[Seasonal variation of intestinal protozoa infections in outpatients of the north section of Santiago, Chile. 1995-1996].

Formalin preserved fecal samples from 6,058 and 5,863 outpatients were examined for intestinal parasites during 1995 and 1996 respectively. Prevalence rates of infections by intestinal protozoa in both years were similar. By age group (0-9, 10-19 and > 20 years old) Blastocystis hominis was observed in 18.6-19.3, 37.0-31.1 and 25.3-25.4% in 1995-1996 respectively. Prevalence of Giardia intestinalis infections decreased from 16.6-17.4% in the 0-9 year-old children group to 4.1-4.5% in patients over 20 years. Overall percentages of infection by Entamoeba histolytica varied between 4.2 and 10.9. Rates of infections by G. intestinalis, E. histolytica, and Entamoeba coli observed during rainy-cold months (april-september) of the year versus drywarmy period (october-march) were the same. On the contrary, more cases of B. hominis infection 25.8% versus 18.2% (this difference being statistically significant, p > 0.001) were observed during rainy-cold months of the year.