scholarly journals Influenza Virus Reservoirs and Intermediate Hosts: Dogs, Horses, and New Possibilities for Influenza Virus Exposure of Humans

2014 ◽  
Vol 89 (6) ◽  
pp. 2990-2994 ◽  
Author(s):  
Colin R. Parrish ◽  
Pablo R. Murcia ◽  
Edward C. Holmes
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Mammalian Species ◽  
Influenza Viruses ◽  
Human Populations ◽  
Intermediate Hosts ◽  
New Host ◽  
New Information ◽  
Canine Influenza ◽  
Influenza Outbreaks

Influenza A virus (IAV) infections in hosts outside the main aquatic bird reservoirs occur periodically. Although most such cross-species transmission events result in limited onward transmission in the new host, sustained influenza outbreaks have occurred in poultry and in a number of mammalian species, including humans, pigs, horses, seals, and mink. Recently, two distinct strains of IAV have emerged in domestic dogs, with each circulating widely for several years. Here, we briefly outline what is known about the role of intermediate hosts in influenza emergence, summarize our knowledge of the new canine influenza viruses (CIVs) and how they provide key new information on the process of host adaptation, and assess the risk these viruses pose to human populations.

Equine and canine influenza: a review of current events

2010 ◽  
Vol 11 (1) ◽  
pp. 43-51 ◽  
Author(s):  
E. Paul J. Gibbs ◽  
Tara C. Anderson
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Influenza A ◽  
One Health ◽  
Control Strategies ◽  
Close Association ◽  
Companion Animals ◽  
Emerging Diseases ◽  
Influenza Viruses ◽  
Canine Influenza

AbstractIn the past decade, the pandemics of highly pathogenic avian influenza H5N1 and the novel H1N1 influenza have both illustrated the potential of influenza viruses to rapidly emerge and spread widely in animals and people. Since both of these viruses are zoonotic, these pandemics have been the driving force behind a renewed commitment by the medical and veterinary professions to practice One World, One Health for the control of infectious diseases. The discovery in 2004 that an equine origin H3N8 influenza virus was the cause of an extensive epidemic of respiratory disease in dogs in the USA came as a surprise; at that time dogs were thought to be refractory to infection with influenza viruses. In 2007, a second emerging canine influenza was confirmed in Korea, but this time the causal virus was an H3N2 avian influenza virus. This review focuses on recent events associated with equine and canine influenza viruses. While these viruses do not appear to be zoonotic, the close association between humans and dogs, and to a lesser extent horses, demands that we develop better surveillance and control strategies for emerging diseases in companion animals within the context of One World, One Health.

scholarly journals Emergence of influenza A viruses

2001 ◽  
Vol 356 (1416) ◽  
pp. 1817-1828 ◽  
Author(s):  
R. J. Webby ◽  
R. G. Webster
Keyword(s):  
Intermediate Host ◽  
Influenza A ◽  
Influenza Viruses ◽  
Human Populations ◽  
Aquatic Bird ◽  
Intermediate Hosts ◽  
Aquatic Birds ◽  
Influenza A Viruses ◽  
Bird Populations ◽  
Human Viruses

Pandemic influenza in humans is a zoonotic disease caused by the transfer of influenza A viruses or virus gene segments from animal reservoirs. Influenza A viruses have been isolated from avian and mammalian hosts, although the primary reservoirs are the aquatic bird populations of the world. In the aquatic birds, influenza is asymptomatic, and the viruses are in evolutionary stasis. The aquatic bird viruses do not replicate well in humans, and these viruses need to reassort or adapt in an intermediate host before they emerge in human populations. Pigs can serve as a host for avian and human viruses and are logical candidates for the role of intermediate host. The transmission of avian H5N1 and H9N2 viruses directly to humans during the late 1990s showed that land-based poultry also can serve between aquatic birds and humans as intermediate hosts of influenza viruses. That these transmission events took place in Hong Kong and China adds further support to the hypothesis that Asia is an epicentre for influenza and stresses the importance of surveillance of pigs and live-bird markets in this area.

