Browsing by Author "Araya, Hugo"

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    Cross-species and mammal-to-mammal transmission of clade 2.3.4.4b highly pathogenic avian influenza A/H5N1 with PB2 adaptations
    (2025) Pardo Roa, Catalina; Nelson, Martha I.; Ariyama, Naomi; Aguayo, Carolina; Almonacid Cárdenas, Leonardo Iván; Gonzalez-Reiche, Ana S.; Muñoz, Gabriela; Ulloa, Mauricio; Avila, Claudia; Navarro, Carlos; Reyes, Rodolfo; Castillo Torres, Pablo Nicolás; Mathieu, Christian; Vergara, Ricardo; Gonzalez, Alvaro; Gonzalez, Carmen Gloria; Araya, Hugo; Castillo, Andres; Torres, Juan Carlos; Covarrubias, Paulo; Bustos, Patricia; van Bakel, Harm; Fernandez, Jorge; Fasce, Rodrigo A.; Johow, Magdalena; Neira, Victor; Medina, Rafael
    Highly pathogenic H5N1 avian influenza viruses (HPAIV) belonging to lineage 2.3.4.4b emerged in Chile in December 2022, leading to mass mortality events in wild birds, poultry, and marine mammals and one human case. We detected HPAIV in 7,33% (714/9745) of cases between December 2022-April 2023 and sequenced 177 H5N1 virus genomes from poultry, marine mammals, a human, and wild birds spanning >3800 km of Chilean coastline. Chilean viruses were closely related to Peru's H5N1 outbreak, consistent with north-to-south spread down the Pacific coastline. One human virus and nine marine mammal viruses in Chile had the rare PB2 D701N mammalian-adaptation mutation and clustered phylogenetically despite being sampled 5 weeks and hundreds of kilometers apart. These viruses shared additional genetic signatures, including another mammalian PB2 adaptation (Q591K, n = 6), synonymous mutations, and minor variants. Several mutations were detected months later in sealions in the Atlantic coast, indicating that the pinniped outbreaks on the west and east coasts of South America are genetically linked. These data support sustained mammal-to-mammal transmission of HPAIV in marine mammals over thousands of kilometers of Chile's Pacific coastline, which subsequently continued through the Atlantic coastline.
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    Cross-species and mammal-to-mammal transmission of clade 2.3.4.4b highly pathogenic avian influenza A/H5N1 with PB2 adaptations
    (2025) Pardo Roa, Catalina; Nelson, Martha I.; Ariyama, Naomi; Aguayo, Carolina; Almonacid Cárdenas, Leonardo Iván; Gonzalez-Reiche, Ana S.; Muñoz, Gabriela; Ulloa, Mauricio; Avila, Claudia; Navarro, Carlos; Reyes, Rodolfo; Castillo Torres, Pablo Nicolás; Mathieu, Christian; Vergara, Ricardo; Gonzalez, Alvaro; Gonzalez, Carmen Gloria; Araya, Hugo; Castillo, Andres; Torres, Juan Carlos; Covarrubias, Paulo; Bustos, Patricia; van Bakel, Harm; Fernandez, Jorge; Fasce, Rodrigo A.; Johow, Magdalena; Neira, Victor; Medina, Rafael
    Highly pathogenic H5N1 avian influenza viruses (HPAIV) belonging to lineage 2.3.4.4b emerged in Chile in December 2022, leading to mass mortality events in wild birds, poultry, and marine mammals and one human case. We detected HPAIV in 7,33% (714/9745) of cases between December 2022-April 2023 and sequenced 177 H5N1 virus genomes from poultry, marine mammals, a human, and wild birds spanning >3800 km of Chilean coastline. Chilean viruses were closely related to Peru's H5N1 outbreak, consistent with north-to-south spread down the Pacific coastline. One human virus and nine marine mammal viruses in Chile had the rare PB2 D701N mammalian-adaptation mutation and clustered phylogenetically despite being sampled 5 weeks and hundreds of kilometers apart. These viruses shared additional genetic signatures, including another mammalian PB2 adaptation (Q591K, n = 6), synonymous mutations, and minor variants. Several mutations were detected months later in sealions in the Atlantic coast, indicating that the pinniped outbreaks on the west and east coasts of South America are genetically linked. These data support sustained mammal-to-mammal transmission of HPAIV in marine mammals over thousands of kilometers of Chile's Pacific coastline, which subsequently continued through the Atlantic coastline.
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    Cross-species transmission and PB2 mammalian adaptations of highly pathogenic avian influenza A/H5N1 viruses in Chile
    (2023) Pardo Roa, Catalina; Nelson, Martha I.; Ariyama, Naomi; Aguayo, Carolina; Almonacid Cárdenas, Leonardo Iván; Muñoz, Gabriela; Navarro, Carlos; Ávila, Claudia; Ulloa, Mauricio; Reyes, Rodolfo; Fuentes Luppichini, Eugenia Lucía Angélica; Mathieu, Christian; Vergara, Ricardo; González, Álvaro; González, Carmen Gloria; Araya, Hugo; Fernández, Jorge; Fasce, Rodrigo; Johow, Magdalena; Medina, Rafael; Neira, Víctor
    H5N1 highly pathogenic avian influenza viruses (HPAIV) emerged in wild birds in Chile in December 2022 and spilled over into poultry, marine mammals, and one human. Between December 9, 2022 – March 14, 2023, a coordinated government/academic response detected HPAIV by real-time RT-PCR in 8.5% (412/4735) of samples from 23 avian and 3 mammal orders. Whole-genome sequences obtained from 77 birds and 8 marine mammals revealed that all Chilean H5N1 viruses belong to lineage 2.3.4.4b and cluster monophyletically with viruses from Peru, indicating a single introduction from North America into Peru/Chile. Mammalian adaptations were identified in the PB2 segment: D701N in two sea lions, one human, and one shorebird, and Q591K in the human and one sea lion. Minor variant analysis revealed that D701N was present in 52.9 – 70.9% of sequence reads, indicating the presence of both genotypes within hosts. Further surveillance of spillover events is warranted to assess the emergence and potential onward transmission of mammalian adapted H5N1 HPAIV in South America.
