To present the transition and epidemiological relevance of Blastocystis spp. since in recent years it has surpassed the behavior of Giardia lamblia, positioning itself as the most frequent parasite reported in Mexico.

The prevalence of G.lamblia and Blastocystis spp. was comparatively analyzed through a retrospective search from 2000-2021, compiling all the articles referring to these agents in 30 different search engines (Pubmed, Scopus, among others). It was used officials of the Consejo Nacional de Fomento Educativo (CONAFE) and the Consejo Nacional de Evaluación de la Política de Desarrollo Social (CONEVAL) to learn about the behavior of these parasites.

The transition in the prevalence of Blastocystis spp. on G.lamblia, however the reason is still not clear despite the fact that various hypotheses have been formulated, likewise, due to the limited number of articles in Mexico, the importance of this parasitosis is underestimated.