Publications by authors named "Chester D McDowell"

African swine fever virus (ASFV) is an important transboundary animal pathogen with significant impacts on the global swine industry. Overwhelming proinflammatory responses are a major virulence mechanism for ASFV, but the dynamics of these changes during clinical disease are not completely understood. We constructed a detailed portrait of the innate immune responses during acute African swine fever (ASF) at the cellular, transcriptomic, and cytokine levels.

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African swine fever virus (ASFV) and classical swine fever virus (CSFV) are important transboundary animal diseases (TADs) affecting swine. ASFV is a large DNA virus with a genome size of 170-190+ kilobases (kB) belonging to the family , genus Asfivirus. CSFV is a single-stranded RNA virus with a genome size of approximately 12 kB, belonging to the family , genus Pestivirus.

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African swine fever virus (ASFV) and classical swine fever virus (CSFV) are important transboundary animal diseases (TADs) affecting swine. ASFV is a large DNA virus with a genome size of 170-190 kilobases (kB) belonging to the family Asfarviridae, genus Asfivirus. CSFV is a single-stranded RNA virus with genome size of approximately 12 kB belonging to the family Flaviviridae, genus Pestivirus.

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The African swine fever virus (ASFV) causes fatal disease in pigs and is currently spreading globally. Commercially safe vaccines are urgently required. Aiming to generate a novel live attenuated vaccine (LAV), a recombinant ASFV was generated by deleting the viral O174L (PolX) gene.

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Article Synopsis
  • Proteolytic activation of the haemagglutinin glycoprotein is crucial for the infectivity of influenza A virus (IAV), with different proteases targeting different HA motifs.
  • The study utilized CRISPR/Cas 9 technology to create gene-edited knockout (KO) pigs lacking the TMPRSS2 protease to investigate its effects on IAV replication.
  • Results showed that IAV replication was delayed in KO pigs, leading to reduced virus shedding and lower viral loads in the respiratory system, indicating the potential of GE pigs to help control IAV infections and prevent zoonotic transmissions.
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  • Recent outbreaks of HPAIV H5N1 in terrestrial mammals, including dairy cattle, highlight the urgent need for improved monitoring of zoonotic diseases.
  • Researchers detected and characterized the H5N1 virus from environmental samples taken from a Kansas dairy farm, finding unique genetic substitutions not seen in recent 2024 H5N1 isolates.
  • The study suggests that environmental sampling can provide valuable insights into the virus's evolution and stresses the importance of ongoing epidemiological surveillance to track these emerging pathogens.
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Rapid evolution of highly pathogenic avian influenza viruses (HPAIVs) is driven by antigenic drift but also by reassortment, which might result in robust replication in and transmission to mammals. Recently, spillover of clade 2.3.

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Article Synopsis
  • Proteolytic activation of hemagglutinin (HA) in influenza A virus is crucial for its infectivity, with different proteases targeting different HA motifs.
  • * Highly pathogenic avian influenza has a multibasic cleavage site activated by common proteases, while pandemic strains, like H1N1 and H3N2, are activated by trypsin-like proteases like TMPRSS2.
  • * Gene-edited knockout pigs showed delayed virus replication, reduced virus shedding, and less severe pathology compared to wild-type pigs, highlighting the potential of using gene-edited pigs to reduce economic losses and prevent new IAV variants.*
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Since emerging in late 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has repeatedly crossed the species barrier with natural infections reported in various domestic and wild animal species. The emergence and global spread of SARS-CoV-2 variants of concern (VOCs) has expanded the range of susceptible host species. Previous experimental infection studies in cattle using Wuhan-like SARS-CoV-2 isolates suggested that cattle were not likely amplifying hosts for SARS-CoV-2.

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African swine fever virus (ASFV), classical swine fever virus (CSFV), and foot-and-mouth disease virus (FMDV) cause important transboundary animal diseases (TADs) that have a significant economic impact. The rapid and unequivocal identification of these pathogens and distinction from other animal diseases based on clinical symptoms in the field is difficult. Nevertheless, early pathogen detection is critical in limiting their spread and impact as is the availability of a reliable, rapid, and cost-effective diagnostic test.

