الفهرس 
Title : Investigation of spillover evidence of SARS-CoV-2 virus in dogs and cats in Egypt
AbstractOnly 14 pages are availabe for public view
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Abstract
SARS-CoV-2 zoonotic and reverse zoonotic transmission could be
resulted from routine activities and interactions between humans and their
companion animals. A combination of SARS-CoV-2 high mutation rate and
homology of cellular ACE2 receptors enable SARS-CoV-2 to transcend
species barriers and facilitate the viral transmission between humans and
animals. The aim of this study to investigate spillover of SARS-CoV-2
between humans and companion animals with studying mutations of the
detected SARS-CoV-2 spike glycoprotein and the effect of these mutations on
the viral structure and function.
Oropharyngeal/Nasopharyngeal swabs, serum and blood samples were
collected form 66 companion animals (33 cats and 33 dogs) which were close
contact to SARS-CoV-2 positive owners from December 2020 to March 2021.
Swabs were screened by rRT-PCR and some positive cases were confirmed by
partial spike sequencing. Clinical pathology and pathological studies were also
performed. Spillover of SARS-CoV-2 between humans and their companion
animals were reported in Egypt with a rate of 30.3% of cats (10/33) and 24%
of dogs (8/33) by using rRT-PCR. Partial spike gene sequencing of 6 positive
samples collected in December 2020 were identical to SARS-CoV-2 that was
detected in humans in Egypt in that time frame. Furthermore, the infected
companion animals have suffered from lymphocytopenia, thrombocytopenia
with elevation of ferritin, LDH, C-reactive protein and D-dimers levels. The
latter infected animals have showed a wide range of clinical signs including
asymptomatic, mild and severe respiratory signs with some deaths in the
infected cats. The dead cats exhibited multiple systematic pathological lesions
in lung, heart, liver intestine and kidney. Thus, spillover of SARS-CoV-2 may
be occurred between humans and pet animals.
Full spike sequencing for some detected SARS-CoV-2 in cats that were
collected in December 2020, March 2021 and July 2021 has displayed 7 amino
acid substitutions. Structural modelling has revealed that 4 of these mutations
could affect the interaction with the neutralizing antibodies and others could
influence S1/S2 cleavage, facilitate viral binding to the ACE2 host receptors
and enhance viral infectivity. Bioinformatics analysis of ACE2 receptors in
different animal hosts has provided in-depth investigation for RBD/ACE2
complex binding affinity and their relationship to SARS-CoV-2 infection
susceptibility. Therefore, this thesis paves the way for studying SARS-CoV-2
host susceptibility in different animal species.