scholarly journals An epidemiological study of influenza viruses among Chinese farm families with household ducks and pigs

1996 ◽  
Vol 117 (1) ◽  
pp. 179-188 ◽  
Author(s):  
L. L. Shu ◽  
N. N. Zhou ◽  
G. B. Sharp ◽  
S. Q. He ◽  
T. J. Zhang ◽  
...  
Keyword(s):  
Southern China ◽  
Seasonal Pattern ◽  
Family Members ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Farm Families ◽  
Serum Samples ◽  
Avian Viruses ◽  
Tract Infections ◽  
Human Viruses

SummaryTo examine the possibility of interspecies transmission and genetic reassortment of influenza viruses on farms in Southern China, we surveyed 20 farm families living outside the city of Nanchang who raised pigs and ducks in their homes. Weekly interviews of family members and virus isolation studies of throat swabs and faecal samples, collected from September 1992 to September 1993, established the seasonal pattern of respiratory tract infections in these families and identified 11 influenza viruses (6 in humans and 5 in ducks). Most of the human isolates were type A of H3N2 subtype. Serologic studies of farm pigs indicated infection by the same human viruses circulating in family members, but there was no evidence that either swine or avian viruses had been transmitted to pigs. Eight of 156 human serum samples inhibited the neuraminidase activity of two of the duck isolates, raising the possibility of interspecies transmission of these avian viruses. Genotype analysis of duck and human isolates provided no evidence for reassortment. Our findings support the concept that intermingling of humans, pigs and ducks on Chinese farms is favourable to the generation of new, potentially hazardous strains of influenza virus.

scholarly journals Eco-Epidemiological Evidence of the Transmission of Avian and Human Influenza A Viruses in Wild Pigs in Campeche, Mexico

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 528
Author(s):  
Brenda Aline Maya-Badillo ◽  
Rafael Ojeda-Flores ◽  
Andrea Chaves ◽  
Saul Reveles-Félix ◽  
Guillermo Orta-Pineda ◽  
...  
Keyword(s):  
Influenza A ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Serum Samples ◽  
Fragmented Habitats ◽  
Wild Pigs ◽  
Wide Range ◽  
Influenza Transmission ◽  
Human Viruses ◽  
Positive Results

Influenza, a zoonosis caused by various influenza A virus subtypes, affects a wide range of species, including humans. Pig cells express both sialyl-α-2,3-Gal and sialyl-α-2,6-Gal receptors, which make them susceptible to infection by avian and human viruses, respectively. To date, it is not known whether wild pigs in Mexico are affected by influenza virus subtypes, nor whether this would make them a potential risk of influenza transmission to humans. In this work, 61 hogs from two municipalities in Campeche, Mexico, were sampled. Hemagglutination inhibition assays were performed in 61 serum samples, and positive results were found for human H1N1 (11.47%), swine H1N1 (8.19%), and avian H5N2 (1.63%) virus variants. qRT-PCR assays were performed on the nasal swab, tracheal, and lung samples, and 19.67% of all hogs were positive to these assays. An avian H5N2 virus, first reported in 1994, was identified by sequencing. Our results demonstrate that wild pigs are participating in the exposure, transmission, maintenance, and possible diversification of influenza viruses in fragmented habitats, highlighting the synanthropic behavior of this species, which has been poorly studied in Mexico.

scholarly journals Infectivity and Transmissibility of Avian H9N2 Influenza Viruses in Pigs

2016 ◽  
Vol 90 (7) ◽  
pp. 3506-3514 ◽  
Author(s):  
Jia Wang ◽  
Maocai Wu ◽  
Wenshan Hong ◽  
Xiaohui Fan ◽  
Rirong Chen ◽  
...  
Keyword(s):  
Southern China ◽  
Influenza Pandemic ◽  
Influenza Viruses ◽  
Productive Infection ◽  
Interspecies Transmission ◽  
Influenza Surveillance ◽  
Pandemic Preparedness ◽  
Pandemic Threat ◽  
Asymptomatic Infections ◽  
Experimental Pigs

