Prevalence and control of H7 avian influenza viruses in birds and humans

Mostafa, Ahmed; Veits, Jutta; Mettenleiter, Thomas C.

doi:10.1017/s0950268813003324

Cited by 63 publications

(59 citation statements)

References 245 publications

(350 reference statements)

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“…Except viruses of the N1 and N8 subtypes in group 1, all NA subtypes that have infected humans belong to group 2. Of note, N2, N3, N7, and N9 were first found in combination with the H7 subtype in humans and caused mild to severe conjunctive and respiratory symptoms (27,34,35). Most cases of human infection with H7N2, H7N3, and H7N7 viruses have been related to poultry exposure, with limited evidence of sustained human-to-human transmission, and nearly all patients have recovered after antiviral treatment (35).…”

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confidence: 99%

“…Of note, N2, N3, N7, and N9 were first found in combination with the H7 subtype in humans and caused mild to severe conjunctive and respiratory symptoms (27,34,35). Most cases of human infection with H7N2, H7N3, and H7N7 viruses have been related to poultry exposure, with limited evidence of sustained human-to-human transmission, and nearly all patients have recovered after antiviral treatment (35). However, H7N9 is emerging in China, with more than 70% of infected people having influenza-like illness and rapidly progressive respiratory disorders (34,36).…”

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confidence: 99%

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Unique Determinants of Neuraminidase Inhibitor Resistance among N3, N7, and N9 Avian Influenza Viruses

Song

Marathe

Kumar

et al. 2015

J Virol

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Human infections with avian influenza viruses are a serious public health concern. The neuraminidase (NA) inhibitors (NAIs) are the frontline anti-influenza drugs and are the major option for treatment of newly emerging influenza. Therefore, it is essential to identify the molecular markers of NAI resistance among specific NA subtypes of avian influenza viruses to help guide clinical management. NAI-resistant substitutions in NA subtypes other than N1 and N2 have been poorly studied. Here, we identified NA amino acid substitutions associated with NAI resistance among influenza viruses of N3, N7, and N9 subtypes which have been associated with zoonotic transmission. We applied random mutagenesis and generated recombinant influenza viruses carrying single or double NA substitution(s) with seven internal genes from A/Puerto Rico/8/1934 (H1N1) virus. In a fluorescencebased NA inhibition assay, we identified three categories of NA substitutions associated with reduced inhibition by NAIs (oseltamivir, zanamivir, and peramivir): (i) novel subtype-specific substitutions in or near the enzyme catalytic site (R152W, A246T, and D293N, N2 numbering), (ii) subtype-independent substitutions (E119G/V and/or D and R292K), and (iii) substitutions previously reported in other subtypes (Q136K, I222M, and E276D). Our data show that although some markers of resistance are present across NA subtypes, other subtype-specific markers can only be determined empirically. IMPORTANCE The number of humans infected with avian influenza viruses is increasing, raising concerns of the emergence of avian influenza viruses resistant to neuraminidase (NA) inhibitors (NAIs).Since most studies have focused on NAI-resistance in human influenza viruses, we investigated the molecular changes in NA that could confer NAI resistance in avian viruses grown in immortalized monolayer cells, especially those of the N3, N7, and N9 subtypes, which have caused human infections. We identified not only numerous NAI-resistant substitutions previously reported in other NA subtypes but also several novel changes conferring reduced susceptibility to NAIs, which are subtype specific. The findings indicate that some resistance markers are common across NA subtypes, but other markers need to be determined empirically for each subtype. The study also implies that antiviral surveillance monitoring could play a critical role in the clinical management of influenza virus infection and an essential component of pandemic preparedness.

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confidence: 99%

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confidence: 99%

Unique Determinants of Neuraminidase Inhibitor Resistance among N3, N7, and N9 Avian Influenza Viruses

Song

Marathe

Kumar

et al. 2015

J Virol

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“…Han et al [13] analyzed the relationship between Human infections with avian influenza A(H7N9) virus in Huzhou city and the exposure of live poultry, and found that there was an obvious epidemiological link between them. In addition, the closure of live poultry markets and the suspension of live poultry trading were effective measures to control the spread of the H7N9 virus in the high-incidence areas, which could significantly reduce the incidence of outbreaks [2], and the live poultry markets infected by H7N9 virus were the most likely source of the epidemic [4,6,10].…”

