RESUMEN
Subtype H10 influenza A viruses (IAVs) have been recovered from domestic poultry and various aquatic bird species, and sporadic transmission of these IAVs from avian species to mammals (i.e., human, seal, and mink) are well documented. In 2015, we isolated four H10N7 viruses from gulls in Iceland. Genomic analyses showed four gene segments in the viruses were genetically associated with H10 IAVs that caused influenza outbreaks and deaths among European seals in 2014. Antigenic characterization suggested minimal antigenic variation among these H10N7 isolates and other archived H10 viruses recovered from human, seal, mink, and various avian species in Asia, Europe, and North America. Glycan binding preference analyses suggested that, similar to other avian-origin H10 IAVs, these gull-origin H10N7 IAVs bound to both avian-like alpha 2,3-linked sialic acids and human-like alpha 2,6-linked sialic acids. However, when the gull-origin viruses were compared with another Eurasian avian-origin H10N8 IAV, which caused human infections, the gull-origin virus showed significantly higher binding affinity to human-like glycan receptors. Results from a ferret experiment demonstrated that a gull-origin H10N7 IAV replicated well in turbinate, trachea, and lung, but replication was most efficient in turbinate and trachea. This gull-origin H10N7 virus can be transmitted between ferrets through the direct contact and aerosol routes, without prior adaptation. Gulls share their habitat with other birds and mammals and have frequent contact with humans; therefore, gull-origin H10N7 IAVs could pose a risk to public health. Surveillance and monitoring of these IAVs at the wild bird-human interface should be continued.IMPORTANCE Subtype H10 avian influenza A viruses (IAVs) have caused sporadic human infections and enzootic outbreaks among seals. In the fall of 2015, H10N7 viruses were recovered from gulls in Iceland, and genomic analyses showed that the viruses were genetically related with IAVs that caused outbreaks among seals in Europe a year earlier. These gull-origin viruses showed high binding affinity to human-like glycan receptors. Transmission studies in ferrets demonstrated that the gull-origin IAV could infect ferrets, and that the virus could be transmitted between ferrets through direct contact and aerosol droplets. This study demonstrated that avian H10 IAV can infect mammals and be transmitted among them without adaptation. Thus, avian H10 IAV is a candidate for influenza pandemic preparedness and should be monitored in wildlife and at the animal-human interface.
Asunto(s)
Hurones/virología , Subtipo H10N7 del Virus de la Influenza A/patogenicidad , Infecciones por Orthomyxoviridae/transmisión , Infecciones por Orthomyxoviridae/virología , Aerosoles , Animales , Animales Salvajes/virología , Aves/virología , Línea Celular , Charadriiformes/virología , Genoma Viral , Humanos , Islandia , Subtipo H10N7 del Virus de la Influenza A/clasificación , Subtipo H10N7 del Virus de la Influenza A/genética , Subtipo H10N7 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/virología , Infecciones por Orthomyxoviridae/epidemiología , Infecciones por Orthomyxoviridae/patología , Pandemias , Filogenia , Polisacáridos , Sistema Respiratorio/patología , Sistema Respiratorio/virología , Alineación de SecuenciaRESUMEN
During the outbreaks of highly pathogenic avian influenza (HPAI) H5N6 viruses in 2016 in South Korea, novel H5N8 viruses were also isolated from migratory birds. Phylogenetic analysis revealed that the HA gene of these H5N8 viruses belonged to clade 2.3.4.4, similarly to recent H5Nx viruses, and originated from A/Brk/Korea/Gochang1/14(H5N8), a minor lineage of H5N8 that appeared in 2014 and then disappeared. At least four reassortment events occurred with different subtypes (H5N8, H7N7, H3N8 and H10N7) and a chicken challenge study revealed that they were classified as HPAI viruses according to OIE criteria.