scholarly journals Origins and Evolutionary Dynamics of H3N2 Canine Influenza Virus

2015 ◽  
Vol 89 (10) ◽  
pp. 5406-5418 ◽  
Author(s):  
Henan Zhu ◽  
Joseph Hughes ◽  
Pablo R. Murcia
Keyword(s):  
Influenza Virus ◽  
North American ◽  
Influenza A ◽  
Influenza Viruses ◽  
Animal Origin ◽  
Influenza A Viruses ◽  
Canine Influenza Virus ◽  
Zoonotic Infections ◽  
Avian Origin ◽  
Canine Influenza

ABSTRACTInfluenza A viruses (IAVs) are maintained mainly in wild birds, and despite frequent spillover infections of avian IAVs into mammals, only a small number of viruses have become established in mammalian hosts. A new H3N2 canine influenza virus (CIV) of avian origin emerged in Asia in the mid-2000s and is now circulating in dog populations of China and South Korea, and possibly in Thailand. The emergence of CIV provides new opportunities for zoonotic infections and interspecies transmission. We examined 14,764 complete IAV genomes together with all CIV genomes publicly available since its first isolation until 2013. We show that CIV may have originated as early as 1999 as a result of segment reassortment among Eurasian and North American avian IAV lineages. We also identified amino acid changes that might have played a role in CIV emergence, some of which have not been previously identified in other cross-species jumps. CIV evolves at a lower rate than H3N2 human influenza viruses do, and viral phylogenies exhibit geographical structure compatible with high levels of local transmission. We detected multiple intrasubtypic and heterosubtypic reassortment events, including the acquisition of the NS segment of an H5N1 avian influenza virus that had previously been overlooked. In sum, our results provide insight into the adaptive changes required by avian viruses to establish themselves in mammals and also highlight the potential role of dogs to act as intermediate hosts in which viruses with zoonotic and/or pandemic potential could originate, particularly with an estimated dog population of ∼700 million.IMPORTANCEInfluenza A viruses circulate in humans and animals. This multihost ecology has important implications, as past pandemics were caused by IAVs carrying gene segments of both human and animal origin. Adaptive evolution is central to cross-species jumps, and this is why understanding the evolutionary processes that shape influenza A virus genomes is key to elucidating the mechanisms underpinning viral emergence. An avian-origin canine influenza virus (CIV) has recently emerged in dogs and is spreading in Asia. We reconstructed the evolutionary history of CIV and show that it originated from both Eurasian and North American avian lineages. We also identified the mutations that might have been responsible for the cross-species jump. Finally, we provide evidence of multiple reassortment events between CIV and other influenza viruses (including an H5N1 avian virus). This is a cause for concern, as there is a large global dog population to which humans are highly exposed.

scholarly journals Temperature-Sensitive Live-Attenuated Canine Influenza Virus H3N8 Vaccine

2016 ◽  
Vol 91 (4) ◽  
Author(s):  
Aitor Nogales ◽  
Laura Rodriguez ◽  
Caroline Chauché ◽  
Kai Huang ◽  
Emma C. Reilly ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Influenza Viruses ◽  
Influenza Vaccines ◽  
Respiratory Pathogen ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Canine Influenza Virus ◽  
Canine Influenza ◽  
Better Than

