Epidemiologic and bacteriological study of epidemic cerebro-spinal meningitis in the city of S. Paulo, Brasil

Abstract

Epidemiology Cerebro-spinal meningitis has been observed and continues to appear in S. Paulo as an endemic disease. There has been no epidemic increase but only a greater number of cases in certa in. occasions. The morbidity coefficient for 100.000 inhabitants is low, whereas the mortality has been at times rather high, reaching in 1926, 60.5% of the number of patients. However, the average for the years 1920-1928 is only o f 39% fatal cases, including, untreated, serum treated cases, and cases treated only in extremis. Tables are given showing the principal meteorological fac· ors affecting the morbidity, and the mortality in this locality. Here also the cerebro spinal-meningitis is more frequent tn the winter, which in S. Paulo does not coincide with the raiiny months, nor with the greater humídity of the air, both of which are observed in the warmer months. In Europe, the cold comes in the rainy months, when the humidity is also greatest, and in many localities these three factors are noted as very important or even as essential to the appearance of meningococcus meningitis. In S. Paulo the cold is the only factor which can be considered as of any importance. Bacteriology Morplzological characters - Since ali Neisserias are able to cause meningitis, even Neisseria gonorrhea (gonococcus), and since their morphological characters are almost identical and they are Gram-negative, it is bes t to classify them in accordance to their cultural characters and especially by means of the most important of their biological properties that of fermenting carbohydrates. The agglutination test may help to differentiate these bacteria, but there is some doubt about the serological fypes of the meningococcus and it is possible to find non agglutinating meningococci when they have been recently isolated. Fermentation- There is a careful study of the indicator, the carbohydrates, their sterilization and the choice of a medium. Neutral red was the indicator which gave the best results. Rosolic acid does not favour the growth o f meningococci; pherzoled gives good resuUs, but somewhat inferior to those obtained vith neutral red. lhe sterilisation o f the carbohydrates at 1OOoC. for 1Om. 1r their intermittent sterilisation for 3 successive days at 1 OOoC. 1roduced no change in them, whereas sterilisation at 1OOoC. for lOm. caused a change in Ievulose. Media- We prefer a solid medium. The growth is very low in a Jiquid medium and it is very difficult to observe fernentation even after 48 hrs. lhe fermentation is quite clear with the meningococcus nd any other Neisseria after 6 hrs. in the incubator, when the nedium recommended is used, and when it is inoculated as in· licated.