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    First report and genetic characterization of Seneca Valley virus (SVV) in Chile
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2022) Bennett, Benjamin; Urzua-Encina, Constanza; Pardo-Roa, Catalina; Ariyama, Naomi; Lecocq, Claudio; Rivera, Carlos; Badia, Catalina; Suarez, Paulina; Agredo, Michel; Aguayo, Carolina; Avila, Claudia; Araya, Hugo; Perez, Patricio; Berrios, Felipe; Aguero, Belen; Mendieta, Vanessa; Pituco, Edviges Maristela; de Almeida, Iassudara Garcia; Medina, Rafael; Brito, Barbara; Johow, Magdalena; Neira Ramirez, Victor
    Seneca Valley virus (SVV) is a non-enveloped RNA virus and the only member of the Senecavirus A (SVA) species, in the Senecavirus genus, Picornaviridae family. SVV infection causes vesicular lesions in the oral cavity, snout and hooves of pigs. This infection is clinically indistinguishable from trade-restrictions-related diseases such as foot-and-mouth disease. Other clinical manifestations include diarrhoea, anorexia, lethargy, neurological signs and mortality in piglets during their first week of age. Before this study, Chile was considered free of vesicular diseases of swine, including SVV. In April 2022, a suspected case of vesicular disease in a swine farm was reported in Chile. The SVV was confirmed and other vesicular diseases were ruled out. An epidemiological investigation and phylogenetic analyses were performed to identify the origin and extent of the outbreak. Three hundred ninety-five samples from 44 swine farms were collected, including faeces (208), oral fluid (28), processing fluid (14), fresh semen (61), environmental samples (80) and tissue from lesions (4) for real-time RT-PCR detection. Until June 2022, the SVV has been detected in 16 out of 44 farms, all epidemiologically related to the index farm. The closest phylogenetic relationship of the Chilean SVV strain is with viruses collected from swine in California in 2017. The direct cause of the SVV introduction has not yet been identified; however, the phylogenetic analyses suggest the USA as the most likely source. Since the virus remains active in the environment, transmission by fomites such as contaminated feed cannot be discarded. Further studies are needed to determine the risk of the introduction of novel SVV and other transboundary swine pathogens to Chile.
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    Mass mortality event in South American sea lions (Otaria flavescens) correlated to highly pathogenic avian influenza (HPAI) H5N1 outbreak in Chile
    (2023) Ulloa, Mauricio; Fernandez, Antonio; Ariyama, Naomi; Colom-Rivero, Ana; Rivera, Carlos; Nunez, Paula; Sanhueza, Paola; Johow, Magdalena; Araya, Hugo; Torres, Juan Carlos; Gomez, Paola; Munoz, Gabriela; Aguero, Belen; Alegria, Raul; Medina, Rafael; Neira, Victor; Sierra, Eva
    In Chile, since January 2023, a sudden and pronounced increase in strandings and mortality has been observed among South American (SA) sea lions (Otaria flavescens), prompting significant concern. Simultaneously, an outbreak of highly pathogenic avian influenza H5N1 (HPAIV H5N1) in avian species has emerged since December 2022. To investigate the cause of this unexpected mortality, we conducted a comprehensive epidemiological and pathologic study. One hundred sixty-nine SA sea lions were sampled to ascertain their HPAIV H5N1 status, and long-term stranding trends from 2009 to 2023 were analyzed. In addition, two animals were necropsied. Remarkably, a significant surge in SA sea lion strandings was observed initiating in January 2023 and peaking in June 2023, with a count of 4,545 stranded and deceased animals. Notably, this surge in mortality correlates geographically with HPAIV outbreaks affecting wild birds. Among 168 sampled SA sea lions, 34 (20%) tested positive for Influenza A virus, and 21 confirmed for HPAIV H5N1 2.3.4.4b clade in tracheal/rectal swab pools. Clinical and pathological evaluations of the two necropsied stranded sea lions revealed prevalent neurological and respiratory signs, including disorientation, tremors, ataxia, and paralysis, as well as acute dyspnea, tachypnea, profuse nasal secretion, and abdominal breathing. The lesions identified in necropsied animals aligned with observed clinical signs. Detection of the virus via immunohistochemistry (IHC) and real-time PCR in the brain and lungs affirmed the findings. The findings provide evidence between the mass mortality occurrences in SA sea lions and HPAIV, strongly indicating a causal relationship. Further studies are needed to better understand the pathogenesis and transmission.