The origin of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing the global coronavirus disease 19 (COVID-19) pandemic, remains a mystery. Current evidence suggests a likely spillover into humans from an animal reservoir. Understanding the host range and identifying animal species that are susceptible to SARS-CoV-2 infection may help to elucidate the origin of the virus and the mechanisms underlying cross-species transmission to humans. Here we demonstrated that white-tailed deer (Odocoileus virginianus), an animal species in which the angiotensin converting enzyme 2 (ACE2) – the SARS-CoV-2 receptor – shares a high degree of similarity to humans, are highly susceptible to infection. Intranasal inoculation of deer fawns with SARS-CoV-2 resulted in established subclinical viral infection and shedding of infectious virus in nasal secretions. Notably, infected animals transmitted the virus to non-inoculated contact deer. Viral RNA was detected in multiple tissues 21 days post-inoculation (pi). All inoculated and indirect contact animals seroconverted and developed neutralizing antibodies as early as day 7 pi. The work provides important insights into the animal host range of SARS-CoV-2 and identifies white-tailed deer as a susceptible wild animal species to the virus. IMPORTANCE Given the presumed zoonotic origin of SARS-CoV-2, the human-animal-environment interface of COVID-19 pandemic is an area of great scientific and public- and animal-health interest. Identification of animal species that are susceptible to infection by SARS-CoV-2 may help to elucidate the potential origin of the virus, identify potential reservoirs or intermediate hosts, and define the mechanisms underlying cross-species transmission to humans. Additionally, it may also provide information and help to prevent potential reverse zoonosis that could lead to the establishment of a new wildlife hosts. Our data show that upon intranasal inoculation, white-tailed deer became subclinically infected and shed infectious SARS-CoV-2 in nasal secretions and feces. Importantly, indirect contact animals were infected and shed infectious virus, indicating efficient SARS-CoV-2 transmission from inoculated animals. These findings support the inclusion of wild cervid species in investigations conducted to assess potential reservoirs or sources of SARS-CoV-2 of infection.

The COVID-19 pandemic caused by the SARS-CoV-2 virus remains a global public health crisis. Although widespread vaccination campaigns are underway, their efficacy is reduced owing to emerging variants of concern1,2. Development of host-directed therapeutics and prophylactics could limit such resistance and offer urgently needed protection against variants of concern3,4. Attractive pharmacological targets to impede viral entry include type-II transmembrane serine proteases (TTSPs) such as TMPRSS2; these proteases cleave the viral spike protein to expose the fusion peptide for cell entry, and thus have an essential role in the virus lifecycle5,6. Here we identify and characterize a small-molecule compound, N-0385, which exhibits low nanomolar potency and a selectivity index of higher than 106 in inhibiting SARS-CoV-2 infection in human lung cells and in donor-derived colonoids7. In Calu-3 cells it inhibits the entry of the SARS-CoV-2 variants of concern B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.617.2 (Delta). Notably, in the K18-human ACE2 transgenic mouse model of severe COVID-19, we found that N-0385 affords a high level of prophylactic and therapeutic benefit after multiple administrations or even after a single administration. Together, our findings show that TTSP-mediated proteolytic maturation of the spike protein is critical for SARS-CoV-2 infection in vivo, and suggest that N-0385 provides an effective early treatment option against COVID-19 and emerging SARS-CoV-2 variants of concern.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) emerged as the cause of a global pandemic in 2019-2020. In March 2020 New York City became the USA epicenter for the pandemic. On March 27, 2020 a Malayan tiger (Panthera tigris jacksoni) at the Bronx Zoo in New York City developed a cough and wheezing with subsequent inappetence.Over the next week, an additional Malayan tiger and two Amur tigers (P. t. altaica) in the same building and three lions (Panthera leo krugeri) in a separate building also became ill. The index case was immobilized, and physical examination and bloodwork results were unremarkable.Thoracic radiography and ultrasonography revealed peribronchial cuffing with bronchiectasis, and mild lung consolidation with alveolar-interstitial syndrome, respectively. SARS-CoV-2 RNA was identified by real-time, reverse transcriptase PCR (rRT-PCR) on oropharyngeal and nasal swabs and tracheal wash fluid. Cytologic examination of tracheal wash fluid revealed necrosis, and viral RNA was detected in necrotic cells by in situ hybridization, confirming virusassociated tissue damage. SARS-CoV-2 was isolated from the tracheal wash fluid of the index case, as well as the feces from one Amur tiger and one lion. Fecal viral RNA shedding was confirmed in all seven clinical cases and an asymptomatic Amur tiger. Respiratory signs abated within 1-5 days for most animals, though persisted intermittently for 16 days in the index case.Fecal RNA shedding persisted for as long as 35 days beyond cessation of respiratory signs. This case series describes the clinical presentation, diagnostic evaluation, and management of tigers and lions infected with SARS-CoV-2, and describes the duration of viral RNA fecal shedding in these cases. This report documents the first known natural transmission of SARS-CoV-2 from humans to animals in the USA, and is the first report of SARS-CoV-2 in non-domestic felids..

Feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1) are the two primary causes of upper respiratory tract disease in cats. The aim of this study was to demonstrate the distribution of FCV and FHV-1 among the feline population of several counties in Rio Grande do Sul State, Brazil. To this end, conjunctival and nasal swabs were collected from 302 cats from different locations, including households, breeding catteries, veterinary clinics, animal hospitals and experimental research facilities. The samples were collected between July 2006 to June 2009. The virus isolation was performed in CRFK cells and, subsequently, the identification was confirmed by PCR. FCV, FHV-1, or both were isolated from 55 cats from 28 different locations. FCV alone was isolated from 52.7% (29/55) of the animals that tested positively, FHV-1 alone was isolated from 38.2% (21/55) of the animals that tested positively, and co-infection were detected in 9.1% (5/55) of the animals that tested positively. Virus detection was more prevalent in cats that were less than 1 year old, among animals that shared a living space with other cats, and females. FCV and FHV-1 were isolated from vaccinated cats. In addition, both viruses were isolated from cats that showed no signs of disease. The results suggest that a carrier state is common for both viruses in the evaluated population. A search for other causes of respiratory disease in that population is necessary; and further studies relating to the molecular characterization of viruses and vaccine efficacy are also necessary.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19) in humans, has a broad host range, and is able to infect domestic and wild animal species. Notably, white-tailed deer (WTD, Odocoileus virginianus), the most widely distributed cervid species in the Americas, were shown to be highly susceptible to SARS-CoV-2 in challenge studies and reported natural infection/exposure rates approaching 30–40% in free-ranging WTD in the U.S. Thus, understanding the infection and transmission dynamics of SARS-CoV-2 in WTD is critical to prevent future zoonotic transmission to humans, at the human-WTD interface during hunting or venison farming, and for implementation of effective disease control measures. Here, we demonstrated that following intranasal inoculation with SARS-CoV-2 B.1 lineage, WTD fawns (~8-month-old) shed infectious virus up to day 5 post-inoculation (pi), with high viral loads shed in nasal and oral secretions. This resulted in efficient deer-to-deer transmission on day 3 pi. Consistent a with lack of infectious SARS-CoV-2 shedding after day 5 pi, no transmission was observed to contact animals added on days 6 and 9 pi. We have also investigated the tropism and sites of SARS-CoV-2 replication in adult WTD (3–4 years of age). Infectious virus was detected up to day 6 pi in nasal secretions, and from various respiratory-, lymphoid-, and central nervous system tissues, indicating broad tissue tropism and multiple sites of virus replication. The study provides important insights on the infection and transmission dynamics of SARS-CoV-2 in WTD, a wild animal species that is highly susceptible to infection and with the potential to become a reservoir for the virus in the field.

The origin of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus causing the global coronavirus disease 19 (COVID-19) pandemic, remains a mystery. Current evidence suggests a likely spillover into humans from an animal reservoir. Understanding the host range and identifying animal species that are susceptible to SARS-CoV-2 infection may help to elucidate the origin of the virus and the mechanisms underlying cross-species transmission to humans. Here we demonstrated that white-tailed deer (Odocoileus virginianus), an animal species in which the angiotensin converting enzyme 2 (ACE2) – the SARS-CoV-2 receptor – shares a high degree of similarity to humans, are highly susceptible to infection. Intranasal inoculation of deer fawns with SARS-CoV-2 resulted in established subclinical viral infection and shedding of infectious virus in nasal secretions. Notably, infected animals transmitted the virus to non-inoculated contact deer. Viral RNA was detected in multiple tissues 21 days post-inoculation (pi). All inoculated and indirect contact animals seroconverted and developed neutralizing antibodies as early as day 7 pi. The work provides important insights into the animal host range of SARS-CoV-2 and identifies white-tailed deer as a susceptible wild animal species to the virus.IMPORTANCEGiven the presumed zoonotic origin of SARS-CoV-2, the human-animal-environment interface of COVID-19 pandemic is an area of great scientific and public- and animal-health interest. Identification of animal species that are susceptible to infection by SARS-CoV-2 may help to elucidate the potential origin of the virus, identify potential reservoirs or intermediate hosts, and define the mechanisms underlying cross-species transmission to humans. Additionally, it may also provide information and help to prevent potential reverse zoonosis that could lead to the establishment of a new wildlife hosts. Our data show that upon intranasal inoculation, white-tailed deer became subclinically infected and shed infectious SARS-CoV-2 in nasal secretions and feces. Importantly, indirect contact animals were infected and shed infectious virus, indicating efficient SARS-CoV-2 transmission from inoculated animals. These findings support the inclusion of wild cervid species in investigations conducted to assess potential reservoirs or sources of SARS-CoV-2 of infection.

