Xiuming Peng

Multiple amino acid substitutions involved in the adaptation of avian-origin influenza A (H10N7) virus in mice.

AbstractTo identify substitutions nthat are possibly associated with the adaptation of avian-origin H10N7 virus to mammals, adaptation of the H10N7 virus in mouse lung was carried out by serial lung-to-lung passage. Genomic analysis of the mouse-adapted virus revealed amino acid changes in the PB2 (E627K), PA (T97I), and HA (G409E) proteins, and this virus was more virulent in mice than the wild-type virus. Our results suggest that these substitutions are involved in the enhancement of the replication efficiency of avian-origin H10N7 virus, resulting in severe disease in mice. Continued poultry surveillance of these substitutions in H10N7 viruses is required.

Amino acid substitutions occurring during adaptation of an emergent H5N6 avian influenza virus to mammals.

Avian influenza viruses (AIVs) are known to cross species barriers, and emergent highly pathogenic H5N6 AIVs pose a serious threat to human health and the poultry industry. Here, we serially passaged an H5N6 virus 10 times in BALB/c mice. The pathogenicity of the wild-type 6D2 (WT-6D2) and mammal-adapted 6D2 strain (MA-6D2) were compared. The viral titer in multiple organs and the death rate for MA-6D2 were significantly higher than for WT-6D2. We provide evidence that the mutations HA A150V, NA R143K and G147E, PB2 E627K, and PA A343T may be important for adaptation of H5N6 AIVs to mammals.

Amino acid substitutions involved in the adaptation of a novel highly pathogenic H5N2 avian influenza virus in mice.

BackgroundH5N2 avian influenza viruses (AIVs) can infect individuals that are in frequent contact with infected birds. In 2013, we isolated a novel reassortant highly pathogenic H5N2 AIV strain [A/duck/Zhejiang/6DK19/2013(H5N2) (6DK19)] from a duck in Eastern China. This study was undertaken to understand the adaptive processes that led enhanced replication and increased virulence of 6DK19 in mammals. 6DK19 was adapted to mice using serial lung-to-lung passages (10 passages total). The virulence of the wild-type virus (WT-6DK19) and mouse-adapted virus (MA-6DK19) was determined in mice. The whole-genome sequences of MA-6DK19 and WT-6DK19 were compared to determine amino acid differences.FindingsAmino acid changes were identified in the MA-DK19 PB2 (E627K), PB1 (I181T), HA (A150S), NS1 (seven amino acid extension “WRNKVAD” at the C-terminal), and NS2 (E69G) proteins. Survival and histology analyses demonstrated that MA-6DK19 was more virulent in mice than WT-6DK19.ConclusionOur results suggest that these substitutions are involved in the enhanced replication efficiency and virulence of H5N2 AIVs in mammals. Continuing surveillance for H5N2 viruses in poultry that are carrying these mutations is required.

Characterization of Novel Reassortant Influenza A (H5N2) Viruses Isolated from Poultry in Eastern China, 2015

Recently, novel variants of H5 highly pathogenic avian influenza viruses (AIVs) have been frequently isolated from poultry and wild birds in Asia, Europe and North America. Live poultry markets (LPMs) play an important role in the dissemination of influenza viruses. Four H5N2 AIVs were isolated from poultry during surveillance of AIVs in LPMs in Eastern China, in 2015. Whole-genome sequencing, combined with phylogenetic and antigenic analyses were performed to characterize these viruses. These H5N2 viruses had undergone extensive reassortment resulting in two genetic groups of viruses in poultry. These viruses exhibited slightly pathogenicity in mice, and replicated without prior adaptation. The continued circulation of these novel H5N2 viruses may represent a threat to human health.

Successful treatment of avian-origin influenza A (H7N9) infection using convalescent plasma

In January 2015, there was an outbreak of avian-origin influenza A (H7N9) virus in Zhejiang Province, China. A 45-year-old man was admitted to the First Affiliated Hospital of Zhejiang University with a high fever that had lasted 7 days, chills, and a cough with yellow sputum. Laboratory testing confirmed infection with the H7N9 virus, likely obtained from contact with poultry at a local live poultry market. A large dense shadow was apparent in the patients left lung at the time of admission. Treatment with oseltamivir (75mg twice daily) did not improve the patients condition. The decision was made to try using convalescent plasma to treat the infection. Convalescent plasma was administered 3 days after the patient was admitted to the hospital and led to a marked improvement. To our knowledge, this is the first report of the successful use of convalescent plasma to treat a case of H7N9 infection in China. These results suggest that the combination of convalescent plasma and antiviral drugs may be effective for the treatment of avian-origin H7N9 infection.

