Virus detection and duration of illness among patients with 2009 pandemic influenza a (H1N1) virus infection in Texas

Knowledge from early outbreaks is limited regarding the virus detection and illness duration of the 2009 pandemic influenza A (H1N1) infections. During the period from April to May 2009 in Texas, we collected serial nasopharyngeal (NP) and stool specimens from 35 participants, testing by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) and culture. The participants were aged 2 months to 71 years; 25 (71%) were under 18. The median duration of measured fever was 3.0 days and of virus detection in NP specimens was 4.2 days; however, few specimens were collected between days 5-9. The duration of virus detection (4.2 days) was similar to the duration of fever (3.5 days) (RR, 1.14; 95% CI,. 66-1.95; P=.8), but was shorter than the duration of cough (11.0 days) (RR,. 41; 95% CI,. 24-.68; P<.001). We detected viral RNA in two participants' stools. All cultures were negative. This investigation suggests that the duration of virus detection was likely similar to the seasonal influenza virus. © 2011 The Author.