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Brüssow H. Avian influenza virus cross-infections as test case for pandemic preparedness: From epidemiological hazard models to sequence-based early viral warning systems. Microb Biotechnol 2024; 17:e14389. [PMID: 38227348 PMCID: PMC10832514 DOI: 10.1111/1751-7915.14389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/17/2023] [Accepted: 12/06/2023] [Indexed: 01/17/2024] Open
Abstract
Pandemic preparedness starts with an early warning system of viruses with a pandemic potential. Based on information collected in a multitude of surveys, hazard models were developed identifying influenza viruses presenting a pandemic threat. Scores are attributed for 10 viral traits by expert panels which identified avian influenza viruses (AIV) belonging to subtypes H7N9 and H5N1 as representing the greatest pandemic risk. In 2013, more than 100 human cases infected with AIV H7N9 were observed in China. Case fatality rate (CFR) was high (27%), but the human-to-human transmission rate was low and by serological evidence H7N9 did not spread widely. Nevertheless, until 2019 more than 1500 H7N9 patients were identified characterized by a high CFR of 39%. Serology demonstrated that mild infections with H7N9 were widespread. In 2003, more than 400 people experienced AIV H7N7 cross-infection causing mainly conjunctivitis during a large poultry epidemic in The Netherlands. Between 1996 and 2019, a total of 881 human infections with avian H5N1 viruses were documented showing a CFR of 52%. Outbreaks were centred on South East Asia and showed close associations with epizootics in poultry. Mutations predisposing to human cross-infections were identified in the haemagglutinin (HA) and the RNA polymerase subunit PB2 of human H7N9 isolates. Human H5N1 isolates showed mutations in the receptor binding domain of HA and transmission in mammals could be obtained by as few as four additional aa changes introduced experimentally. Researchers have defined viral point mutations in HA, PB2 and the nucleoprotein NP that allowed AIV to cross the species barrier to mammals with respect to receptor recognition, RNA replication and escape from innate immunity respectively. Based on this insight a sequence-based early warning system for AIV preadapted to human transmission could be envisioned. Mink farms and live poultry markets are prime targets for such sequencing efforts.
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Affiliation(s)
- Harald Brüssow
- Division of Animal and Human Health Engineering, Department of BiosystemsKU LeuvenLeuvenBelgium
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Tanaka YL, Shofa M, Butlertanaka EP, Niazi AM, Hirai T, Mekata H, Saito A. Generation of a Porcine Cell Line Stably Expressing Pig TMPRSS2 for Efficient Isolation of Swine Influenza Virus. Pathogens 2023; 13:18. [PMID: 38251326 PMCID: PMC10818301 DOI: 10.3390/pathogens13010018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/23/2024] Open
Abstract
Pigs are important animals for meat production but can carry several zoonotic diseases, including the Japanese encephalitis virus, Nipah virus, and influenza viruses. Several Orthomyxoviridae and Coronavirinae respiratory viruses require cleavage of envelope proteins to acquire viral infectivity and consequently, need a host protease or the addition of exogenous trypsin for efficient propagation. Host TMPRSS2 is a key protease responsible for viral cleavage. Stable expression of human TMPRSS2 in African green monkey-derived Vero cells can enhance the porcine epidemic diarrhea virus. However, considering the narrow host tropism of viruses, a porcine cell line expressing pig TMPRSS2 could be optimal for replicating pig-derived viruses. Herein, we generated and evaluated a pig-derived PK-15 cell line stably expressing pig TMPRSS2. This cell line markedly (>1000-fold) and specifically enhanced the growth of influenza viruses. Furthermore, we demonstrated the usefulness of a PK-15 cell line lacking the Stat2 gene with a stable expression of pig TMPRSS2 for efficient virus isolation from clinical samples in the presence of type I interferons. Therefore, PK-15 cells expressing pig TMPRSS2 could be a valuable and promising tool for virus isolation, vaccine production, and virological studies of TMPRSS2-dependent viruses.
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Affiliation(s)
- Yuri L Tanaka
- Laboratory of Veterinary Microbiology, Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 8892192, Japan
| | - Maya Shofa
- Laboratory of Veterinary Microbiology, Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 8892192, Japan
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki 8891692, Japan
| | - Erika P Butlertanaka
- Laboratory of Veterinary Microbiology, Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 8892192, Japan
| | - Ahmad Massoud Niazi
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki 8891692, Japan
- Laboratory of Veterinary Pathology, Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 8892192, Japan
| | - Takuya Hirai
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki 8891692, Japan
- Laboratory of Veterinary Pathology, Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 8892192, Japan
| | - Hirohisa Mekata
- Center for Animal Disease Control, University of Miyazaki, Miyazaki 8892192, Japan
| | - Akatsuki Saito
- Laboratory of Veterinary Microbiology, Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki 8892192, Japan
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki 8891692, Japan
- Center for Animal Disease Control, University of Miyazaki, Miyazaki 8892192, Japan
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