Virulence of an H5N8 highly pathogenic avian influenza is enhanced by the amino acid substitutions PB2 E627K and HA A149V

A novel reassortant H5N8 highly pathogenic avian influenza (HPAI) virus was recently identified in Asia, Europe, and North America. The H5N8 HPAI virus has raised serious concerns regarding the potential risk for human infection. However, the molecular changes responsible for allowing mammalian infection in H5N8 HPAI viruses are not clear. The objective of this study was to identify amino acid substitutions that are potentially associated with the adaptation of H5N8 HPAI viruses to mammals. In this study, an avian-origin H5N8 virus was adapted to mice through serial lung-to-lung passage. The virulence of mouse-adapted virus was increased and adaptive mutations, HA (A149V) and PB2 (E627K), were detected after the ninth passage in each series of mice. Reverse genetics were used to generate reassortants of the wild type and mouse-adapted viruses. Substitutions in the HA (A149V) and PB2 (E627K) proteins led to enhanced viral virulence in mice, the viruses displayed expanded tissue tropism, and increased replication kinetics in mammalian cells. Continued surveillance in poultry for amino acid changes that might indicate H5N8 HPAI viruses pose a threat to human health is required.

Molecular characterization of a novel reassortant H7N6 subtype avian influenza virus from poultry in Eastern China, in 2016.

During the surveillance for avian influenza viruses (AIVs) in live poultry markets in Eastern China, in 2016, a novel reassortant H7N6 AIV was isolated from a chicken. Phylogenetic analysis showed that this strain received its genes from H9N2, H7N9 and H5N6 AIVs infecting poultry in China. This strain showed moderate pathogenicity in mice and was able to replicate in mice without prior adaptation. Considering that this novel reassorted H7N6 virus was isolated from poultry in this study, it is possible that chickens play an important role in the generation of novel reassorted H7N6 AIVs.

Establishment of a multiplex real-time RT-PCR assay for rapid identification of H6 subtype avian influenza viruses

The H6 subtype avian influenza viruses (AIVs) possess the capacity for zoonotic transmission from avian species to humans. Establishment of a specific, rapid and sensitive method to screen H6 AIVs is necessary. Based on the conserved domain of thexa0matrix and H6 AIV hemagglutininxa0genes, two TaqMan minor-groove-binder probes and multiplex real-time RT-PCR primers were designed in this study. The multiplex real-time RT-PCR assay developed in this study had high specificity and repeatability and a detection limit of 30 copies per reaction. This rapid diagnostic method will be useful for clinical detection and surveillance of H6 AIVs in China.

The tradition algorithm approach underestimates the prevalence of serodiagnosis of syphilis in HIV-infected individuals

Currently, there are three algorithms for screening of syphilis: traditional algorithm, reverse algorithm and European Centre for Disease Prevention and Control (ECDC) algorithm. To date, there is not a generally recognized diagnostic algorithm. When syphilis meets HIV, the situation is even more complex. To evaluate their screening performance and impact on the seroprevalence of syphilis in HIV-infected individuals, we conducted a cross-sectional study included 865 serum samples from HIV-infected patients in a tertiary hospital. Every sample (one per patient) was tested with toluidine red unheated serum test (TRUST), T. pallidum particle agglutination assay (TPPA), and Treponema pallidum enzyme immunoassay (TP-EIA) according to the manufacturer’s instructions. The results of syphilis serological testing were interpreted following different algorithms respectively. We directly compared the traditional syphilis screening algorithm with the reverse syphilis screening algorithm in this unique population. The reverse algorithm achieved remarkable higher seroprevalence of syphilis than the traditional algorithm (24.9% vs. 14.2%, p < 0.0001). Compared to the reverse algorithm, the traditional algorithm also had a missed serodiagnosis rate of 42.8%. The total percentages of agreement and corresponding kappa values of tradition and ECDC algorithm compared with those of reverse algorithm were as follows: 89.4%,0.668; 99.8%, 0.994. There was a very good strength of agreement between the reverse and the ECDC algorithm. Our results supported the reverse (or ECDC) algorithm in screening of syphilis in HIV-infected populations. In addition, our study demonstrated that screening of HIV-populations using different algorithms may result in a statistically different seroprevalence of syphilis.

Characterization of reassortant H1-subtype avian influenza viruses isolated from poultry in Zhejiang Province in China from 2013 to 2015

From 2013 to 2015, 32 H1-subtype avian influenza viruses (AIVs), H1N2 (nxa0=xa012), H1N3 (nxa0=xa014), H1N4 (nxa0=xa04) and H1N9 (nxa0=xa02), were isolated from poultry in Zhejiang Province in eastern China. These strains were characterized by whole-genome sequencing with subsequent phylogenetic analysis and genetic comparison. Phylogenetic analysis of all eight viral genes showed that these strains clustered in the AIV Eurasian lineage. These strains were found to be minimally pathogenic in mice and were able to replicate in mice without prior adaptation. Continued surveillance is needed, considering the important role of poultry in AIV reassortment.