Rapid-Test Sensitivity for Novel Swine-Origin Influenza A (H1N1) Virus in Humans

Abstract

The Naval Health Research Center serves as the Navy hub for the Department of Defense's Global Emerging Infections Surveillance and Response System (GEIS), in which it monitors influenza-like illness among recruit trainees of all military services, military dependents, and crew members of large Navy ships (population, >1000). The center works in collaboration with the Border Infectious Disease Surveillance Project of the Centers for Disease Control and Prevention (CDC), which monitors populations located on the border between California and Mexico. The first two human cases of novel swine-origin influenza A (H1N1) virus (S-OIV), known as swine flu, in the United States were detected through these programs.¹ In the first case, an untypeable influenza A strain was identified at a surveillance site of the Naval Health Research Center by a new diagnostic device. The test results were forwarded per protocol to the study reference laboratory for polymerase-chain-reaction (PCR) confirmation and were subsequently forwarded to the CDC for identification by sequencing. In the second case, a sample that was obtained at a border surveillance site was found to contain an untypeable influenza A strain on PCR testing at the center. Further characterization by PCR assay and electrospray ionization mass spectrometry indicated a swine-origin virus, and sequence data that were sent to the CDC revealed that the viruses in the two samples were identical. In response, surveillance activities of all programs were enhanced to include increased sampling rates, more clinical sites, decreased turnaround time in the laboratory, and rapid influenza testing with the use of QuickVue Influenza A+B (Quidel).