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Since its first emergence in 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continued to evolve genetically, jump species barriers, and expand its host range. There is growing evidence of interspecies transmission including infection of domestic animals and widespread circulation in wildlife. However, knowledge of SARS-CoV-2 stability in animal biological fluids and their role in transmission is still limited as previous studies focused on human biological fluids.

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SARS-CoV-2 is a zoonotic virus first identified in 2019, and has quickly spread worldwide. The virus is primarily transmitted through respiratory droplets from infected persons; however, the virus-laden excretions can contaminate surfaces which can serve as a potential source of infection. Since the beginning of the pandemic, SARS-CoV-2 has continued to evolve and accumulate mutations throughout its genome leading to the emergence of variants of concern (VOCs) which exhibit increased fitness, transmissibility, and/or virulence.

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African swine fever (ASF) is an infectious viral disease caused by African swine fever virus (ASFV), that causes high mortality in domestic swine and wild boar (). Currently, outbreaks are mitigated through strict quarantine measures and the culling of affected herds, resulting in massive economic losses to the global pork industry. In 2019, an ASFV outbreak was reported in Mongolia, describing a rapidly progressing clinical disease and gross lesions consistent with the acute form of ASF; the virus was identified as a genotype II virus.

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Unlabelled: SARS-CoV-2 is a zoonotic virus which was first identified in 2019, and has quickly spread worldwide. The virus is primarily transmitted through respiratory droplets from infected persons; however, the virus-laden excretions can contaminate surfaces which can serve as a potential source of infection. Since the beginning of the pandemic, SARS-CoV-2 has continued to evolve and accumulate mutations throughout its genome leading to the emergence of variants of concern (VOCs) which exhibit increased fitness, transmissibility, and/or virulence.

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Due to differences in human and murine angiotensin converting enzyme 2 (ACE-2) receptor, initially available SARS-CoV-2 isolates could not infect mice. Here we show that serial passaging of USA-WA1/2020 strain in mouse lungs results in "mouse-adapted" SARS-CoV-2 (MA-SARS-CoV-2) with mutations in S, M, and N genes, and a twelve-nucleotide insertion in the S gene. MA-SARS-CoV-2 infection causes mild disease, with more pronounced morbidity depending on genetic background and in aged and obese mice.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a zoonotic agent capable of infecting humans and a wide range of animal species. Over the duration of the pandemic, mutations in the SARS-CoV-2 spike (S) protein have arisen, culminating in the spread of several variants of concern (VOCs) with various degrees of altered virulence, transmissibility, and neutralizing antibody escape. In this study, we used pseudoviruses that express specific SARS-CoV-2 S protein substitutions and cell lines that express angiotensin-converting enzyme 2 (ACE2) from nine different animal species to gain insights into the effects of VOC mutations on viral entry and antibody neutralization capability.

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Unlabelled: SARS-CoV-2 is a zoonotic agent capable of infecting humans and a wide range of animal species. Over the duration of the pandemic, mutations in the SARS-CoV-2 Spike protein (S) have arisen in circulating viral populations, culminating in the spread of several variants of concern (VOC) with varying degrees of altered virulence, transmissibility, and neutralizing antibody escape. In this study, we employed lentivirus-based pseudotyped viruses that express specific SARS-CoV-2 S protein substitutions and cell lines that stably express ACE2 from nine different animal species to gain insights into the effects of VOC mutations on viral entry and antibody neutralization capability.

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Article Synopsis
  • The COVID-19 pandemic mainly impacts the elderly and those with conditions like obesity and diabetes.
  • Small animal models, specifically mice, are essential for developing and testing vaccines and therapies; the researchers adapted the SARS-CoV-2 virus to effectively infect mice with these health conditions.
  • The study found that the adapted virus worsened the disease in older and diabetic obese mice and identified a key mutation (N501Y) linked to increased transmission in new variants, while also demonstrating that current vaccines are likely effective against these emerging strains.
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