“…However, in other States, where the DEN-2 virus circulated after extensive epidemics caused by DEN-1, as in Rio de Janeiro, Ceará, Pernambuco, and Rio Grande do Norte, an increase in the number of severe cases was observed. Beginning with the introduction of DEN-2 virus in 1990, a total of 754 DHF/DSS cases were reported, with 34 deaths, as of the 39th epidemiological week, and it is believed that there may have more cases that were not officially confirmed (Nogueira et al, 1990;Zagne et al, 1994;Souza et al, 1995;Vasconcelos et al, 1995).…”