Influenza A Viruses of Swine (IAV-S) in Vietnam from 2010 to 2015: Multiple Introductions of A(H1N1)pdm09 Viruses into the Pig Population and Diversifying Genetic Constellations of Enzootic IAV-S

ABSTRACT Active surveillance of influenza A viruses of swine (IAV-S) involving 262 farms and 10 slaughterhouses in seven provinces in northern and southern Vietnam from 2010 to 2015 yielded 388 isolates from 32 farms; these viruses were classified into H1N1, H1N2, and H3N2 subtypes. Whole-genome sequencing followed by phylogenetic analysis revealed that the isolates represented 15 genotypes, according to the genetic constellation of the eight segments. All of the H1N1 viruses were entirely A(H1N1)pdm09 viruses, whereas all of the H1N2 and H3N2 viruses were reassortants among 5 distinct ancestral viruses: H1 and H3 triple-reassortant (TR) IAV-S that originated from North American pre-2009 human seasonal H1, human seasonal H3N2, and A(H1N1)pdm09 viruses. Notably, 93% of the reassortant IAV-S retained M genes that were derived from A(H1N1)pdm09, suggesting some advantage in terms of their host adaptation. Bayesian Markov chain Monte Carlo analysis revealed that multiple introductions of A(H1N1)pdm09 and TR IAV-S into the Vietnamese pig population have driven the genetic diversity of currently circulating Vietnamese IAV-S. In addition, our results indicate that a reassortant IAV-S with human-like H3 and N2 genes and an A(H1N1)pdm09 origin M gene likely caused a human case in Ho Chi Minh City in 2010. Our current findings indicate that human-to-pig transmission as well as cocirculation of different IAV-S have contributed to diversifying the gene constellations of IAV-S in Vietnam. IMPORTANCE This comprehensive genetic characterization of 388 influenza A viruses of swine (IAV-S) isolated through active surveillance of Vietnamese pig farms from 2010 through 2015 provides molecular epidemiological insight into the genetic diversification of IAV-S in Vietnam after the emergence of A(H1N1)pdm09 viruses. Multiple reassortments among A(H1N1)pdm09 viruses and enzootic IAV-S yielded 14 genotypes, 9 of which carried novel gene combinations. The reassortants that carried M genes derived from A(H1N1)pdm09 viruses became predominant, replacing those of the IAV-S that had been endemic in Vietnam since 2011. Notably, one of the novel reassortants likely caused a human case in Vietnam. Given that Vietnam is the second-largest pig-producing country in Asia, continued monitoring of IAV-S is highly important from the viewpoints of both the swine industry and human public health.

Download Full-text

An evaluation of the InDevR FluChip-8G insight microarray assay in characterizing influenza a viruses

Tropical Diseases Travel Medicine and Vaccines ◽

10.1186/s40794-021-00133-7 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Emily S. Bailey ◽

Xinye Wang ◽

Mai-juan Ma ◽

Guo-lin Wang ◽

Gregory C. Gray

Keyword(s):

Influenza A ◽

Influenza Viruses ◽

Time Range ◽

Influenza B ◽

Influenza A Viruses ◽

Laboratory Methods ◽

Duke University ◽

Multiple Viral Strains ◽

Rapid Characterization

AbstractInfluenza viruses are an important cause of disease in both humans and animals, and their detection and characterization can take weeks. In this study, we sought to compare classical virology techniques with a new rapid microarray method for the detection and characterization of a very diverse, panel of animal, environmental, and human clinical or field specimens that were molecularly positive for influenza A alone (n = 111), influenza B alone (n = 3), both viruses (n = 13), or influenza negative (n = 2) viruses. All influenza virus positive samples in this study were first subtyped by traditional laboratory methods, and later evaluated using the FluChip-8G Insight Assay (InDevR Inc. Boulder, CO) in laboratories at Duke University (USA) or at Duke Kunshan University (China). The FluChip-8G Insight multiplexed assay agreed with classical virologic techniques 59 (54.1%) of 109 influenza A-positive, 3 (100%) of the 3 influenza B-positive, 0 (0%) of 10 both influenza A- and B-positive samples, 75% of 24 environmental samples including those positive for H1, H3, H7, H9, N1, and N9 strains, and 80% of 22 avian influenza samples. It had difficulty with avian N6 types and swine H3 and N2 influenza specimens. The FluChip-8G Insight assay performed well with most human, environmental, and animal samples, but had some difficulty with samples containing multiple viral strains and with specific animal influenza strains. As classical virology methods are often iterative and can take weeks, the FluChip-8G Insight Assay rapid results (time range 8 to 12 h) offers considerable time savings. As the FluChip-8G analysis algorithm is expected to improve over time with addition of new subtypes and sample matrices, the FluChip-8G Insight Assay has considerable promise for rapid characterization of novel influenza viruses affecting humans or animals.

Download Full-text

Molecular and biological characterization of influenza A viruses isolated from human fecal samples

Infection Genetics and Evolution ◽

10.1016/j.meegid.2021.104972 ◽

2021 ◽

pp. 104972

Author(s):

Hebah A. Al Khatib ◽

Peter V. Coyle ◽

Muna A. Al Maslamani ◽

Asmaa A. Al Thani ◽

Sameer A. Pathan ◽

...

