An early report from newly established laboratory-based influenza surveillance in Lao PDR

Background Prior to 2007, little information was available about the burden of influenza in Laos. We report data from the first laboratory-based influenza surveillance system established in the Lao People's Democratic Republic. Methods Three hospitals in the capital city of Vientiane began surveillance for influenza-like illness (ILI) in outpatients in 2007 and expanded to include hospitalized pneumonia patients in 2008. Nasal/throat swab specimens were collected and tested for influenza and other respiratory viruses by multiplex ID-TagTM respiratory viral panel (RVP) assay on a Luminex (R) 100x MAP IS instrument (Qiagen, Singapore). Results During January 2007 to December 2008, 287 of 526 (54 center dot 6%) outpatients with ILI were positive for at least one respiratory virus. Influenza was most commonly identified, with 63 (12 center dot 0%) influenza A and 92 (17 center dot 5%) influenza B positive patients identified. In 2008, six of 79 (7 center dot 6%) hospitalized pneumonia patients were positive for influenza A and four (5 center dot 1%) were positive for influenza B. Children < 5 years represented 19% of viral infections in outpatients and 38% of pneumonia inpatients. Conclusion Our results provide the first documentation of influenza burden among patients with febrile respiratory illness and pneumonia requiring hospitalization in Laos. Implementing laboratory-based influenza surveillance requires substantial investments in infrastructure and training. However, continuing outbreaks of avian influenza A/H5N1 in poultry and emergence of the 2009 influenza A(H1N1) pandemic strain further underscore the importance of establishing and maintaining influenza surveillance in developing countries.