ABSTRACTThe H9N2 influenza viruses that are enzootic in terrestrial poultry in China pose a persistent pandemic threat to humans. To investigate whether the continuous circulation and adaptation of these viruses in terrestrial poultry increased their infectivity to pigs, we conducted a serological survey in pig herds with H9N2 viruses selected from the aquatic avian gene pool (Y439 lineage) and the enzootic terrestrial poultry viruses (G1 and Y280 lineages). We also compared the infectivity and transmissibility of these viruses in pigs. It was found that more than 15% of the pigs sampled from 2010 to 2012 in southern China were seropositive to either G1 or Y280 lineage viruses, but none of the sera were positive to the H9 viruses from the Y439 lineage. Viruses of the G1 and Y280 lineages were able to infect experimental pigs, with detectable nasal shedding of the viruses and seroconversion, whereas viruses of the Y439 lineage did not cause a productive infection in pigs. Thus, adaptation and prevalence in terrestrial poultry could lead to interspecies transmission of H9N2 viruses from birds to pigs. Although H9N2 viruses do not appear to be continuously transmissible among pigs, repeated introductions of H9 viruses to pigs naturally increase the risk of generating mammalian-adapted or reassorted variants that are potentially infectious to humans. This study highlights the importance of monitoring the activity of H9N2 viruses in terrestrial poultry and pigs.IMPORTANCEH9N2 subtype of influenza viruses has repeatedly been introduced into mammalian hosts, including humans and pigs, so awareness of their activity and evolution is important for influenza pandemic preparedness. However, since H9N2 viruses usually cause mild or even asymptomatic infections in mammalian hosts, they may be overlooked in influenza surveillance. Here, we found that the H9N2 viruses established in terrestrial poultry had higher infectivity in pigs than those from aquatic birds, which suggests that adaptation of the H9N2 viruses in terrestrial poultry might have increased the infectivity of the virus to mammals. Therefore, monitoring the prevalence and evolution of H9 viruses prevalent in terrestrial birds and conducting risk assessment of their threat to mammals are critical for evaluating the pandemic potential of this virus.

scholarly journals The Genesis and Evolution of H9N2 Influenza Viruses in Poultry from Southern China, 2000 to 2005

2007 ◽  
Vol 81 (19) ◽  
pp. 10389-10401 ◽  
Author(s):  
K. M. Xu ◽  
G. J. D. Smith ◽  
J. Bahl ◽  
L. Duan ◽  
H. Tai ◽  
...  
Keyword(s):  
Southern China ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Asian Countries ◽  
Domestic Ducks ◽  
H5n1 Influenza ◽  
Different Types ◽  
Multiple Virus ◽  
Great Genetic Diversity

ABSTRACT H9N2 influenza viruses have become established in terrestrial poultry in different Asian countries over the last 2 decades. Our previous study demonstrated that quail harbor increasingly diverse novel H9N2 reassortants, including both Chicken/Beijing/1/94 (Ck/Bei-like) and Quail/Hong Kong/G1/97 (G1-like) viruses. However, since 1999, the genesis and evolution of H9N2 viruses in different types of poultry have not been investigated systematically. In the present study, H9N2 viruses isolated from chickens, ducks, and other minor poultry species were characterized genetically and antigenically. Our findings demonstrate that Ck/Bei-like H9N2 viruses have been introduced into many different types of poultry in southern China, including quail, partridges, chukar, pheasant, guinea fowl, and domestic ducks, while G1-like viruses were commonly detected in quail, less frequently detected in other minor poultry species, and not detected in chickens and ducks. Genetic analysis revealed 35 genotypes of H9N2 viruses, including 14 novel genotypes that have not been recognized before. Our results also suggested that two-way interspecies transmission exists between different types of poultry. Our study demonstrates that the long-term cocirculation of multiple virus lineages (e.g., H5N1 and H9N2 viruses) in different types of poultry has facilitated the frequent reassortment events that are mostly responsible for the current great genetic diversity in H9N2 and H5N1 influenza viruses in this region. This situation favors the emergence of influenza viruses with pandemic potential.

scholarly journals Antiviral Susceptibility of Avian and Swine Influenza Virus of the N1 Neuraminidase Subtype

