Subject(s)

Child, Preschool , Female , Humans , Infant , Male , Diarrhea/epidemiology , Respiratory Tract Infections/epidemiology , Virus Diseases/epidemiology , Acute Disease , Comorbidity , Diarrhea/virology , Influenza A virus/isolation & purification , Influenza, Human/epidemiology , Mexico/epidemiology , Poverty Areas , Prospective Studies , Respiratory Tract Infections/virology