Avian influenza (H5N1) update: Role of the clinical microbiology laboratory

This article provides an update on the H5N1 virus and the role of the clinical microbiology laboratory in the diagnosis of H5N1 influenza. Although overshadowed recently by the influenza A H1N1 2009 pandemic, the influenza A H5N1 virus continues to circulate among avian species and cause morbidity and mortality in man. The H5N1 virus is evolving, creating the potential for a new strain that is efficiently transmitted from person to person, while remaining highly lethal. Surveillance is essential to detect the spread of, and changes in, the virus. Laboratory testing is an important element of surveillance and patient management. The clinical microbiology laboratory has a number of diagnostic tools for detecting influenza viruses, including antigen detection, serology, virus culture, and nucleic acid amplification. The relative performance characteristics of these tests vary significantly. In addition, the sensitivity of tests may differ between influenza strains, including H5N1.