Last data update: Jun 17, 2024. (Total: 47034 publications since 2009)
Records 1-4 (of 4 Records) |
Query Trace: Todd Davis C [original query] |
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Interspecies transmission from pigs to ferrets of antigenically distinct swine H1 influenza A viruses with loss in reactivity to human vaccine virus antisera as measures of relative zoonotic risk (preprint)
Brian Kimble J , Souza CK , Anderson TK , Arendsee ZW , Hufnagel DE , Young KM , Lewis NS , Todd Davis C , Vincent Baker AL . bioRxiv 2022 13 During the last decade, endemic swine H1 influenza A viruses (IAV) from six different genetic clades of the hemagglutinin gene caused zoonotic infections in humans. The majority of zoonotic events with swine IAV were restricted to a single case with no subsequent transmission. However, repeated introduction of human-seasonal H1N1, continual reassortment between endemic swine IAV, and subsequent drift in the swine host resulted in highly diverse swine IAV with human-origin genes that may become a risk to the human population. To prepare for the potential of a future swine-origin IAV pandemic in humans, public health laboratories selected candidate vaccine viruses (CVV) for use as vaccine seed strains. To assess the pandemic risk of contemporary US swine H1N1 or H1N2 strains, we quantified the genetic diversity of swine H1 HA genes, and identified representative strains from each circulating clade. We then characterized the representative swine IAV against human seasonal vaccine and CVV strains using ferret antisera in hemagglutination inhibition assays (HI). HI assays revealed that 1A.3.3.2 (pdm) and 1B.2.1 (delta-2) demonstrated strong cross reactivity to human seasonal vaccines or CVVs. However, swine IAV from three clades that represent more than 50% of the detected swine IAVs in the USA showed significant reduction in cross-reactivity compared to the closest CVV virus: 1A.1.1.3 (alpha-deletion), 1A.3.3.3-clade 3 (gamma), and 1B.2.2.1 (delta-1a). Representative viruses from these three clades were further characterized in a pig-to-ferret transmission model and shown to exhibit variable transmission efficiency. Our data prioritize specific genotypes of swine H1N1 and H1N2 to further investigate in the risk they pose to the human population. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. |
Cross-neutralization and viral fitness of SARS-CoV-2 Omicron sublineages.
Xia H , Yeung J , Kalveram B , Bills CJ , Chen JY , Kurhade C , Zou J , Widen SG , Mann BR , Kondor R , Todd Davis C , Zhou B , Wentworth DE , Xie X , Shi PY . Emerg Microbes Infect 2023 12 (1) 1-19 ![]() The rapid evolution of SARS-CoV-2 Omicron sublineages mandates a better understanding of viral replication and cross-neutralization among these sublineages. Here we used K18-hACE2 mice and primary human airway cultures to examine the viral fitness and antigenic relationship among Omicron sublineages. In both K18-hACE2 mice and human airway cultures, Omicron sublineages exhibited a replication order of BA.5 ≥ BA.2 ≥ BA.2.12.1 > BA.1; no difference in body weight loss was observed among different sublineage-infected mice. The BA.1-, BA.2-, BA.2.12.1-, and BA.5-infected mice developed distinguishable cross-neutralizations against Omicron sublineages, but exhibited little neutralization against the index virus (i.e., USA-WA1/2020) or the Delta variant. Surprisingly, the BA.5-infected mice developed higher neutralization activity against heterologous BA.2 and BA.2.12.1 than that against homologous BA.5; serum neutralizing titers did not always correlate with viral replication levels in infected animals. Our results revealed a distinct antigenic cartography of Omicron sublineages and support the bivalent vaccine approach. |
Pathogenesis and Transmission of Human Seasonal and Swine-origin A(H1) Influenza Viruses in the Ferret Model.
Pulit-Penaloza JA , Brock N , Jones J , Belser JA , Jang Y , Sun X , Thor S , Pappas C , Zanders N , Tumpey TM , Todd Davis C , Maines TR . Emerg Microbes Infect 2022 11 (1) 1-20 ![]() Influenza A viruses (IAVs) in the swine reservoir constantly evolve, resulting in expanding genetic and antigenic diversity of strains that occasionally cause infections in humans and pose threat of emerging as a strain capable of human-to-human transmission. For these reasons, there is an ongoing need for surveillance and characterization of newly emerging strains to aid pandemic preparedness efforts, particularly for the selection of candidate vaccine viruses and conducting risk assessments. Here, we performed a parallel comparison of the pathogenesis and transmission of genetically and antigenically diverse swine-origin A(H1N1) variant (v) and A(H1N2)v, and human seasonal A(H1N1)pdm09 IAVs using the ferret model. Both groups of viruses were capable of replication in the ferret upper respiratory tract; however, variant viruses were more frequently isolated from the lower respiratory tract as compared to the human-adapted viruses. Regardless of virus origin, observed clinical signs of infection differed greatly between strains, with some viruses causing nasal discharge, sneezing and, in some instances, diarrhea in ferrets. The most striking difference between the viruses was the ability to transmit through the air. Human-adapted viruses were capable of airborne transmission between all ferret pairs. In contrast, only one out of the four tested variant viruses was able to transmit via the air as efficiently as the human-adapted viruses. Overall, this work highlights the need for sustained monitoring of emerging swine IAVs to identify strains of concern such as those that are antigenically different from vaccine strains and that possess adaptations required for efficient respiratory droplet transmission in mammals. |
Laboratory evaluation of two point-of-care detection systems for early and accurate detectaion of influenza in the Lao People's Democratic Republic.
Kittikraisak W , Khamphaphongphane B , Xayadeth S , Oulay VS , Khanthamaly V , Sengvilaipaseuth O , Davis CT , Yang G , Zanders N , Mott JA , Xangsayarath P . Int J Infect Dis 2020 104 214-221 ![]() BACKGROUND: We evaluated molecular-based point-of-care influenza detection systems in a laboratory prior to the field evaluations of on-site specimen testing. METHODS: Performance of 1) insulated isothermal PCR on the POCKIT(TM) device and 2) real-time reverse transcription-PCR (rRT-PCR) on a MyGo Mini device were evaluated using human clinical specimens, beta-propiolactone-inactivated influenza viruses, and RNA controls. The rRT-PCR carried out on a CXF-96(TM) Real-time Detection System was used as a gold standard for comparisons. RESULTS: Both systems demonstrated 100% sensitivity and specificity and test results were in 100% agreement with the gold standard. POCKIT(TM) only correctly identified influenza A(M gene) in clinical specimens due to the unavailability of typing and subtyping reagents for human influenza viruses, while MyGo Mini had either a one log higher or the same sensitivity in detecting influenza viruses in clinical specimens compared to the gold standard. For inactivated viruses and/or viral RNA, the analytic sensitivity of POCKIT(TM) was shown to be comparable to, or more sensitive, than the gold standard. The analytic sensitivity of MyGo Mini had mixed results depending on the types and subtypes of influenza viruses. CONCLUSIONS: The performance of the two systems in a laboratory is promising and supports further evaluation in field settings. |
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