RESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have spilled over from humans to companion and wild animals since the inception of the global COVID-19 pandemic. However, whole genome sequencing data of the viral genomes that infect non-human animal species has been scant. Here, we detected and sequenced a SARS-CoV-2 delta variant (AY.3) in fecal samples from an 11-year-old domestic house cat previously exposed to an owner who tested positive for SARS-CoV-2. Molecular testing of two fecal samples collected 7 days apart yielded relatively high levels of viral RNA. Sequencing of the feline-derived viral genomes showed the two to be identical, and differing by between 4 and 14 single nucleotide polymorphisms in pairwise comparisons to human-derived lineage AY.3 sequences collected in the same geographic area and time period. However, several mutations unique to the feline samples reveal their divergence from this cohort on phylogenetic analysis. These results demonstrate continued spillover infections of emerging SARS-CoV-2 variants that threaten human and animal health, as well as highlight the importance of collecting fecal samples when testing for SARS-CoV-2 in animals. To the authors knowledge, this is the first published case of a SARS-CoV-2 delta variant in a domestic cat in the United States.
RESUMO
Surrogate neutralization assays for SARS-CoV-2 that can be done without biosafety-level-3 containment and across multiple species are desirable. We evaluate a recently developed surrogate virus neutralization test (sVNT) in comparison to 90% plaque reduction neutralization tests (PRNT90) in human, canine, cat and hamster sera and found excellent concordance between the two assays. Using a panel of immune sera to other coronaviruses, we confirm the lack of cross reactivity in sVNT and PRNT90 assays.
RESUMO
In 68 respiratory specimens from a cohort of 35 COVID-19 patients, 32 of them with mild disease, we found SARS coronavirus-2 virus culture and sub-genomic RNA was rarely detectable beyond 8 days after onset of illness although virus RNA by RT-PCR remained detectable for many weeks.
RESUMO
BackgroundThe SARS-CoV-2 virus emerged in December 2019 and caused a pandemic associated with a spectrum of COVID-19 disease ranging from asymptomatic to lethal infection. Serology testing is important for diagnosis of infection, determining infection attack rates and immunity in the population. It also informs vaccine development. Although several serology tests are in use, improving their specificity and sensitivity for early diagnosis on the one hand and for detecting past infection for population-based studies, are priorities. MethodsWe evaluated the anti-SARS-CoV-2 antibody profiles to 15 SARS-CoV-2 antigens by cloning and expressing 15 open reading frames (ORFs) in mammalian cells and screened antibody responses to them in COVID-19 patients using the Luciferase Immunoprecipitation System (LIPS). ResultsThe LIPS technique allowed us to detect antibody responses in COVID-19 patients to 11 of the 15 SARS-CoV-2 antigens tested, identifying novel immunogenic targets. This technique shows that antigens ORF3b and ORF8 allow detection of antibody early in infection in a specific manner and reveals the immuno-dominance of the N antigen in COVID-19 patients. ConclusionOur report provides an unbiased characterization of antibody responses to a range of SARS-CoV-2 antigens. The combination of 3 SARS-CoV-2 antibody LIPS assays, i.e. N, ORF3b, and ORF8, is sufficient to identify all COVID-19 patients of our cohort even at early time-points of illness, whilst Spike alone fails to do so. Furthermore, our study highlights the importance of investigating new immunogens NSP1, ORF3b, ORF7a and ORF8 which may mediate immune functions other than neutralization which may be beneficial or harmful to the patient.
