Contribution to the study of the place of protozoan parasites in the etiology of enteritis in the human population in hospital and non-hospital environment from urban and rural areas via animal sources

Abstract

In order to determine the frequency of different parasitic species and to identify for the first time the subtypes of Blastocystis spp. in the Algerian steppe area, a descriptive and analytical study of human intestinal parasitosis carried out on the set of 2277 patients, representative of urban and rural areas over a period of three years was realized in the wilaya of Laghouat. Each sample was subjected to direct microscopic examination, an enrichment, and in vitro culture on two xenic mediums. Subsequently 30 samples of Blastocystis positive culture were subtyped by PCR using sequencetagged site (STS) primers. Results indicated that the overall infection rate was 33,33%. Blastocystis spp is the most frequently found parasite (52,22%), followed by Entamoeba histolytica/dispar (26,35%), Giardia intestinalis (12,65%), Entamoeba coli (12,38%), Endolimax nana (5,27%), Trichomonas intestinalis (3,03%), Enterobius vermicularis (1,71%), Cryptosporidium spp (0,92%), Teania saginata (0,53%) and Trichuris trichuira (0,13%). Subtyping of Blastocystis spp indicated a high frequency of ST1 (63.3%), followed by ST4 (23.3%), ST2 (13.3%), ST7 (13.3%), ST3 (10%) and ST5 (6.7%). Mixed subtypes were identified in 30% (9/30) of analyzed samples. Clinical symptomatology is observed in 80,4% of the parasitized subjects and the parasite intensity were significantly correlated with the clinical signs. Multivariate analysis indicates significant associations between ST1, ST4 and residential places, between ST1, ST2, ST4, ST7 and patients who consume tap water and between ST1, ST2, ST4 and patients who are in contact with animals. To the best of our knowledge, this is the first report on subtyping of Blastocystis in Algeria.