Variações sazonais de bacteriófagos tífico-paratíficos nas águas dos rios da cidade de São Paulo

Abstract

The period of greater incidencc of typhoid and para typhoid A and B fever in S. Paulo is markedly in the summer months. The meteorologícal data observed show that this period coincides also·with lhe raíny season. Typhoid and para-typhoid A and B bacteriophages can be A and B isolated from the rivers Tietê and Pinheiros all lhe year around but only wilh difficulty during the winter months. Although lhe investigations on lhe hacteriophage have been made with selected races some were more sensible to lysis than others while this sensibility may vary from one test to the other. Typhoid and para-typhoid A and B bacteriophages were found in greater concentrations in the Pinheiros than in lhe Tietê river. The lylic action of the waters of both rivers on lhe typhoid anrl paratyphoid bacilli dicreases during the cold and increases during thc warm months. The rainy scason in S. Paulo coincides with the warm months the typhoid and para-typhoid bacteriphages grow more numerous, from the beginning of lhe rains, in accordance with the incidence of these infections. However, exactly at lhe time of the heavicr rains -- which is the period of highest incidenee of thsese infections -- there is a sudden fall in the number of these hacteriophages, which however is relative, depending on the grater volume of the water.