Background Intestinal parasitic infections are amongst the most common infections worldwide and have been identified as one of the most significant causes of morbidity and mortality among disadvantaged populations. This comparative cross-sectional study was conducted to assess the prevalence of intestinal protozoan infections and to identify the significant risk factors associated with intestinal parasitic infections in Laghouat province, Southern Algeria. Methods A comparative cross-sectional study was conducted, involving 623 symptomatic and 1654 asymptomatic subjects. Structured questionnaires were used to identify environmental, socio demographic and behavioral factors. Stool specimens were collected and examined using direct wet mount, formalin-ether concentration, xenic in vitro culture and staining methods. Results A highly significant difference of prevalence was found between symptomatic (82.3%) and asymptomatic subjects (14.9%), with the majority attributable to protozoan infection. The most common species in the symptomatic subjects were Blastocystis spp. (43.8%), E. histolytica/dispar (25.4%) and Giardia intestinalis (14.6%) and more rarely Enterobius vermicularis (02.1%), Teania spp. (0.6%) and Trichuris trichiura (0.2%), while in asymptomatic population Blastocystis spp. (8%), Entamoeba coli (3.3%) and Entamoeba histolytica/dispar (2.5%) were the most common parasites detected with no case of helminth infection. Multivariate log-linear analysis showed that contact with animals was the main risk factor for transmission of these protozoa in both populations. Furthermore, living in rural areas was significantly associated with combined protozoan infection in the asymptomatic population, whereas, in the symptomatic population an increasing trend of protozoan infection was detected in the hot season. In addition, Blastocystis spp. and G. intestinalis infection were found to be associated with host sex and contact with animals across the study period. Conclusions Based on these results, several strategies are recommended in order to effectively reduce these infections including good animal husbandry practices, health education focused on good personal hygiene practices and adequate sanitation.

Background: Intestinal parasitic infections are amongst the most common infections worldwide and have been identified as one of the most significant causes of morbidity and mortality among disadvantaged populations. This community based study was conducted to assess the magnitude and pattern of intestinal parasitism and to identify the key risk factors associated with intestinal parasitic infections in Laghouat province, south Algeria.Methods: Stool samples were collected from 2277 symptomatic and asymptomatic patients aged 1-89 years old. Structured questionnaire were used to identify environmental, socio demographic and behavioral factors. Stool specimens were collected and examined for intestinal parasitic infection. Results: More than 33% of participants were found to be infected for at least one protozoan and/or helminth parasite. Of these, the most common parasites were Blastocystis spp. (17.79%), followed by Entamoeba histolytica/dispar (8.78%), Giardia intestinalis (4.22%), Entamoeba coli (4.08%) and more rarely Endolimax nana, Cryptosporidium spp, Trichomonas intestinalis, Enterobius vermicularis, Taenia spp., and a single case of Trichuris trichiura. Multivariate analysis revealed significant associations between prevalence and species richness of combined protozoan parasites and contact with animal, living in rural areas and relying primarily on tap water, particularly in young individuals. Analysis of temporal consistency showed a high rate of infection in rural locations in the spring of 2018 and a firm relationship between school children and tap water was also detected. Conclusions: The high prevalence of intestinal parasitic infections among the Laghouat population, with identification of several risk factors indicates that parasitic infections are important public health problems. Therefore, several strategies are recommended in order to effectively reduce these infections including good animal husbandry practices, health education focused on good personal hygiene practices especially for school children, availability of safe drinking water and adequate sanitation.