ABSTRACT Canine influenza is a respiratory disease of dogs caused by canine influenza virus (CIV). CIV subtypes responsible for influenza in dogs include H3N8, which originated from the transfer of H3N8 equine influenza virus to dogs; and the H3N2 CIV, which is an avian-origin virus that adapted to infect dogs. Influenza infections are most effectively prevented through vaccination to reduce transmission and future infection. Currently, only inactivated influenza vaccines (IIVs) are available for the prevention of CIV in dogs. However, the efficacy of IIVs is suboptimal, and novel approaches are necessary for the prevention of disease caused by this canine respiratory pathogen. Using reverse genetics techniques, we have developed a live-attenuated CIV vaccine (LACIV) for the prevention of H3N8 CIV. The H3N8 LACIV replicates efficiently in canine cells at 33°C but is impaired at temperatures of 37 to 39°C and was attenuated compared to wild-type H3N8 CIV in vivo and ex vivo. The LACIV was able to induce protection against H3N8 CIV challenge with a single intranasal inoculation in mice. Immunogenicity and protection efficacy were better than that observed with a commercial CIV H3N8 IIV but provided limited cross-reactive immunity and heterologous protection against H3N2 CIV. These results demonstrate the feasibility of implementing a LAIV approach for the prevention and control of H3N8 CIV in dogs and suggest the need for a new LAIV for the control of H3N2 CIV. IMPORTANCE Two influenza A virus subtypes has been reported in dogs in the last 16 years: the canine influenza viruses (CIV) H3N8 and H3N2 of equine and avian origins, respectively. To date, only inactivated influenza vaccines (IIVs) are available to prevent CIV infections. Here, we report the generation of a recombinant, temperature-sensitive H3N8 CIV as a live-attenuated influenza vaccine (LAIV), which was attenuated in mice and dog tracheal, explants compared to CIV H3N8 wild type. A single dose of H3N8 LACIV showed immunogenicity and protection against a homologous challenge that was better than that conferred with an H3N8 IIV, demonstrating the feasibility of implementing a LAIV approach for the improved control of H3N8 CIV infections in dogs.

scholarly journals Equine and Canine Influenza H3N8 Viruses Show Minimal Biological Differences Despite Phylogenetic Divergence

2015 ◽  
Vol 89 (13) ◽  
pp. 6860-6873 ◽  
Author(s):  
Kurtis H. Feng ◽  
Gaelle Gonzalez ◽  
Lingquan Deng ◽  
Hai Yu ◽  
Victor L. Tse ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Mdck Cells ◽  
Severe Disease ◽  
Biological Properties ◽  
Sialic Acids ◽  
Influenza Viruses ◽  
Host Cells ◽  
Canine Influenza ◽  
Biological Differences

ABSTRACTThe A/H3N8 canine influenza virus (CIV) emerged from A/H3N8 equine influenza virus (EIV) around the year 2000 through the transfer of a single virus from horses to dogs. We defined and compared the biological properties of EIV and CIV by examining their genetic variation, infection, and growth in different cell cultures, receptor specificity, hemagglutinin (HA) cleavage, and infection and growth in horse and dog tracheal explant cultures. Comparison of sequences of viruses from horses and dogs revealed mutations that may be linked to host adaptation and tropism. We prepared infectious clones of representative EIV and CIV strains that were similar to the consensus sequences of viruses from each host. The rescued viruses, including HA and neuraminidase (NA) double reassortants, exhibited similar degrees of long-term growth in MDCK cells. Different host cells showed various levels of susceptibility to infection, but no differences in infectivity were seen when comparing viruses. All viruses preferred α2-3- over α2-6-linked sialic acids for infections, and glycan microarray analysis showed that EIV and CIV HA-Fc fusion proteins bound only to α2-3-linked sialic acids. Cleavage assays showed that EIV and CIV HA proteins required trypsin for efficient cleavage, and no differences in cleavage efficiency were seen. Inoculation of the viruses into tracheal explants revealed similar levels of infection and replication by each virus in dog trachea, although EIV was more infectious in horse trachea than CIV.IMPORTANCEInfluenza A viruses can cross species barriers and cause severe disease in their new hosts. Infections with highly pathogenic avian H5N1 virus and, more recently, avian H7N9 virus have resulted in high rates of lethality in humans. Unfortunately, our current understanding of how influenza viruses jump species barriers is limited. Our aim was to provide an overview and biological characterization of H3N8 equine and canine influenza viruses using various experimental approaches, since the canine virus emerged from horses approximately 15 years ago. We showed that although there were numerous genetic differences between the equine and canine viruses, this variation did not result in dramatic biological differences between the viruses from the two hosts, and the viruses appeared phenotypically equivalent in most assays we conducted. These findings suggest that the cross-species transmission and adaptation of influenza viruses may be mediated by subtle changes in virus biology.

