Comparison of a New Gold Immunochromatographic Assay for the Rapid Diagnosis of the Novel Influenza A (H7N9) Virus with Cell Culture and a Real-Time Reverse-Transcription PCR Assay

Abstract

We assessed a colloidal gold immunochromatographic assay (GICA) for rapid detection of influenza A (H7N9) and compared it with reverse-transcription-polymerase chain reaction (RT-PCR) and viral culture. Samples from 35 H7N9 infected patients were collected, including 45 throat swab samples, 56 sputum samples, and 39 feces samples. All samples were tested by GICA, viral culture, and RT-PCR. GICA specifically reacted with recombinant HA proteins, virus lysates, and clinical samples from H7 subtype viruses. Compared with RT-PCR, GICA demonstrated low sensitivity (33.33%) but high specificity (97.56%). The positive rate of GICA tests for samples collected in the period from 8 to 21 days after contact with poultry was much higher than those for samples collected before or after this period. Compared with viral culture, GICA showed sensitivity of 91.67% and specificity of 82.03%. Sputum specimens were more likely to test positive for H7N9 virus than samples from throat swabs and feces. The GICA-based H7 test is a reliable, rapid, and convenient method for the screening and diagnosis of influenza A (H7N9) disease, especially for the sputum specimens with high viral load. It may be helpful in managing H7N9 epidemics and preliminary diagnosis in early stages in resource-limited settings.

Development of a Colloidal Gold-Based Immunochromatographic Strip for Rapid Detection of H7N9 Influenza Viruses

“… Manzoor et al (2008) developed a Pen-site Test Kit for the rapid diagnosis of H7 highly pathogenic avian influenza with a limit of detection of 4.5 log 10 EID 50 for detecting both swab samples and tissue homogenates, less sensitive than our strips (2.5 log 10 EID 50 ). Jin et al (2014) also developed a GICA for H7N9 AIVs from infected patients, with relatively low sensitivity (33.3%) compared with RT-PCR, and not as good as the sensitivity of our assay (85.7%). Although the rapid immunoassay was less sensitive than rRT-PCR or virus isolation, the strips could detect the clinical samples from LPMs, which could be used as an indicator for H7N9 subtype AIV infections.…”

Research progress on human infection with avian influenza H7N9

“…Nucleic acid detection of H7N9 virus is the most commonly used and convenient and rapid method of pathogen detection. Nucleic acid detection should be the first choice for suspected human infection with H7N9 avian influenza [16]. Nucleic acids in respiratory secretions should be tested regularly in all positive cases until they become negative.…”

“…H7N9 virus may mutate during isolation using chicken embryo because they are poultry cells; however, the yield of virus is high after isolation from chicken embryos. Currently, both methods are often used [16]. In addition, respiratory samples can be stored for up to one month when frozen at -80°C after the addition of virus preservative.…”

“…However, compared with the quantitative PCR method, the sensitivity of immunocolloid gold technique is poor, but its specificity is good, reaching 97.56%. Compared with virus culture method, the sensitivity and specificity of immunocolloid gold technique are better, making it useful as a rapid screening method with a certain clinical diagnostic value [16].…”

Evaluation and application of a one-step duplex real-time reverse transcription polymerase chain reaction assay for the rapid detection of influenza A (H7N9) virus from poultry samples

“…Molecular techniques for detecting influenza viruses, such as real-time reverse transcription polymerase chain reaction (rRT-PCR) and reverse transcription loop-mediated isothermal amplification (RT-LAMP), exhibit high sensitivity and specificity [13][14][15][16][17][18][19]. On April 8, 2013, the World Health Organization (WHO) Collaborating Center for Reference and Research on Influenza at the Chinese National Influenza Center provided an rRT-PCR protocol (WHO-rRT-PCR) for the detection of H7N9 viruses [20].…”