2010 ◽  
Vol 84 (19) ◽  
pp. 9800-9809 ◽  
Author(s):  
Terri D. Stoner ◽  
Scott Krauss ◽  
Rebecca M. DuBois ◽  
Nicholas J. Negovetich ◽  
David E. Stallknecht ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Active Site ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Oseltamivir Resistance ◽  
Naturally Occurring ◽  
Potential Source ◽  
Avian Viruses ◽  
Human Viruses

ABSTRACT Influenza viruses of the N1 neuraminidase (NA) subtype affecting both animals and humans caused the 2009 pandemic. Anti-influenza virus NA inhibitors are crucial early in a pandemic, when specific influenza vaccines are unavailable. Thus, it is urgent to confirm the antiviral susceptibility of the avian viruses, a potential source of a pandemic virus. We evaluated the NA inhibitor susceptibilities of viruses of the N1 subtype isolated from wild waterbirds, swine, and humans. Most avian viruses were highly or moderately susceptible to oseltamivir (50% inhibitory concentration [IC50], <5.1 to 50 nM). Of 91 avian isolates, 7 (7.7%) had reduced susceptibility (IC50, >50 nM) but were sensitive to the NA inhibitors zanamivir and peramivir. Oseltamivir susceptibility ranged more widely among the waterbird viruses (IC50, 0.5 to 154.43 nM) than among swine and human viruses (IC50, 0.33 to 2.56 nM). Swine viruses were sensitive to oseltamivir, compared to human seasonal H1N1 isolated before 2007 (mean IC50, 1.4 nM). Avian viruses from 2007 to 2008 were sensitive to oseltamivir, in contrast to the emergence of resistant H1N1 in humans. Susceptibility remained high to moderate over time among influenza viruses. Sequence analysis of the outliers did not detect molecular markers of drug-resistance (e.g., H275Y NA mutation [N1 numbering]) but revealed mutations outside the NA active site. In particular, V267I, N307D, and V321I residue changes were found, and structural analyses suggest that these mutations distort hydrophobic pockets and affect residues in the NA active site. We determined that natural oseltamivir resistance among swine and wild waterbirds is rare. Minor naturally occurring variants in NA can affect antiviral susceptibility.

scholarly journals Complete Genome Sequence of an Avian-Origin H3N2 Canine Influenza A Virus Isolated in Farmed Dogs in Southern China

2012 ◽  
Vol 86 (18) ◽  
pp. 10238-10238 ◽  
Author(s):  
Shuo Su ◽  
Nan Cao ◽  
Jidang Chen ◽  
Furong Zhao ◽  
Huatao Li ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Genomic Sequence ◽  
Southern China ◽  
Phylogenetic Analyses ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Avian Origin ◽  
Canine Influenza ◽  
Canine Influenza A Virus

We report here the complete genomic sequence of an avian-origin H3N2 canine influenza A virus containing multiple mutations in farmed dogs in southern China. Phylogenetic analyses of the sequences of all eight viral RNA segments demonstrated that these are wholly avian influenza viruses of the Asia lineage. To our knowledge, this is the first report of interspecies transmission of an avian H3N2 influenza virus to domestic farm dogs under natural conditions in Southern China. The amino acid information provided herein suggests that continued study is required to determine if this virus could be established in the farm dog population and pose potential threats to public health.

scholarly journals Infection of a child in Hong Kong by an influenza A H3N2 virus closely related to viruses circulating in European pigs

2001 ◽  
Vol 82 (6) ◽  
pp. 1397-1406 ◽  
Author(s):  
V. Gregory ◽  
W. Lim ◽  
K. Cameron ◽  
M. Bennett ◽  
S. Marozin ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Hong Kong ◽  
Influenza A ◽  
Southern China ◽  
Influenza Viruses ◽  
H3n2 Virus ◽  
Human Influenza ◽  
Genetic Characteristics ◽  
Source Of Infection ◽  
Human Viruses

Influenza virus A/Hong Kong/1774/99, isolated from a young child with mild influenza, was shown to be similar in its antigenic and genetic characteristics to H3N2 viruses circulating in pigs in Europe during the 1990s and in particular to be closely related to viruses isolated from two children in the Netherlands in 1993. Similar viruses had previously not been identified outside Europe. Although there is little evidence as to how the child contracted the infection, it appears likely that pigs in southern China were the source of infection. Characteristics shared with the European swine viruses include resistance to the anti-influenza drugs amantadine and rimantadine. Thus not only does this incident once again highlight the potential of pigs as a source of novel human influenza viruses, but also indicates the potential for emergence of amantadine-resistant human viruses.