scholarly journals Pandemic Threat Posed by Avian Influenza A Viruses

2001 ◽  
Vol 14 (1) ◽  
pp. 129-149 ◽  
Author(s):  
Taisuke Horimoto ◽  
Yoshihiro Kawaoka
Keyword(s):  
Hong Kong ◽  
Avian Influenza ◽  
Influenza A ◽  
Mammalian Species ◽  
Influenza Viruses ◽  
Human Populations ◽  
Avian Influenza Viruses ◽  
Influenza Pandemics ◽  
Avian Virus ◽  
H5n1 Influenza

SUMMARY Influenza pandemics, defined as global outbreaks of the disease due to viruses with new antigenic subtypes, have exacted high death tolls from human populations. The last two pandemics were caused by hybrid viruses, or reassortants, that harbored a combination of avian and human viral genes. Avian influenza viruses are therefore key contributors to the emergence of human influenza pandemics. In 1997, an H5N1 influenza virus was directly transmitted from birds in live poultry markets in Hong Kong to humans. Eighteen people were infected in this outbreak, six of whom died. This avian virus exhibited high virulence in both avian and mammalian species, causing systemic infection in both chickens and mice. Subsequently, another avian virus with the H9N2 subtype was directly transmitted from birds to humans in Hong Kong. Interestingly, the genes encoding the internal proteins of the H9N2 virus are genetically highly related to those of the H5N1 virus, suggesting a unique property of these gene products. The identification of avian viruses in humans underscores the potential of these and similar strains to produce devastating influenza outbreaks in major population centers. Although highly pathogenic avian influenza viruses had been identified before the 1997 outbreak in Hong Kong, their devastating effects had been confined to poultry. With the Hong Kong outbreak, it became clear that the virulence potential of these viruses extended to humans.

scholarly journals Emergence and Characterization of a Novel Reassortant Canine Influenza Virus Isolated from Cats

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1320
Author(s):  
Jin Zhao ◽  
Wanting He ◽  
Meng Lu ◽  
Haijian He ◽  
Alexander Lai
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Reassortant Virus ◽  
Human Influenza Virus ◽  
Canine Influenza Virus ◽  
Stray Cats ◽  
Wide Range ◽  
Canine Influenza

Cats are susceptible to a wide range of influenza A viruses (IAV). Furthermore, cats can serve as an intermediate host, and transfer avian influenza virus (AIV) H7N2 to a veterinarian. In this report, a novel reassortant influenza virus, designated A/feline/Jiangsu/HWT/2017 (H3N2), and abbreviated as FIV-HWT-2017, was isolated from nasal swab of a symptomatic cat in Jiangsu province, China. Sequence analysis indicated that, whilst the other seven genes were most similar to the avian-origin canine influenza viruses (CIV H3N2) isolated in China, the NS gene was more closely related to the circulating human influenza virus (H3N2) in the region. Therefore, FIV-HWT-2017 is a reassortant virus. In addition, some mutations were identified, and they were similar to a distinctive CIV H3N2 clade. Whether these cats were infected with the reassortant virus was unknown, however, this random isolation of a reassortant virus indicated that domestic or stray cats were “mixing vessel” for IAV cannot be ruled out. An enhanced surveillance for novel influenza virus should include pet and stray cats.

Epidemiological Investigation of Influenza a Viruses in Laboratory Swine and Dogs in Shanghai

2011 ◽  
Vol 393-395 ◽  
pp. 733-736
Author(s):  
Xiao Hua Yang ◽  
Xiao Feng Wei ◽  
Jian Hua Hu ◽  
Xiong Wei Liu ◽  
Shao Jin Chen
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
Positive Sample ◽  
Influenza Viruses ◽  
Security Measures ◽  
Influenza A Viruses ◽  
Canine Influenza ◽  
Epidemiological Situation

