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PLoS ONE. Clinical and Virological Factors Associated with Viremia in Pandemic Influenza A/H1N1/2009 Virus Infection
[Source: PLoS ONE, full text: (LINK). Abstract, edited.]
Clinical and Virological Factors Associated with Viremia in Pandemic Influenza A/H1N1/2009 Virus Infection
by Herman Tse, Kelvin K. W. To, Xi Wen, Honglin Chen, Kwok-**** Chan, Hoi-Wah Tsoi, Iris W. S. Li, Kwok-Yung Yuen
Background
Positive detection of viral RNA in blood and other non-respiratory specimens occurs in severe human influenza A/H5N1 viral infection but is not known to occur commonly in seasonal human influenza infection. Recently, viral RNA was detected in the blood of patients suffering from severe pandemic influenza A/H1N1/2009 viral infection, although the significance of viremia had not been previously studied. Our study aims to explore the clinical and virological factors associated with pandemic influenza A/H1N1/2009 viremia and to determine its clinical significance.
Methodology/Principal Findings
Clinical data of patients admitted to hospitals in Hong Kong between May 2009 and April 2010 and tested positive for pandemic influenza A/H1N1/2009 was collected. Viral RNA was detected by reverse-transcription polymerase chain reactions (RT-PCR) targeting the matrix (M) and HA genes of pandemic influenza A/H1N1/2009 virus from the following specimens: nasopharyngeal aspirate (NPA), endotracheal aspirate (ETA), blood, stool and rectal swab. Stool and/ or rectal swab was obtained only if the patient complained of any gastrointestinal symptoms. A total of 139 patients were included in the study, with viral RNA being detected in the blood of 14 patients by RT-PCR. The occurrence of viremia was strongly associated with a severe clinical presentation and a higher mortality rate, although the latter association was not statistically significant. D222G/N quasispecies were observed in 90% of the blood samples.
Conclusion
Presence of pandemic influenza A/H1N1/2009 viremia is an indicator of disease severity and strongly associated with D222G/N mutation in the viral hemagglutinin protein.
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by Herman Tse, Kelvin K. W. To, Xi Wen, Honglin Chen, Kwok-**** Chan, Hoi-Wah Tsoi, Iris W. S. Li, Kwok-Yung Yuen
Background
Positive detection of viral RNA in blood and other non-respiratory specimens occurs in severe human influenza A/H5N1 viral infection but is not known to occur commonly in seasonal human influenza infection. Recently, viral RNA was detected in the blood of patients suffering from severe pandemic influenza A/H1N1/2009 viral infection, although the significance of viremia had not been previously studied. Our study aims to explore the clinical and virological factors associated with pandemic influenza A/H1N1/2009 viremia and to determine its clinical significance.
Methodology/Principal Findings
Clinical data of patients admitted to hospitals in Hong Kong between May 2009 and April 2010 and tested positive for pandemic influenza A/H1N1/2009 was collected. Viral RNA was detected by reverse-transcription polymerase chain reactions (RT-PCR) targeting the matrix (M) and HA genes of pandemic influenza A/H1N1/2009 virus from the following specimens: nasopharyngeal aspirate (NPA), endotracheal aspirate (ETA), blood, stool and rectal swab. Stool and/ or rectal swab was obtained only if the patient complained of any gastrointestinal symptoms. A total of 139 patients were included in the study, with viral RNA being detected in the blood of 14 patients by RT-PCR. The occurrence of viremia was strongly associated with a severe clinical presentation and a higher mortality rate, although the latter association was not statistically significant. D222G/N quasispecies were observed in 90% of the blood samples.
Conclusion
Presence of pandemic influenza A/H1N1/2009 viremia is an indicator of disease severity and strongly associated with D222G/N mutation in the viral hemagglutinin protein.