1 Introduction
The coronavirus disease (COVID-19) outbreak starting in 2019 was
declared as public health emergency by the World Health Organization
(WHO) on January 30, 2020, infecting more than 16.5 million people and
continuing to spread throughout the world (WHO 1a, 2020; WHO 1b, 2020).
The disease COVID-19 was first described in Wuhan, China, in patients
that had respiratory tract infection and pneumonia (Zhou et al., 2020;
Andersen et al., 2020). It is caused by a novel betacoronavirus known as
severe acute respiratory syndrome virus 2 (SARS-CoV-2) that is
genetically related to bat coronavirus RaTG13 and other
betacoronaviruses that are found in bats (Zhou et al., 2020; Andersen et
al., 2020; Lu et al., 2020).
Viruses in the coronavirus family are enveloped, single stranded
positive sense RNA viruses with genomes ranging between 26 to 32 kb (Su
et al., 2016; Fehr et al., 2015). The coronavirus family contains a wide
range of viruses that are pathogenic to a variety of animal species
including humans. However, many of these viruses tend to have limited
host range and can cause severe diseases only in domestic animals,
resulting in large production losses to producers. Some animal
coronaviruses such as transmissible gastroenteritis virus (TGEV), bovine
coronavirus (BCoV), feline coronavirus, canine coronavirus and turkey
coronavirus cause enteritis in their respective hosts (Su et al., 2016).
Others such as avian infectious bronchitis and canine respiratory
coronavirus cause respiratory diseases in their respective hosts (Su et
al., 2016).
Prior to 2003, viruses of the coronavirus family were not known to cause
severe disease in humans. However, since the beginning of the
21st century three viruses from the betacoronavirus
subfamily, Severe Acute Respiratory Syndrome virus (SARS), Middle
Eastern Respiratory Syndrome virus (MERS) and SARS-Cov-2 have crossed
the species barrier to infect humans (Kin et al., 2015; Peiris et al.,
2003; Zhou et al., 2020).
When a novel virus results in an outbreak or pandemic, assessing the
risk of the novel agent to infect other species is of paramount
importance in order to control the disease. Since the emergence of
SARS-CoV-2, a number of studies have been conducted as part of the risk
assessment to determine if domestic animals that are used as companion
animals in households or as source of food are susceptible to the virus.
Additional studies were also conducted in laboratory animals such as
mice, ferrets, non-human primates and others in search of animal models
that could be used to study virus pathogenesis, vaccine efficacy studies
and prophylaxis of the disease.
The purpose of this study was to determine if domestic poultry such as
turkeys and chickens are susceptible to SARS-CoV-2 virus and play any
potential role in the dissemination of the virus. In addition, the
susceptibly of chicken embryos to SARS-CoV-2 was evaluated to determine
if eggs could potentially be used for the production of potential
SARS-CoV-2 vaccines.