Blastocystis hominis is an enteric emergen organism found in human it's prevalence has been increasing in the lasts years. The frequency in Mexico is from 4.0% to 62%, without reports in the Guerrero state. The aim of this study was to inform the parasitic transition to B. hominis in the Central Zone of Guerrero state. The population in this study were three communities of Guerrero state: Chilpancingo, Petaquilla and Tixtla in a total of 1,138 preschools and schools children of both sexs. Three parasitological tests were used for detection of the parasite in stool specimens: micrscopy of direct smears, concentration and flotation technique and serum-solution saline culture. Global prevalence of parasites was of 38% and B. hominis was the principal parasite with 61% on the positive tests. The 90% were only B. hominis and 10% with others parasites. A total of 58% of the children healthy with B. hominis declarated have gastrointestinal symptoms. The association of B. hominis with abdominal pain and drinking taste water had significant difference. We propuse a parasitic transition to B. hominis as principal human parasite, this can be the result of man-made intervention in the intestinal parasitosis control.

Dissertação apresentada ao Instituto de Ciências Matemáticas de São Carlos-USP, como parte dos requisitos para a obtenção do titulo de mestre em "Ciências de Computação e Matemática Computacional".