The parapoxvirus Orf virus (ORFV), has long been recognized for its immunomodulatory properties in permissive and non-permissive animal species. Here, a new recombinant ORFV expressing the full-length spike (S) protein of Porcine epidemic diarrhea virus (PEDV) was generated and its immunogenicity and protective efficacy were evaluated in pigs. The PEDV S was inserted into the ORFV121 gene locus, an immunomodulatory gene that inhibits activation of the NF-κB signalling pathway and contributes to ORFV virulence in the natural host. The recombinant ORFV-PEDV-S virus efficiently and stably expressed the PEDV S protein in cell culture in vitro. Three intramuscular (IM) immunizations with the recombinant ORFV-PEDV-S in 3-week-old pigs elicited robust serum IgG, IgA and neutralizing antibody responses against PEDV. Additionally, IM immunization with the recombinant ORFV-PEDV-S virus protected pigs from clinical signs of porcine epidemic diarrhoea (PED) and reduced virus shedding in faeces upon challenge infection. These results demonstrate the suitability of ORFV121 gene locus as an insertion site for heterologous gene expression and delivery by ORFV-based viral vectors. Additionally, the results provide evidence of the potential of ORFV as a vaccine delivery vector for enteric viral diseases of swine. This study may have important implications for future development of ORFV-vectored vaccines for swine.

Isolados do vírus da diarréia viral bovina (BVDV) apresentam grande diversidade genética e antigênica, o que pode dificultar o diagnóstico e a formulação de vacinas. O presente trabalho apresenta um perfil genotípico e antigênico de 20 amostras do BVDV isoladas no Estado do Rio Grande do Sul entre 2000 e 2010. As amostras foram oriundas de uma variedade de condições clínicas, que incluíam doença respiratória ou gastroentérica aguda ou crônica, lesões cutâneas, abortos, animais com crescimento retardado, além de animais persistentemente infectados (PI). A maioria das amostras (19 ou 95%) pertence ao biótipo não-citopático (NCP); enquanto um isolado apresentou uma mistura de vírus NCP e citopático (CP). O sequenciamento e análise filogenética de uma região de 270 nucleotídeos da região 5' não-traduzida do genoma viral permitiu identificar 9 isolados de BVDV-2 (45%) e 8 isolados de BVDV-2 (40%). Três amostras não agruparam filogeneticamente com nenhum dos genótipos, sendo classificados como pestivírus atípicos. Não foi possível associar os genótipos ou subgenótipos com as condições clínicas e, tanto os BVDV-1 quanto os BVDV-2 estavam envolvidos em diferentes síndromes clínico-patológicas. Análise de reatividade com um painel de 19 anticorpos monoclonais (AcMs) revelou uma variabilidade marcante na glicoproteína principal do envelope (E2) entre vírus do mesmo genótipo, e sobretudo, entre vírus de genótipos diferentes. Testes de neutralização viral (SN) com anti-soro de cepas de referência de BVDV-1 e BVDV-2 frente às amostras isoladas revelaram níveis variáveis de reatividade cruzada entre vírus do mesmo genótipo, e reatividade muito baixa ou ausente entre vírus de genótipos diferentes. Esses resultados indicam uma frequência semelhante de BVDV-1 e BVDV-2 na população estudada, confirmam a marcante variabilidade antigênica e reforçam a necessidade de se incluir vírus dos dois genótipos nas vacinas. Finalmente, indicam a presença de pestivírus atípicos circulantes na população bovina do RS.