Epidemiological study of Dengue infections in patients attended in a Public General Hospital, in Rio de Janeiro City, Brazil, during the outbreak of 2001-2002

ABSTRACT

From November of 2001 until April of 2002, a total of 1124 blood samples were collected from patients suspected of dengue infection attendedin the Hospital Municipal Paulino Werneck (HMPW), Ilha do Governador, Rio de Janeiro, Brazil. The samples were used for anti-dengue IgM and IgG detection, virus isolation, RT-PCR and Real time PCR. From those samples tested, 13.1 por cento (147/1124) were positive by IgM capture enzyme-linked immunosorbent assay. From these, 95 (64.6 por cento) presented only IgM and 52 (35.4 por cento) showed the presence of anti-dengue IgG. Considering the rate between IgM and IgG > 1.5 as an indicative of primary infection, from the 147 infections by the dengue virus, 102 (69 por cento) cases were characterized as primary infection and 45 (31 por cento) as secondary infection. Among the seropositive patients the proportion of females, young adults and individuals residing in Ilha do Governador was higher. The population most affected was white without predominance of a specific gender, age and location of residence. The most significant clinical manifestations observed were rash and itching and leukopenia, lymphocytosis and thrombocytopenia constituted the main hematological profile observed in the patients with dengue infection. The epidemic occurred during the hottest months of the year where elevated temperatures and high pluvial index are common. A higher seropositivity was observed in serum samples collected between the 4th and 8th day after the onset of the disease. The virus serotype virus responsible for the epidemic belongs to serotype 3 and Real time PCR demonstrated to be more sensitive than the conventional technique used to detect the infecting serotype.