Browsing by Author "Ávila, Claudia"

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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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    Highly Pathogenic Avian Influenza A(H5N1) Clade 2.3.4.4b Virus in Wild Birds, Chile
    (2023) Ariyama, Naomi; Pardo-Roa, Catalina; Muñoz, Gabriela; Aguayo, Carolina; Ávila, Claudia; Mathieu, Christian; Almonacid Cárdenas, Leonardo Iván; Medina, Rafael; Brito, Barbara; Johow, Magdalena; Neira, Víctor
    In December 2022, highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b virus emerged in Chile. We detected H5N1 virus in 93 samples and obtained 9 whole-genome sequences of strains from wild birds. Phylogenetic analysis suggests multiple viral introductions into South America. Continued surveillance is needed to assess risks to humans and domestic poultry.
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    Neural tube defects prevalence does not increase after modification of the folic acid fortification program in Chile
    (2022) Pardo, Rosa; Vilca, Marcela; Villarroel del Pino, Luis A.; Davalji, Tahera; Obrycki, John F.; Mazumdar, Maitreyi; Ávila, Claudia; Mellado Sagredo, Cecilia
    Background:In 2000, Chile’s Ministry of Health mandated fortification ofwheat flour with folic acid at a concentration of 2.2 mg/kg to prevent neuraltube defects (NTDs), resulting in a 50% reduction in NTD prevalence. Con-cerns about possible collateral effects of high folic acid intake led, in 2009, todecrease the folic acid fortification to 1.8 mg/kg of flour. Our study evaluatedthe impact of this modification on the prevalence of NTDs in Santiago.Methods:This study measured the prevalence of NTDs in live births and still-births born in Santiago. We calculated prevalence ratios (PR) and 95% confi-dence intervals (CI) between pre-folic acid fortification (1999–2000), post-folicacid fortification (2001–2009), and post-modified folic acid fortification (2010–2015) periods for all NTDs and their specific types. We used chi-square tests toanalyze proportions, and a Joinpoint regression to visualize prevalence timetrends.Results:The NTD prevalence for the period 2001–2015 was 8.9 per 10,000births, which represents a 48% reduction (PR=0.52; 95% CI=0.45–0.61;p< .001) from the pre-folic acid fortification period. During 2010–2015, theNTD prevalence was 9.5/10,000 births, which was higher, but not statisticallysignificantly different from 2001 to 2009 prevalence of 8.6/10,000 (PR=1.11;95% CI=0.96–1.30,p=.17).Conclusions:Decreasing the concentration of folic acid fortification was notassociated with a statistically significant change in the prevalence of NTDs.Mandatory folic acid fortification continues to be a safe and highly effectivepolicy to prevent NTDs. Future studies should evaluate the prevalence ofNTDs across Chile and adherence to folic acid fortification mandates