The diversity of avian influenza virus subtypes in live poultry markets before and during the second wave of A(H7N9) infections in Hangzhou, China

Li, Jun; Yu, Xinliang; Pu, Xiaoying; Yang, X. B.; Yu, Keming; Zhou, Yitong; Qian, Xin; Xie, Li; Pan, Jinren

doi:10.1038/emi.2015.14

Cited by 12 publications

(9 citation statements)

References 11 publications

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“…The potential for reassortment between AIVs, including A/H5N1, could result in the emergence of viral strains with considerable impacts on poultry and/or human health. This study, coupled with other recent studies in LBMs from other Asian countries, [15][16][17] confirms that the environment of LBMs provides a pool of genes for potential emergence of new pandemic viruses. The silent circulation of a multitude of LPAI viruses, which remain undetected and unmonitored in most Asian countries, heightens the threat when they co-circulate with pandemic candidates such as A/H5N1 and A/H7N9.…”

Section: Positivity (%)supporting

confidence: 86%

“…Avian influenza viruses (AIVs) naturally infect the gastrointestinal tracts of wild birds from the Orders Anseriformes (ducks, geese and swans) and Charadriformes (waders and gulls). Within these hosts, 16 haemagglutinin (HA) and nine neuraminidase (NA) surface glycoprotein types have been described. The HA and NA types carried by the virus are used for classification and can be found in various combinations, such as A/H5N1 and A/H3N2.…”

Section: Introductionmentioning

confidence: 99%

“…12 Previous studies have established that LBMs serve as hubs for the circulation and persistence of AIVs through the presence of multiple avian species, the constant introduction of immunologically naive hosts and the frequent lack of biosecurity measures. 1,13,14 Recent surveillance studies have documented that A/H5N1 and A/H7N9 commonly co-circulate with other subtypes of avian influenza in LBMs, [15][16][17] thus increasing the likelihood of reassortment events.…”

Section: Introductionmentioning

confidence: 99%

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Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections

Horm

Tarantola

Rith

et al. 2016

Emerging Microbes & Infections

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Surveillance for avian influenza viruses (AIVs) in poultry and environmental samples was conducted in four live-bird markets in Cambodia from January through November 2013. Through real-time RT-PCR testing, AIVs were detected in 45% of 1048 samples collected throughout the year. Detection rates ranged from 32% and 18% in duck and chicken swabs, respectively, to 75% in carcass wash water samples. Influenza A/H5N1 virus was detected in 79% of samples positive for influenza A virus and 35% of all samples collected. Sequence analysis of full-length haemagglutinin (HA) and neuraminidase (NA) genes from A/H5N1 viruses, and full-genome analysis of six representative isolates, revealed that the clade 1.1.2 reassortant virus associated with Cambodian human cases during 2013 was the only A/H5N1 virus detected during the year. However, multiplex reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of HA and NA genes revealed co-circulation of at least nine low pathogenic AIVs from HA1, HA2, HA3, HA4, HA6, HA7, HA9, HA10 and HA11 subtypes. Four repeated serological surveys were conducted throughout the year in a cohort of 125 poultry workers. Serological testing found an overall prevalence of 4.5% and 1.8% for antibodies to A/H5N1 and A/H9N2, respectively. Seroconversion rates of 3.7 and 0.9 cases per 1000 person-months participation were detected for A/H5N1 and A/H9N2, respectively. Peak AIV circulation was associated with the Lunar New Year festival. Knowledge of periods of increased circulation of avian influenza in markets should inform intervention measures such as market cleaning and closures to reduce risk of human infections and emergence of novel AIVs.