Swine and canine influenza, which is acute viral respiratory infectious disease, can do great threat to the health of people and animals. What’s more, swine as an intermediate host for the transmission of avian influenza viruses to humans, it’s very important to supervise the epidemiological situation of swine influenza virus (SIV) infections all over the world. The major aim of this paper was to investigate the epidemiological situation of influenza A viruses in laboratory swine and dogs in shanghai and surrounding area from January 2010 to March 2011. There were 109 throat swabs collected from swine and 35 from dogs. Based on RT-PCR, we have got only one swine influenza virus-positive sample and none canine influenza virus-positive. In addition, this survey not only gives a data about the epidemiological situation of swine and canine influenza, but also provides a basis and guarantee for taking a timely and effective security measures.

scholarly journals Influenza A viruses of avian origin circulating in pigs and other mammals.

2014 ◽  
Vol 61 (3) ◽  
Author(s):  
Kinga Urbaniak ◽  
Andrzej Kowalczyk ◽  
Iwona Markowska-Daniel
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Mammalian Species ◽  
Swine Influenza ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Influenza A Viruses ◽  
Avian Influenza Viruses ◽  
Species Barrier ◽  
New Host

Influenza A viruses (IAVs) are zoonotic agents, capable of crossing the species barriers. Nowadays, they still constitute a great challenge worldwide. The natural reservoir of all influenza A viruses are wild aquatic birds, despite the fact they have been isolated from a number of avian and mammalian species, including humans. Even when influenza A viruses are able to get into another than waterfowl population, they are often unable to efficiently adapt and transmit between individuals. Only in rare cases, these viruses are capable of establishing a new lineage. To succeed a complete adaptation and further transmission between species, influenza A virus must overcome a species barrier, including adaptation to the receptors of a new host, which would allow the virus-cell binding, virus replication and, then, animal-to-animal transmission. For many years, pigs were thought to be intermediate host for adaptation of avian influenza viruses to humans, because of their susceptibility to infection with both, avian and human influenza viruses, which supported hypothesis of pigs as a 'mixing vessel'. In this review, the molecular factors necessary for interspecies transmission are described, with special emphasis on adaptation of avian influenza viruses to the pig population. In addition, this review gives the information about swine influenza viruses circulating around the world with special emphasis on Polish strains.

scholarly journals Emergence of Fatal Avian Influenza in New England Harbor Seals

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
S. J. Anthony ◽  
J. A. St. Leger ◽  
K. Pugliares ◽  
H. S. Ip ◽  
J. M. Chan ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
New England ◽  
Influenza A ◽  
Mammalian Species ◽  
Harbor Seal ◽  
Influenza Viruses ◽  
Mammalian Host ◽  
Harbor Seals ◽  
Lectin Staining

ABSTRACTFrom September to December 2011, 162 New England harbor seals died in an outbreak of pneumonia. Sequence analysis of postmortem samples revealed the presence of an avian H3N8 influenza A virus, similar to a virus circulating in North American waterfowl since at least 2002 but with mutations that indicate recent adaption to mammalian hosts. These include a D701N mutation in the viral PB2 protein, previously reported in highly pathogenic H5N1 avian influenza viruses infecting people. Lectin staining and agglutination assays indicated the presence of the avian-preferred SAα-2,3 and mammalian SAα-2,6 receptors in seal respiratory tract, and the ability of the virus to agglutinate erythrocytes bearing either the SAα-2,3 or the SAα-2,6 receptor. The emergence of this A/harbor seal/Massachusetts/1/2011 virus may herald the appearance of an H3N8 influenza clade with potential for persistence and cross-species transmission.IMPORTANCEThe emergence of new strains of influenza virus is always of great public concern, especially when the infection of a new mammalian host has the potential to result in a widespread outbreak of disease. Here we report the emergence of an avian influenza virus (H3N8) in New England harbor seals which caused an outbreak of pneumonia and contributed to a U.S. federally recognized unusual mortality event (UME). This outbreak is particularly significant, not only because of the disease it caused in seals but also because the virus has naturally acquired mutations that are known to increase transmissibility and virulence in mammals. Monitoring the spillover and adaptation of avian viruses in mammalian species is critically important if we are to understand the factors that lead to both epizootic and zoonotic emergence.

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