44, p = 0.001). The increases in the maximum temperature had no significant effect on the attack rate. In contrast to the rates for ETEC, the rates of EAEC-associated diarrhea remained relatively constant despite seasonal temperature variations (p = 0.1). TD is caused by a variety of bacterial agents of which ETEC and EAEC are the most common identifiable pathogens.1

In agreement with the previously published studies on TD acquired in Guadalajara, Mexico from 1986 to 19899, this see more study found that the rates of TD were higher during summertime when compared to wintertime in central Mexico. This second study was conducted in Cuernavaca, Mexico, which is called “the city of eternal springtime” where temperature variations are milder. The warmer and wetter summer months are associated with an increased occurrence of diarrhea.12 Warmer climates may encourage propagation of enteric bacterial pathogens in food13 and water14 explaining the increase in bacterial diarrhea during Volasertib molecular weight the summertime. Furthermore, in the case of ETEC, seasonality also appears to influence the rates of identified toxin phenotypes. It has previously been suggested that in Egypt, ST (heat-stable toxin)-producing ETEC strains are more commonly identified in the stools of children with diarrhea in the summer, whereas LT

(heat-labile toxin)-producing ETEC strains are identified all year around.15 In our study, the rates of LT- and ST-producing ETEC did not appear to vary according to seasonality. In this study, we found that minimum and average temperatures are positively associated to higher rates of ETEC-associated diarrhea. We hypothesize that since weekly maximum temperatures do not fluctuate as much as minimum temperatures, Fossariinae the analysis failed to show a statistical correlation with maximum temperatures. When studied in the univariate analysis, the identification of STEC as defined by the

presence of stx1 or stx2 in stools also showed a positive correlation with warmer temperature and summertime diarrhea, however only ETEC showed a significant correlation when an adjusted multivariate analysis was performed. An important observation in this study is that in contrast to ETEC, the rates for EAEC, the second most common bacterial cause of TD, remained similar in both seasons. This is consistent with a previous study carried out in Korea that failed to find a seasonal pattern for EAEC infection16 and contrasts with a 12-month study in a US pediatric population, where Cohen and colleagues reported a seasonal peak of EAEC in children during March to April months; However, a confounding variable in that study was that many of the EAEC cases were coinfected with Rotavirus.4 Although EIEC was only identified in the summer, additional studies are needed to determine if the occurrence of EIEC infection is also seasonal.