Section: Research Status Analysesmentioning

confidence: 99%

Research Review of Human Infections with Avian Influenza A(H7N9) Virus in China

Dong¹

2017

Advances in Computer Science Research

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Abstract. The emergence of H7N9 virus attracted worldwide concerns about the possibility of a new influenza pandemic in March 2013, and the human cases were mainly distributed in the southeast coastal areas in China, and the winter-spring season was the peak period for human infection with H7N9 virus. The studies on Human infections with avian influenza A(H7N9) virus at present are mainly divided into three categories: gene research, animal model research, outbreak simulation and risk prediction model research. The former two kinds of studies can provide lots of useful information on the mechanisms of H7N9 virus and the principles of infection, and the third kind of research can provide scientific basis and information decision-making tool for the prevention and monitoring of Human infections with avian influenza A(H7N9) virus. The impacts of environmental factors on H7N9 outbreak should be taken into account in the future study, and the closure of live poultry market as well as the suspension of live poultry trading should be vigorously pursued to control the spread of H7N9 epidemic in the high incidence areas in China.

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“…ow-pathogenic (LP) avian influenza A viruses (AIVs) of the H5 and H7 subtypes in wild avian species are unique compared to the other 14 AIV subtypes, as they can become highly pathogenic and infect both poultry and mammalian species, including humans, seals, swine, and horses (1)(2)(3)(4)(5). The first studied AIV was an H7 virus originally described by Perroncito in northern Italy in 1878 as "fowl plague" (6).…”

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confidence: 99%

“…Most human H7 influenza A virus infections have been associated with poultry contact (1). Therefore, in the event of a large-scale outbreak in poultry, increased human contact may be an important risk factor.…”

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confidence: 99%

Potential for Low-Pathogenic Avian H7 Influenza A Viruses To Replicate and Cause Disease in a Mammalian Model

Zanin

Koçer

Poulson

et al. 2017

J Virol

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H7 subtype influenza A viruses are widely distributed and have been responsible for human infections and numerous outbreaks in poultry with significant impact. Despite this, the disease-causing potential of the precursor low-pathogenic (LP) H7 viruses from the wild bird reservoir has not been investigated. Our objective was to assess the disease-causing potential of 30 LP H7 viruses isolated from wild avian species in the United States and Canada using the DBA/2J mouse model. Without prior mammalian adaptation, the majority of viruses, 27 (90%), caused mortality in mice. Of these, 17 (56.7%) caused 100% mortality and 24 were of pathogenicity similar to that of A/Anhui/1/2013 (H7N9), which is highly pathogenic in mice. Viruses of duck origin were more pathogenic than those of shorebird origin, as 13 of 18 (72.2%) duck origin viruses caused 100% mortality while 4 of 12 (33.3%) shorebird origin viruses caused 100% mortality, despite there being no difference in mean lung viral titers between the groups. Replication beyond the respiratory tract was also evident, particularly in the heart and brain. Of the 16 viruses studied for fecal shedding, 11 were detected in fecal samples. These viruses exhibited a strong preference for avian-type ␣2,3-linked sialic acids; however, binding to mammalian-type ␣2,6-linked sialic acids was also detected. These findings indicate that LP avian H7 influenza A viruses are able to infect and cause disease in mammals without prior adaptation and therefore pose a potential public health risk.IMPORTANCE Low-pathogenic (LP) avian H7 influenza A viruses are widely distributed in the avian reservoir and are the precursors of numerous outbreaks of highly pathogenic avian influenza viruses in commercial poultry farms. However, unlike highly pathogenic H7 viruses, the disease-causing potential of LP H7 viruses from the wild bird reservoir has not been investigated. To address this, we studied 30 LP avian H7 viruses isolated from wild avian species in the United States and Canada using the DBA/2J mouse model. Surprisingly, the majority of these viruses, 90%, caused mortality in mice without prior mammalian adaptation, and 56.7% caused 100% mortality. There was also evidence of spread beyond the respiratory tract and fecal shedding. Therefore, the disease-causing potential of LP avian H7 influenza A viruses in mammals may be underestimated, and these viruses therefore pose a potential public health risk.KEYWORDS H7, influenza, avian viruses, viral pathogenesis

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Prevalence and control of H7 avian influenza viruses in birds and humans

Cited by 63 publications

References 245 publications

Unique Determinants of Neuraminidase Inhibitor Resistance among N3, N7, and N9 Avian Influenza Viruses

Unique Determinants of Neuraminidase Inhibitor Resistance among N3, N7, and N9 Avian Influenza Viruses

Research Review of Human Infections with Avian Influenza A(H7N9) Virus in China

Potential for Low-Pathogenic Avian H7 Influenza A Viruses To Replicate and Cause Disease in a Mammalian Model

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