The emergence and ensuing dominance of COVID-19 on the world stage has emphasized the urgency of efficient animal models for the development of therapeutics for and assessment of immune responses to SARS-CoV-2 infection. Shortcomings of current animal models for SARS-CoV-2 include limited lower respiratory disease, divergence from clinical COVID-19 disease, and requirements for host genetic modifications to permit infection. In this study, n = 12 specific-pathogen-free domestic cats were infected intratracheally with SARS-CoV-2 to evaluate clinical disease, histopathologic lesions, and viral infection kinetics at 4 and 8 days post-inoculation; n = 6 sham-inoculated cats served as controls. Intratracheal inoculation of SARS-CoV-2 produced a significant degree of clinical disease (lethargy, fever, dyspnea, and dry cough) consistent with that observed in the early exudative phase of COVID-19. Pulmonary lesions such as diffuse alveolar damage, hyaline membrane formation, fibrin deposition, and proteinaceous exudates were also observed with SARS-CoV-2 infection, replicating lesions identified in people hospitalized with ARDS from COVID-19. A significant correlation was observed between the degree of clinical disease identified in infected cats and pulmonary lesions. Viral loads and ACE2 expression were also quantified in nasal turbinates, distal trachea, lungs, and other organs. Results of this study validate a feline model for SARS-CoV-2 infection that results in clinical disease and histopathologic lesions consistent with acute COVID-19 in humans, thus encouraging its use for future translational studies.
The global outbreak and rapid spread of SARS-CoV-2 created an urgent need for large scale testing of populations. There is a demand for high throughput testing protocols that can be used for efficient and rapid testing of clinical specimens. We evaluated a pooled-PCR protocol for testing nasopharyngeal swabs using known positive/negative and untested clinical samples that were assigned to pools of 5 or 10. Six-hundred and thirty (630) samples were used in this study. Individual positive samples with Ct values as high as 33 could be consistently detected when pooled with 4 negative samples (pool of 5) and individual positive samples with Ct values up to 31 could be consistently detected when pooled with 9 negative samples (pool of 10). Pooling of up to 5 samples can be employed in laboratories for the diagnosis of COVID-19 for efficient utilization of resources, rapid screening of a greater number of people, and faster reporting of test results.
Genomic sequencing has played a major role in understanding the pathogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the current pandemic, it is essential that SARS-CoV-2 viruses are sequenced regularly to determine mutations and genomic modifications in different geographical locations. In this study we sequenced SARS-CoV-2 from 5 clinical samples obtained in Oklahoma, USA during different time points of pandemic presence in the state. One sample from the initial days of the pandemic in the state and 4 during the peak in Oklahoma were sequenced. Previously reported mutations including D614G in S gene, P4715L in ORF1ab, S194L, R203K and G204R in N gene were identified in the genomes sequenced in this study. Possible novel mutations were also detected such as G1167V in S gene, A6269S and P3371S in ORF1ab, T28I in ORF7b, G96R in ORF8. Phylogenetic analysis of the genomes showed similarity to viruses from across the globe. These novel mutations and phylogenetic analysis emphasize the contagious nature of the virus.
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