A nationally coordinated laboratory system for human avian influenza a (H5N1) in Thailand: program design, analysis, and evaluation

Background. The first phase of national surveillance for avian influenza (H5N1) human disease in Thailand occurred over a 4- month period that began on 1 December 2003. Subsequently, a nationally coordinated laboratory system (NCLS) for avian influenza (H5N1) was created to assess population- based surveillance, specimen procurement, case detection, and reporting at the national level. Methods. We conducted a pre- and postintervention study to evaluate the NCLS designed during the 6- week interval from 1 April through 15 May 2004. During the pre- NCLS period (1 December 2003 through 31 March 2004), 12 cases of human avian influenza (H5N1) were confirmed. During the post- NCLS period (16 May 2004 through 31 December 2006), interventions were implemented for human avian influenza (H5N1) surveillance, case detection, and expedited, computer- based reporting. Results. During the pre- and post- NCLS periods, 777 (85%) of 915 and 10,434 (95%) of 11,042 clinical respiratory specimens, respectively, were adequate for confirmatory testing (P <.001), the median time from procurement to results decreased from 17 days (range, 14 - 24 days) to 1.8 days (range, 0.25 - 4 days;procurement to results decreased from 17 days (range, 14 - 24 days) to 1.8 days (range, 0.25 - 4 days;), and P <.001), and the duration of specimen shipment decreased from 46.5 h to 21.1 h (P<.001). Thirteen cases of avian influenza (H5N1) were detected during the 31- month postintervention period. H5N1 reverse- transcriptase polymerase chain reaction and real- time reverse- transcriptase polymerase chain reaction sensitivity was 100% and specificity was 99.8%. Conclusions. The NCLS exemplifies a systematic approach to national surveillance for avian influenza A (H5N1). This NCLS program in Thailand serves as a model for human avian influenza (H5N1) preparedness that can be adopted or modified for use in other countries.