scholarly journals Residue 627 of PB2 Is a Determinant of Cold Sensitivity in RNA Replication of Avian Influenza Viruses

2001 ◽  
Vol 75 (11) ◽  
pp. 5398-5404 ◽  
Author(s):  
Pascale Massin ◽  
Sylvie van der Werf ◽  
Nadia Naffakh
Keyword(s):  
Mammalian Cells ◽  
Influenza A ◽  
Cultured Cells ◽  
Rna Replication ◽  
Influenza Viruses ◽  
Cold Sensitivity ◽  
Upper Respiratory Tract ◽  
Avian Viruses ◽  
Human Viruses

ABSTRACT Human influenza A viruses replicate in the upper respiratory tract at a temperature of about 33°C, whereas avian viruses replicate in the intestinal tract at a temperature close to 41°C. In the present study, we analyzed the influence of low temperature (33°C) on RNA replication of avian and human viruses in cultured cells. The kinetics of replication of the NP segment were similar at 33 and 37°C for the human A/Puerto-Rico/8/34 and A/Sydney/5/97 viruses, whereas replication was delayed at 33°C compared to 37°C for the avian A/FPV/Rostock/34 and A/Mallard/NY/6750/78 viruses. Making use of a genetic system for the in vivo reconstitution of functional ribonucleoproteins, we observed that the polymerase complexes derived from avian viruses but not human viruses exhibited cold sensitivity in mammalian cells, which was determined mostly by residue 627 of PB2. Our results suggest that a reduced ability of the polymerase complex of avian viruses to ensure replication of the viral genome at 33°C could contribute to their inability to grow efficiently in humans.

scholarly journals Influenza in birds, pigs and humans: how strong is the species barrier?

2017 ◽  
Vol 58 (3) ◽  
pp. 208 ◽  
Author(s):  
K. Van REETH ◽  
A. De VLEESCHAUWER ◽  
C. S. KYRIAKIS
Keyword(s):  
Avian Influenza ◽  
Host Species ◽  
Experimental Studies ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Species Barrier ◽  
New Host ◽  
Highly Pathogenic ◽  
Avian Viruses ◽  
New Host Species

The recent epizootics of the highly pathogenic H5N1 avian influenza in poultry and the occasional infections of humans and other mammals, including pigs and felines, have alerted the international scientific community. New questions over the interspecies transmission of influenza viruses have been raised and the role of the pig as a "mixing vessel" of avian and human viruses has been criticized. The major aim of this review is to evaluate the zoonotic potential of avian and swine influenza. Interspecies transmissions of influenza viruses are rare virus-evolution events and very few viruses have succeeded to become established in new host species. Until the appearance of the H5N1 virus in 1996 only 3 cases of humans infected with avian viruses were recorded. The lack of human-to-human transmission of H5N1 demonstrates that extensive changes in the virus genome are required in order to overcome the species barrier. Although avian influenza viruses have been isolated from pigs, only in one occasion an avian H I N I virus transmitted from wild ducks to pigs was able to further spread in the swine population. The susceptibility of swine to highly and low pathogenic avian viruses has been confirmed in experimental studies, but pig-to-pig transmission has not been demonstrated. Experimental and natural transmission of highly pathogenic avian viruses to felines, mice, ferrets and maqacues are also discussed, showing the major differences in the virus pathogenesis among different mammalian species. The study of this pathogenesis may offer insights to the reasons of limited virus spread within a new host. We may conclude that, contrary to common believes, the species barrier remains a serious obstacle for the spread of novel influenza viruses in new host species, including humans. Our experience with H5N1 and H7N7 has tested old established theories, proving them insufficient. Further study of the factors which influence and limit the transmission of influenza viruses from one species to another is needed to better understand and evaluate the risk of the emergence of new pandemic influenza viruses.

scholarly journals Early Alterations of the Receptor-Binding Properties of H1, H2, and H3 Avian Influenza Virus Hemagglutinins after Their Introduction into Mammals

