 2017).
The overall prevalence of the different digestive parasites is 17.3%, with 15.5% for Ancylostoma spp., 3.2% for Trichuris trichiura and 0.1% for Schistosoma mansoni and Ascaris lumbricoides. These prevalence differ from those found in the same area in 2012 (Fürst et al. 2012) and 2013 (Schmidlin et al. 2013). During these works, the authors recorded prevalence of 39% and 33.5% (Ancylostoma spp.), 2.7% and 1.6% (T. trichiura), 2.1% and 1.3% (S. mansoni) and 0.0% and 0.8% (A. lumbricoides), respectively. Except for T. trichiura, the prevalence we found in the Taabo sub-prefecture are decreasing compared to previous years. The decrease in the prevalence of hookworm, A. lumbricoides and S. mansoni can be explained by the various treatments that the population of Taabo sub-prefecture has undergone as part of the HDSS activities for the investigation and targeted control of neglected tropical diseases. These include annual albendazole treatment, Information Education Communication (IEC) and Community-Led Total sanitation (CLTS), conducted by researchers and Taabo HDSS staff (Fürst et al. 2012; Schmidlin et al. 2013; Righetti et al. 2013; Hürlimann et al. 2014, 2018; Koné et al. 2015; Glinz et al. 2017). It is worth noting that control and elimination activities of lymphatic filariasis, schistosomiasis and soil-transmitted helminths by the Ministry of Health are ongoing in our study localities (Coulibaly et al. 2018). But if the prevalence of hookworm is still high, this is due to the fact that this parasite has a very rapid capacity for reinfestation (Quinnell et al. 1993; Hotez et al. 2008; Jia et al. 2012). Indeed, capable of infestation by transcutaneous penetration, hookworms reinfest humans during their various work on the land (Yajima et al. 2009; Hürlimann et al. 2018). The high incidence of hookworm is due to the warm, humid, tropical region, suitable soil, sufficient oxygenation of our environment which favours the survival and dissemination of hookworm larvae (Yajima et al. 2009). The persistence of T. trichiura is due to the fact that this parasite is resistant to antihelmintic drugs such as albendazole(Müller et al. 2016; Barda 2022; Hürlimann et al. 2022).
Regarding the relationship between diarrhoea and parasitic diseases, T. trichiura was the only parasite species significantly associated with people suffering from diarrhoeal diseases. This would mean that this parasite is correlated with diarrhoea in the study area. In contrast, Ancylostoma spp. was significantly more common in individuals without diarrhoea. This finding suggests that this digestive pathogen is not involved in diarrhoeal disease. The same is true for S. mansoni and A. lumbricoides which were not present in individuals with diarrhoea. According to Gendrel et al. 2001, diarrhoea is not a common or even frequent symptom of parasitic infestations. In tropical areas, almost all children carry digestive parasites, but these cause only about 5% of acute diarrhoea and a few chronic diarrhoea if they are in good nutritional condition. In studies conducted in Burkina Faso and Senegal, viral infections were significantly more common in people with diarrhea (Nitiema et al. 2011; Sambe-Ba et al. 2013).
The limitations of this study were the failure to investigate other pathogens (viruses, bacteria, other intestinal parasites) likely to transmit diarrhoeal diseases; and epidemiological characteristics, as well as the risk and protective factors associated with the occurrence of diarrhoea in the study area.