671. Comparison of Early Clinical Presentation of Acute Dengue Versus Influenza Infection
Session: Abstracts: Virology
Friday, October 22, 2010
Background: Early dengue infection can present as an influenza-like illness. Differentiating dengue from influenza is important for clinical and public health reasons. We undertook this prospective study to compare the clinical and laboratory features of early dengue infection with influenza among adults at initial presentation to an outpatient clinic setting.

Methods: We prospectively evaluated all adult patients with acute fever onset of less than seventy-two hours duration in the outpatient setting. All patients completed a standardized questionnaire on demographics and symptomatology at presentation. Blood samples were collected for dengue polymerase chain reaction, isolation and serology. Nasal samples were analyzed for viral respiratory pathogens using direct immunofluorescence assay (DFA) and culture techniques. A monoclonal antibody respiratory screen against known respiratory pathogens were also applied to DFA positive samples.

Results: A total of 118 cases of laboratory confirmed dengue (n=35) and influenza (n=83) cases were analysed. Other than age, the demographics of both groups were similar. On univariate analysis, dengue cases were older ( 39 vs 32 years, p=0.02)  and had more vomiting (15.2% vs 3.5%, p=0.02) and rashes (15.2% vs 0%, p<0.01) at presentation. Dengue cases were also more likely to have leucopenia (3.9+/-1.4  vs 7.0+/-2.5, p<0.01 ) , lower platelet counts (165+/-78 vs 213+/-70, p<0.01) and lymphopenia (0.61 +/- 0.39  vs 0.98+/- 0.46, p<0.01 ). Dengue patients were significantly more likely to require subsequent hospitalization (OR 23;  95%CI 3, 173). On multivariate analysis, leucopenia  and lymphopenia on initial testing  were more predictive of dengue infection.

Conclusion: The early clinical features of acute dengue and influenza are very similar. Basic laboratory testing is useful in differentiating the two diseases.

Subject Category: V. Virology including clinical and basic studies of viral infections, including hepatitis

Jenny Low, MD, MPH , Infectious Diseases, Communicable Disease Centre, Tan Tock Seng Hospital, Singapore, Singapore
Adrian Ong, MD, MPH , Infectious Diseases, Communicable Disease Centre, Tan Tock Seng Hospital, Singapore, Singapore
Eng Eong Ooi, PhD , Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore, Singapore


J. Low, None

A. Ong, None

E. E. Ooi, None

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