2000 ◽  
Vol 74 (18) ◽  
pp. 8502-8512 ◽  
Author(s):  
Mikhail Matrosovich ◽  
Alexander Tuzikov ◽  
Nikolai Bovin ◽  
Alexandra Gambaryan ◽  
Alexander Klimov ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Receptor Binding ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Amino Acid Substitutions ◽  
Single Mutation ◽  
Binding Properties ◽  
Avian Virus ◽  
Human Viruses

ABSTRACT Interspecies transmission of influenza A viruses circulating in wild aquatic birds occasionally results in influenza outbreaks in mammals, including humans. To identify early changes in the receptor binding properties of the avian virus hemagglutinin (HA) after interspecies transmission and to determine the amino acid substitutions responsible for these alterations, we studied the HAs of the initial isolates from the human pandemics of 1957 (H2N2) and 1968 (H3N2), the European swine epizootic of 1979 (H1N1), and the seal epizootic of 1992 (H3N3), all of which were caused by the introduction of avian virus HAs into these species. The viruses were assayed for their ability to bind the synthetic sialylglycopolymers 3′SL-PAA and 6′SLN-PAA, which contained, respectively, 3′-sialyllactose (the receptor determinant preferentially recognized by avian influenza viruses) and 6′-sialyl(N-acetyllactosamine) (the receptor determinant for human viruses). Avian and seal viruses bound 6′SLN-PAA very weakly, whereas the earliest available human and swine epidemic viruses bound this polymer with a higher affinity. For the H2 and H3 strains, a single mutation, 226Q→L, increased binding to 6′SLN-PAA, while among H1 swine viruses, the 190E→D and 225G→E mutations in the HA appeared important for the increased affinity of the viruses for 6′SLN-PAA. Amino acid substitutions at positions 190 and 225 with respect to the avian virus consensus sequence are also present in H1 human viruses, including those that circulated in 1918, suggesting that substitutions at these positions are important for the generation of H1 human pandemic strains. These results show that the receptor-binding specificity of the HA is altered early after the transmission of an avian virus to humans and pigs and, therefore, may be a prerequisite for the highly effective replication and spread which characterize epidemic strains.

scholarly journals Antibodies to Highly Pathogenic A/H5Nx (Clade 2.3.4.4) Influenza Viruses in the Sera of Vietnamese Residents

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 394
Author(s):  
Tatyana Ilyicheva ◽  
Vasily Marchenko ◽  
Olga Pyankova ◽  
Anastasia Moiseeva ◽  
Tran Thi Nhai ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Wide Spectrum ◽  
Influenza Viruses ◽  
Serum Samples ◽  
Socialist Republic ◽  
Highly Pathogenic ◽  
Virus Variant ◽  
Human Sera ◽  
Hemagglutinin Inhibition

To cause a pandemic, an influenza virus has to overcome two main barriers. First, the virus has to be antigenically new to humans. Second, the virus has to be directly transmitted from humans to humans. Thus, if the avian influenza virus is able to pass the second barrier, it could cause a pandemic, since there is no immunity to avian influenza in the human population. To determine whether the adaptation process is ongoing, analyses of human sera could be conducted in populations inhabiting regions where pandemic virus variant emergence is highly possible. This study aimed to analyze the sera of Vietnamese residents using hemagglutinin inhibition reaction (HI) and microneutralization (MN) with A/H5Nx (clade 2.3.4.4) influenza viruses isolated in Vietnam and the Russian Federation in 2017–2018. In this study, we used sera from 295 residents of the Socialist Republic of Vietnam collected from three groups: 52 samples were collected from households in Nam Dinh province, where poultry deaths have been reported (2017); 96 (2017) and 147 (2018) samples were collected from patients with somatic but not infectious diseases in Hanoi. In all, 65 serum samples were positive for HI, at least to one H5 virus used in the study. In MN, 47 serum samples neutralizing one or two viruses at dilutions of 1/40 or higher were identified. We postulate that the rapidly evolving A/H5Nx (clade 2.3.4.4) influenza virus is possibly gradually adapting to the human host, insofar as healthy individuals have antibodies to a wide spectrum of variants of that subtype.

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