No abstract

Beginning in 1988, the incidence of meningococcal disease in the area of greater São Paulo began to surpass the upper confidence limit of an 8-year average incidence (from 1979 to 1986), thus characterizing a new epidemic in the region of greater São Paulo. This epidemic, which extended to 1990, was different from previous epidemics in that it was caused by serogroup B. The increased incidence of meningococcal disease was paralleled by an increased prevalence of a single group B clone, B:4:P1.15, of the ET-5 complex. ET-5 strains have been present in the greater São Paulo area since 1979; however, they have been associated with a high percentage of the group B disease only from 1987 to the present. On the basis of the increased incidence of group B disease in São Paulo, a mass vaccination program with a serotype 4:P1.15 meningococcal protein vaccine was undertaken. The impact of this vaccination program is under analysis.

The hantavirus pulmonary syndrome was first recognized in cases that occurred in the U.S. in 1993, which served as an alert not only for American physicians but also for physicians in other countries for the identification of the disease. In the city of São Paulo, Brazil, 3 cases of the syndrome were recorded in 1993. The patients were young brothers residing in the Mata Atlântica (Atlantic Forest) region submitted to recent deforestation. Two of the patients died of acute respiratory insufficiency and the third recovered without sequelae. In the surviving patient the diagnosis was established by a laboratory criterion based on the detection of specific IgM and IgG class antibodies by indirect immunofluorescence. In the two patients who died, the diagnosis was confirmed by laboratory tests using immunoperoxidase technique for hantavirus in tissue, in histological lung and heart sections in one case, and by clinical and epidemiological data in the other.

Serogroup C isolates of Neisseria meningitidis recovered from 121 patients with meningitis or septicemia in Greater Sao Paulo, Brazil, between 1976 and 1990 were analyzed with respect to serotype and multilocus enzyme genotype. The distribution of serotypes has changed since 1989 when serotype 2b started to replace serotype 2a. There were 48 distinct multilocus genotypes (electrophoretic types [ETs]) and 13 distinct complexes. Among the 41 serotype C:2b:-strains analyzed, 38 (93%) were found in complex 11. The percentage of complex 11 increased from 8% in 1988 to 50 and 66% in 1989 and 1990, respectively. Although we have been in an epidemic situation due to serogroup B:4:P1.15 ET-5 complex since 1988, the appearance and increase of a new unrelated strain, C:2b:-of ET-1l complex, in 1989 and 1990 provide enough data to conclude that the presence of two different complexes, ET-5 and-11, of N. meningitidis were responsible for the high levels of meningococcal disease in Greater Sao Paulo during this period.

The prevalence of rubella antibodies was evaluated through a ramdom Seroepidemiological survey in 1400 blood samples of 2-14 year old children and in 329 samples of umbilical cord serum. Rubella IgG antibodies were detected by ELISA, and the sera were collected in 1987, five years before the mass vaccination campaign with measles-mumps-rubella vaccine carried out in the city of São Paulo in 1992. A significant increase in prevalence of rubella infection was observed after 6 years of age, and 77% of the individuals aged from 15 to 19 years had detectable rubella antibodies. However, the seroprevalence rose to 90.5% (171/189) in cord serum samples from children whose mothers were 20 to 29 years old, and reached 95.6% in newborns of mothers who were 30 to 34 years old, indicating that a large number of women are infected during childbearing years. This study confirms that rubella infection represents an important Public Health problem in São Paulo city. The data on the seroprevalence of rubella antibodies before the mass vaccination campaign reflects the baseline immunological status of this population before any intervention and should be used to design an adequate vaccination strategy and to assess the Seroepidemiological impact of this intervention.