Asunto(s)
Brotes de Enfermedades/veterinaria , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Subtipo H5N8 del Virus de la Influenza A/genética , Gripe Aviar/epidemiología , Filogenia , Virus Reordenados/genética , Animales , Animales Salvajes , Aves/virología , Pollos , Genotipo , Subtipo H10N7 del Virus de la Influenza A/clasificación , Subtipo H10N7 del Virus de la Influenza A/genética , Subtipo H10N7 del Virus de la Influenza A/aislamiento & purificación , Subtipo H3N8 del Virus de la Influenza A/clasificación , Subtipo H3N8 del Virus de la Influenza A/genética , Subtipo H3N8 del Virus de la Influenza A/aislamiento & purificación , Subtipo H5N8 del Virus de la Influenza A/clasificación , Subtipo H5N8 del Virus de la Influenza A/aislamiento & purificación , Subtipo H7N7 del Virus de la Influenza A/clasificación , Subtipo H7N7 del Virus de la Influenza A/genética , Subtipo H7N7 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/virología , Filogeografía , Virus Reordenados/clasificación , Virus Reordenados/aislamiento & purificación , República de Corea/epidemiologíaRESUMEN
UNLABELLED: Influenza A viruses are major pathogens for humans, domestic animals, and wildlife, and these viruses occasionally cross the species barrier. In spring 2014, increased mortality of harbor seals (Phoca vitulina), associated with infection with an influenza A(H10N7) virus, was reported in Sweden and Denmark. Within a few months, this virus spread to seals of the coastal waters of Germany and the Netherlands, causing the death of thousands of animals. Genetic analysis of the hemagglutinin (HA) and neuraminidase (NA) genes of this seal influenza A(H10N7) virus revealed that it was most closely related to various avian influenza A(H10N7) viruses. The collection of samples from infected seals during the course of the outbreak provided a unique opportunity to follow the adaptation of the avian virus to its new seal host. Sequence data for samples collected from 41 different seals from four different countries between April 2014 and January 2015 were obtained by Sanger sequencing and next-generation sequencing to describe the molecular epidemiology of the seal influenza A(H10N7) virus. The majority of sequence variation occurred in the HA gene, and some mutations corresponded to amino acid changes not found in H10 viruses isolated from Eurasian birds. Also, sequence variation in the HA gene was greater at the beginning than at the end of the epidemic, when a number of the mutations observed earlier had been fixed. These results imply that when an avian influenza virus jumps the species barrier from birds to seals, amino acid changes in HA may occur rapidly and are important for virus adaptation to its new mammalian host. IMPORTANCE: Influenza A viruses are major pathogens for humans, domestic animals, and wildlife. In addition to the continuous circulation of influenza A viruses among various host species, cross-species transmission of influenza A viruses occurs occasionally. Wild waterfowl and shorebirds are the main reservoir for most influenza A virus subtypes, and spillover of influenza A viruses from birds to humans or other mammalian species may result in major outbreaks. In the present study, various sequencing methods were used to elucidate the genetic changes that occurred after the introduction and subsequent spread of an avian influenza A(H10N7) virus among harbor seals of northwestern Europe by use of various samples collected during the outbreak. Such detailed knowledge of genetic changes necessary for introduction and adaptation of avian influenza A viruses to mammalian hosts is important for a rapid risk assessment of such viruses soon after they cross the species barrier.
Asunto(s)
Variación Genética , Subtipo H10N7 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/epidemiología , Infecciones por Orthomyxoviridae/virología , Phoca/virología , Análisis Espacio-Temporal , Sustitución de Aminoácidos , Animales , Biología Computacional/métodos , Europa (Continente)/epidemiología , Genoma Viral , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Subtipo H10N7 del Virus de la Influenza A/clasificación , Filogenia , FilogeografíaAsunto(s)
Antivirales/farmacología , Inhibidores Enzimáticos/farmacología , Salud Global , Subtipo H10N7 del Virus de la Influenza A/efectos de los fármacos , Gripe Humana/tratamiento farmacológico , Neuraminidasa/antagonistas & inhibidores , Vigilancia de la Población , Farmacorresistencia Viral/genética , Humanos , Subtipo H10N7 del Virus de la Influenza A/clasificación , Subtipo H10N7 del Virus de la Influenza A/genética , Gripe Humana/epidemiología , Gripe Humana/virología , Pruebas de Sensibilidad Microbiana/métodos , Pruebas de Sensibilidad Microbiana/normas , Neuraminidasa/genética , Oseltamivir/farmacología , Polimorfismo de Nucleótido Simple , Guías de Práctica Clínica como Asunto , Organización Mundial de la Salud , Zanamivir/farmacologíaRESUMEN
Since April 2014, an outbreak of influenza in harbor seals has been ongoing in northern Europe. In Denmark during June-August, 152 harbor seals on the island of Anholt were found dead from severe pneumonia. We detected influenza A(H10N7) virus in 2 of 4 seals examined.
Asunto(s)
Subtipo H10N7 del Virus de la Influenza A/clasificación , Subtipo H10N7 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/virología , Phoca/virología , Animales , Dinamarca/epidemiología , Genes Virales , Subtipo H10N7 del Virus de la Influenza A/aislamiento & purificación , Infecciones por Orthomyxoviridae/epidemiología , FilogeniaAsunto(s)
Subtipo H10N7 del Virus de la Influenza A , Infecciones por Orthomyxoviridae/mortalidad , Infecciones por Orthomyxoviridae/virología , Phoca/virología , Animales , Dinamarca/epidemiología , Subtipo H10N7 del Virus de la Influenza A/clasificación , Subtipo H10N7 del Virus de la Influenza A/genética , Infecciones por Orthomyxoviridae/epidemiologíaRESUMEN
In March 2010, an outbreak of low pathogenicity avian influenza A (H10N7) occurred on a chicken farm in Australia. After processing clinically normal birds from the farm, 7 abattoir workers reported conjunctivitis and minor upper respiratory tract symptoms. Influenza virus A subtype H10 infection was detected in 2 workers.