Isolation of dengue viruses from hospitalized patients in the Philippines, 1983-1986.

: Between 1983-1986, 336 strains of dengue virus were isolated from 1,911 patients who had been hospitalized with clinically suspected DF/DHF in Manila and nearby areas. Multiple serotypes were present every year. Although DEN 3 was the most common serotype isolated (40%) over the entire study period, DEN 2 and DEN 1 were more frequently isolated in 1983 and 1984, respectively. DEN 4 was consistently the least common serotype recovered. During 1984, geographic differences in the pattern of serotypes isolated were found for two heavily populated areas located only 70 km apart. A higher proportion of DEN 2 isolates were recovered from patients with gastrointestinal bleeding compared to DEN 1 and DEN 3. A higher proportion of DEN 1 and DEN 3 isolates came from patients experiencing a 1 degree infection compared to DEN 2, and the mean homologous HI antibody titer of the sera that DEN 2 was isolated from was significantly higher than the homologous titers of sera from which DEN 1 and DEN 3 were isolated.