ABSTRACT
Objective To analyze the resistance of influenza virus to neuraminidase inhibitors (NAI) in Hebei province during 2018-2019. Methods Virus were collected from the Hebei Influenza Surveillance Network during 2018-2019. A total of 36 confirmed influenza viruses (with 25 H1pdm09 and 11 H3N2) were selected to test resistance to oseltamivir and zanamivi with fluorescence (FL). Results All 36 influenza viruses tested were sensitive to oseltamivir and zanamivir. The median half maximal inhibitory concentration (IC50) for oseltamivir of H1pdm09 and H3N2 were of 0.50 nM (range 0.07-1.14 nM) and 0.25 nM (range 0.09-0.69 nM) respectively, while 0.29 nM (range 0.09-0.85 nM) and 0.87(range 0.17-1.81 nM) for zanamivir, all were within 10 fold IC50 of the reference virus (corresponding type). Conclusion All the tested influenza strains isolated in Hebei province during 2018-2019 were sensitive to NAI.
ABSTRACT
This study aimed to investigate viral infections and the prevalence of influenza-like illness (ILI) in Shijiazhuang, China, in 2011 and to provide a scientific basis for the diagnosis and control of respiratory tract infections. Throat swab specimens were collected from 483 cases of ILI who were outpatients in the influenza surveillance sentinel hospitals in Shijiazhuang between January and December 2011. All specimens were examined by multiplex RT-PCR for the following 15 respiratory tract viruses: adenovirus (ADV), human rhinovirus (HRV), human parainfluenza virus (PIV types 1-4), influenza virus A (FluA), influenza virus B (FluB), human enterovirus (HEV), respiratory syncytial virus (RSV-A and -B), human metapneumovirus (HMPV), human coronavirus (HCoV-229E/NL63 and -OC43/HKU1), and human bocavirus (HBoV). Among the 483 cases of ILI, 214 (44.31%) were positive for viruses, including ADV (8.7%), HEV (8.7%), RSV-A (8.07%), HRV (7.45%), FluA (5.38%), HCoV-OC43/ HKU1 (2.9%), PIV-3 (2.9%), HMPV (1.86%), PIV-1 (1.24%), HCoV-229E/NL63 (1.04%), PIV-2 (1.04%), HBoV (0.83%), and FluB (0.41%). Twenty-six (5.38%) of all cases were co-infected with two or more viruses, most commonly HEV/HRV with other viruses. Cases of viral infection were detected throughout the year, with peaks in January and February. ADV and HRV were detected throughout almost the whole year without obvious seasonality. HEV was detected between April and November, with a peak of prevalence in summer and autumn. FluA and FluB reached epidemic levels mainly in winter and spring. All cases of RSV were identified to be subtype A. PIV infection was mainly caused by PIV-3. The positive rate of HCoV-OC43/HKU1 infection was significantly higher than that of HCoV-229E/NL63. The leading five viruses that resulted in ILI Shijiazhuang in 2011 were HEV, ADV, RSV-A, HRV, and FluA, and these viruses have different epidemiological features.