[Blastocystis hominis in Canavese: a retrospective study of samples received for fecal parasitological examination at the Ivrea- Castellamonte Hospital over 42 months].

In the last ten years the interest in the controversial Blastocystis hominis microorganism of the intestine has greatly increased. The authors conducted a retrospective study of feces for parasitology investigations at the Ivrea-Castellamonte hospital. These investigations lasted 42 months (1/1/1988-31/6/1991) and the authors focused their attention on samples with 5 or more Blastocystis hominis at the microscopically examination with a 40X phase objective. During the study 2,138 samples of feces (belonging to 1552 patients) arrived. 284 samples (13.3%), corresponding to 200 patients (12.9%), proved to be positive for one or more parasites. In 155 samples (7.2%) regarding 109 patients (7.0%)--53 males, 56 females--Blastocystis was present. These patients were between 2 and 78 years of age. In 19 (17.4%) of these patients other parasites were associated, parasites such as Giardia lamblia (in 6 cases), Entamoeba coli (in 4 cases), Entamoeba spp. (in 2 cases), Entamoeba histolytica (in one case), Entamoeba hartmanni (in one case), Iodamoeba butschlii (in one case), Hymenolepis nana (in one case); helminths (in 3 cases). The most effect proved to be those patients between 21 and 50 years of age (53 of 98 patients). Few infants were affected. The greatest incidence of Blastocystis hominis infection occurred during the months of January to June. The authors conclude by considering how the incidence data of such parasitosis in the Canavese region can be superimposed on as much as has been observed in territories which are very different regarding social-economic and geoclimatic conditions. The authors think it is necessary to start a prospective clinical-epidemiological investigation in the Canavese region with a view to defining the clinical approach to the parasite under discussion in a better way.