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Section: Positivity (%)supporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections

Horm

Tarantola

Rith

et al. 2016

Emerging Microbes & Infections

View full text Add to dashboard Cite

show abstract

“…Human cases have been limited to China or among travelers who visited China before returning to their home country (2). Asymptomatic H7N9 virus-infected chickens appear to be central to the persistence and expansion of this outbreak (3); accordingly, poultry contact and visitation of live poultry markets has been linked with H7N9 virus infection (4,5), and the closure of live poultry markets has been associated with a decline of new human infections in 2013 and 2014 (6,7). Limited family clusters of H7N9 virus infection have been reported (8,9), but human-tohuman transmission has remained a rarely documented and unsustainable event (10), while human infections continue to occur following exposure to H7N9 viruses circulating in avian reservoirs (11).…”

mentioning

confidence: 99%

Mammalian Pathogenesis and Transmission of H7N9 Influenza Viruses from Three Waves, 2013-2015

Belser

Creager

Sun

et al. 2016

J Virol

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Three waves of human infection with H7N9 influenza viruses have concluded to date, but only viruses within the first wave (iso-lated IMPORTANCE H7N9 influenza viruses, first isolated in 2013, continue to cause human infection and represent an ongoing public health threat.Now entering the fourth wave of human infection, H7N9 viruses continue to exhibit genetic diversity in avian hosts, necessitating continuous efforts to monitor their pandemic potential. However, viruses isolated post-2013 have not been extensively studied, limiting our understanding of potential changes in virus-host adaptation. In order to ensure that current research with firstwave H7N9 viruses still pertains to more recently isolated strains, we compared the relative virulence and transmissibility of H7N9 viruses isolated during the second and third waves, through 2015, in the mouse and ferret models. Our finding that second-and third-wave viruses generally exhibit disease in mammals comparable to that of first-wave viruses strengthens our ability to extrapolate research from the 2013 viruses to current public health efforts. These data further contribute to our understanding of molecular determinants of pathogenicity, transmissibility, and tropism.

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“…Among these, only 3 HA subtypes (H1–H3) and 2 NA subtypes (N1–N2) have been recorded in human type A influenza virus epidemics. However, the potential of other avian influenza virus (AIV) subtypes to break the species-barrier and attain transmissibility in humans also poses a grave threat to public health [8, 9]. In recent years, several AIV subtypes have acquired the ability to break species barriers and directly infect humans or other mammalian species, including the highly pathogenic H5N1 avian influenza viruses (HPAIV), H7N7, H9N2, H6N1, H10N8, and H7N9 AIVs [10–15].…”

Section: Introductionmentioning

confidence: 99%

Blockage of regulatory T cells augments induction of protective immune responses by influenza virus-like particles in aged mice

Wen

Wang

Dong

et al. 2017

Microbes and Infection

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Elderly humans over 65 years old are at great risk to pathogenesis by influenza virus infection. However, although influenza vaccines provide effective protection in healthy young adults, protection of elderly adults is substantially lower even with a good match between the vaccine and the circulating influenza virus. To gain insight of the underlying mechanism for the reduced immunogenicity of influenza vaccines in the aged population, we investigated immunogenicity of influenza virus-like particle vaccines in aged mice, which represent a useful model for studying aging associated impairment in immune responses. Specifically, we investigated the effect of inhibiting regulatory T cells in aged mice on induction of protective immune responses by influenza vaccines. Our results showed that injecting anti-CD25 antibodies could down-regulate CD25 on the surface of regulatory T cells and significantly increase the levels of antibody responses induced by VLP immunization in aged mice. Further, the profiles of antibody responses were also changed towards Th1 type by regulatory T cell blockage in aged mice. Moreover, aged mice that were treated by anti-CD25 antibodies prior to vaccination were more effectively protected against lethal influenza virus challenge.

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The diversity of avian influenza virus subtypes in live poultry markets before and during the second wave of A(H7N9) infections in Hangzhou, China

Cited by 12 publications

References 11 publications

Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections

Intense circulation of A/H5N1 and other avian influenza viruses in Cambodian live-bird markets with serological evidence of sub-clinical human infections

Mammalian Pathogenesis and Transmission of H7N9 Influenza Viruses from Three Waves, 2013-2015

Blockage of regulatory T cells augments induction of protective immune responses by influenza virus-like particles in aged mice

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