Keyword(s):

Influenza A ◽

Biological Characterization ◽

Influenza A Viruses ◽

Fecal Samples

Download Full-text

Antigenic characterization of novel H1 influenza A viruses in swine

Scientific Reports ◽

10.1038/s41598-020-61315-5 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Rodrigo Tapia ◽

Montserrat Torremorell ◽

Marie Culhane ◽

Rafael A. Medina ◽

Víctor Neira

Keyword(s):

Influenza A ◽

Influenza A Viruses ◽

Antigenic Characterization

Download Full-text

Isolation and characterization of low pathogenic H9N2 avian influenza A viruses from a healthy flock and its comparison to other H9N2 isolates

Indian Journal of Virology ◽

10.1007/s13337-013-0144-1 ◽

2013 ◽

Vol 24 (3) ◽

pp. 342-348 ◽

Cited By ~ 4

Author(s):

Muhammad Munir ◽

Siamak Zohari ◽

Muhammad Abbas ◽

Muhammad Zubair Shabbir ◽

Muhammad Nauman Zahid ◽

...

Keyword(s):

Avian Influenza ◽

Influenza A ◽

Influenza A Viruses ◽

Isolation And Characterization

Download Full-text

Swine influenza vaccines: current status and future perspectives

Animal Health Research Reviews ◽

10.1017/s146625231000006x ◽

2010 ◽

Vol 11 (1) ◽

pp. 81-96 ◽

Cited By ~ 41

Author(s):

Wenjun Ma ◽

Jürgen A. Richt

Keyword(s):

Influenza A ◽

Swine Influenza ◽

Influenza Viruses ◽

Current Status ◽

Economic Losses ◽

Influenza A Viruses ◽

Swine Industry ◽

Effective Strategies ◽

Swine Disease ◽

And Control

AbstractSwine influenza is an important contagious disease in pigs caused by influenza A viruses. Although only three subtypes of influenza A viruses, H1N1, H1N2 and H3N2, predominantly infect pigs worldwide, it is still a big challenge for vaccine manufacturers to produce efficacious vaccines for the prevention and control of swine influenza. Swine influenza viruses not only cause significant economic losses for the swine industry, but are also important zoonotic pathogens. Vaccination is still one of the most important and effective strategies to prevent and control influenza for both the animal and human population. In this review, we will discuss the current status of swine influenza worldwide as well as current and future options to control this economically important swine disease.

Download Full-text

Characterization of H9N2 influenza A viruses isolated from chicken products imported into Japan from China

Epidemiology and Infection ◽

10.1017/s0950268806006728 ◽

2006 ◽

Vol 135 (3) ◽

pp. 386-391 ◽

Cited By ~ 13

Author(s):

M. MASE ◽

M. ETO ◽

K. IMAI ◽

K. TSUKAMOTO ◽

S. YAMAGUCHI

Keyword(s):

Influenza Virus ◽

Amino Acid ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Influenza A ◽

H9n2 Virus ◽

Amino Acid Substitutions ◽

Influenza A Viruses ◽

Potential Sources

We characterized eleven H9N2 influenza A viruses isolated from chicken products imported from China. Genetically they were classified into six distinct genotypes, including five already known genotypes and one novel genotype. This suggested that such multiple genotypes of the H9N2 virus have possibly already become widespread and endemic in China. Two isolates have amino-acid substitutions that confer resistance to amantadine in the M2 region, and this supported the evidence that this mutation might be a result of the wide application of amantadine for avian influenza treatment in China. These findings emphasize the importance of surveillance for avian influenza virus in this region, and of quarantining imported chicken products as potential sources for the introduction of influenza virus.

Download Full-text

Molecular Characterization of the Hemagglutinin and Neuraminidase Genes of H5N1 Influenza A Viruses Isolated from Poultry in Vietnam from 2004 to 2005

Journal of Veterinary Medical Science ◽

10.1292/jvms.68.527 ◽

2006 ◽

Vol 68 (5) ◽

pp. 527-531 ◽

Cited By ~ 16

Author(s):

Yukiko MURAMOTO ◽

Thi Quynh Mai LE ◽

Lien Song PHUONG ◽

Tung NGUYEN ◽

Thu Ha NGUYEN ◽

...

Keyword(s):

Molecular Characterization ◽

Influenza A ◽

Influenza A Viruses ◽

H5n1 Influenza

Download Full-text

Large-Scale Sequence Analysis of M Gene of Influenza A Viruses from Different Species: Mechanisms for Emergence and Spread of Amantadine Resistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00650-09 ◽

2009 ◽

Vol 53 (10) ◽

pp. 4457-4463 ◽

Cited By ~ 64

Author(s):

Yuki Furuse ◽

Akira Suzuki ◽

Hitoshi Oshitani

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Drug Resistant ◽

Human Influenza ◽

Influenza A Viruses ◽

M Gene ◽

Drug Pressure ◽

Human Influenza Virus ◽

Selective Pressures ◽

Amantadine Resistance

ABSTRACT Influenza A virus infects many species, and amantadine is used as an antiviral agent. Recently, a substantial increase in amantadine-resistant strains has been reported, most of which have a substitution at amino acid position 31 in the M2 gene. Understanding the mechanism responsible for the emergence and spread of antiviral resistance is important for developing a treatment protocol for seasonal influenza and for deciding on a policy for antiviral stockpiling for pandemic influenza. The present study was conducted to identify the existence of drug pressure on the emergence and spread of amantadine-resistant influenza A viruses. We analyzed data on more than 5,000 virus sequences and constructed a phylogenetic tree to calculate selective pressures on sites in the M2 gene associated with amantadine resistance (positions 26, 27, 30, and 31) among different hosts. The phylogenetic tree revealed that the emergence and spread of the drug-resistant M gene in different hosts and subtypes were independent and not through reassortment. For human influenza virus, positive selection was detected only at position 27. Selective pressures on the sites were not always higher for human influenza virus than for viruses of other hosts. Additionally, selective pressure on position 31 did not increase after the introduction of amantadine. Although there is a possibility of drug pressure on human influenza virus, we could not find positive pressure on position 31. Because the recent rapid increase in drug-resistant virus is associated with the substitution at position 31, the resistance may not be related to drug use.

Download Full-text