For example, the titers of IgA antibodies in serum and saliva of individuals residing in Mexico who lived or not in endemic areas of this amoeba such as Ciudad Valles, San Luis Potosí, México, found that the recognition of N. fowleri proteins by serum and saliva IgA antibodies of people with upper respiratory tract infections (URTI) living in endemic areas were significantly higher compared to healthy individuals who are residents of the same area (Rivera et al. 2001). This evidence concerns the gene CD79A and Recurrent upper respiratory tract infections.