The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reached nearly every country in the world with extraordinary person-to-person transmission. The most likely original source of the virus was spillover from an animal reservoir and subsequent adaptation to humans sometime during the winter of 2019 in Wuhan Province, China. Because of its genetic similarity to SARS-CoV-1, it is probable that this novel virus has a similar host range and receptor specificity. Due to concern for human–pet transmission, we investigated the susceptibility of domestic cats and dogs to infection and potential for infected cats to transmit to naive cats. We report that cats are highly susceptible to infection, with a prolonged period of oral and nasal viral shedding that is not accompanied by clinical signs, and are capable of direct contact transmission to other cats. These studies confirm that cats are susceptible to productive SARS-CoV-2 infection, but are unlikely to develop clinical disease. Further, we document that cats developed a robust neutralizing antibody response that prevented reinfection following a second viral challenge. Conversely, we found that dogs do not shed virus following infection but do seroconvert and mount an antiviral neutralizing antibody response. There is currently no evidence that cats or dogs play a significant role in human infection; however, reverse zoonosis is possible if infected owners expose their domestic pets to the virus during acute infection. Resistance to reinfection holds promise that a vaccine strategy may protect cats and, by extension, humans.

12The pandemic caused by SARS-CoV-2 has reached nearly every country in the world with 13 extraordinary person-to-person transmission. The most likely original source of the virus was 14 spillover from an animal reservoir and subsequent adaptation to humans sometime during the 15 winter of 2019 in Wuhan Province, China. Because of its genetic similarity to SARS-CoV-1, it is 16 likely that this novel virus has a similar host range and receptor specificity. Due to concern for 17 human-pet transmission, we investigated the susceptibility of domestic cats and dogs to infection 18 and potential for infected cats to transmit to naïve cats. We report that cats are highly susceptible 19 to subclinical infection, with a prolonged period of oral and nasal viral shedding that is not 20 accompanied by clinical signs, and are capable of direct contact transmission to other cats. These 21 studies confirm that cats are susceptible to productive SARS-CoV-2 infection, but are unlikely to 22 develop clinical disease. Further, we document that cats develop a robust neutralizing antibody 23 response that prevented re-infection to a second viral challenge. Conversely, we found that dogs 24 do not shed virus following infection, but do mount an anti-viral neutralizing antibody response. 25There is currently no evidence that cats or dogs play a significant role in human exposure; 26 however, reverse zoonosis is possible if infected owners expose their domestic pets during acute 27 infection. Resistance to re-exposure holds promise that a vaccine strategy may protect cats, and 28 by extension humans, to disease susceptibility. 29 30 Introduction 31 32 The COVID-19 pandemic, caused by the SARS-CoV-2 (SARS2) coronavirus, originated in the 33 Wuhan province of China, in late 2019 and within four months spread to nearly every country in 34 the world. Sequence analysis and epidemiological investigations suggest that the virus was of 35 animal-origin, possibly bat, and was first introduced into the human population via an 36 intermediate animal host in the Huanan seafood market in Wuhan, China (Bogoch et al. 2020; 37 Zhou et al. 2020). The virus quickly adapted to humans and human-to-human transmission 38 became the almost immediate source of subsequent infections, with direct contact and aerosol 39 droplets as the primary routes of infection (Li et al. 2020). Early indications suggested that 40 SARS2, much like SARS-CoV-1 (SARS1), infects host cells by binding to the angiotensin-41 converting enzyme 2 (ACE2), a receptor that is expressed in many animal species, although 42 notably not in mice or rats (Wan et al. 2020). Thus, while humans are almost certainly the sole 43 source of infection to other humans, multiple early studies suggest other animals are susceptible 44 to infection as well. 129 130 Dogs (n=3) 131 Dogs were sampled at the same frequency, and using the same methods as cats in Cohort 1 for 132 42 days post-infection. Dogs were not re-challenged. 133 134 Clinical observations 135 Body temperatures were recorded daily for the dur...

Hepadnaviruses are partially double-stranded DNA viruses that infect a variety of species. The prototypical virus in this family is the human hepatitis B virus, which chronically infects approximately 400 million people worldwide and is a risk factor for progressive liver disease and liver cancer. The first hepadnavirus isolated from carnivores was a domestic cat hepadnavirus (DCH), initially identified in Australia and subsequently detected in cats in Europe and Asia. As with all characterized hepadnaviruses so far, DCH infection has been associated with hepatic disease in its host. Prevalence of this infection in the United States has not been explored broadly. Thus, we utilized conventional and quantitative PCR to screen several populations of domestic cats to estimate DCH prevalence in the United States. We detected DCH DNA in 1 out of 496 animals (0.2%) in the U.S. cohort. In contrast, we detected circulating DCH DNA in 7 positive animals from a cohort of 67 domestic cats from Australia (10.4%), consistent with previous studies. The complete consensus genome of the U.S. DCH isolate was sequenced by Sanger sequencing with overlapping PCR products. An in-frame deletion of 157 bp was identified in the N-terminus of the core open reading frame. The deletion begins at the direct repeat 1 sequence (i.e., the 5′ end of the expected double-stranded linear DNA form), consistent with covalently closed circular DNA resultant from illegitimate recombination described in other hepadnaviruses. Comparative genome sequence analysis indicated that the closest described relatives of the U.S. DCH isolate are those previously isolated in Italy. Motif analysis supports DCH using NTCP as an entry receptor, similar to human HBV. Our work indicates that chronic DCH prevalence in the U.S. is likely low compared to other countries.

No abstract

Long-term care facilities (LTCFs) have been disproportionately impacted by COVID-19 due to their communal nature and high-risk profile of residents. LTCF staff have the ability to introduce SARS-CoV-2 into the facility, where it can spread, causing outbreaks.