ABSTRACT
Background: The diagnosis of acute respiratory illness caused by Hantavirus is based in the rapid and progressive clinical course, epidemiological background and the serological confirmation of the virus. When the presence of the virus is not confirmed a differential diagnosis must be made with other infections. Between 1999 and 2001, the Chilean Public Health Institute received 1063 blood samples from patients with a suspicious clinical picture, to study the presence of Andes strain of Hantavirus. In 134 of these samples, the presence of the virus was confirmed. Aim: To study the presence of other infections in sera from patients with suspected Hantavirus acute respiratory illness but serologically negative for Hantavirus. Material and methods: A retrospective study of 98 serum samples, received at the National Public Health Institute, of patients with negative serology for Hantavirus. The presence of antibodies against influenza virus, Mycoplasma pneumoniae, Leptospira and Streptococcus pneumoniae was determined using Latex techniques. Results: Leptospira was detected in 23 patients, influenza virus in 13, Streptococcus pneumoniae in six and Mycoplasma pneumoniae in one case. Leptospira infections were confirmed in four cases by ELISA determination of IgM antibodies. Influenza virus infection was confirmed in three cases by Hemmaglutation Inhibition Assay. Conclusions: In suspected cases of Hantavirus acute respiratory infection, but with negative serology, other infectious agents such as Leptospira, influenza virus and Streptococcus pneumoniae, must be sought.