1.
COVID-19: A Zoonosis
~60% of all known infectious diseases, and ~ 75% of
emerging infectious diseases are zoonotic (UNEP).
BR Singh
Pri. Scientist and Head
R. Karthikeyan & Akanksha Yadav
Ph.D. Scholars
Division of Epidemiology
ICAR-IVRI, Izatnagar-243122
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2.
Zoonoses
• Zoonosis: The disease communicable from an
animal/ birds to a human with or without making
animal/ birds sick.
• Reverse zoonosis (zooanthroponosis, or
anthroponosis), Pathogens of humans that are
capable of being transmitted to other non-human
hosts.
• Phytozoonosis: Diseases of plants transmissible
between plants and man (phytonoses)
e.g., human uveitis mycoplasma-like organisms
(MLO).
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3.
COVID-19
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4.
Origin of Severe Acute Respiratory Syndrome
Corona Virus-2 (SARS-CoV-2) and COVID-19
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• Natural selection in an animal host before
zoonotic transfer
• Natural selection in humans following
zoonotic transfer
• Conspiracy theory, laboratory synthesized
virus (bio-weapon).

5.
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• Instability of the replicase enzyme,
• RNA dependent RNA polymerase,
• Polybasic furin cleavage site, and
• O-linked glycans,
• Lack of proofreading mechanism,
• A higher rate of mutations in the RBD of spike
gene and
• Genetic recombination
The emergence of novel CoVs and
their wide host range

6.
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• Human-Human
• Human-Mink-Human
• Angiotensin-converting enzyme-2 (ACE-2)
receptors for SARS-CoV-2.
• Protein modelling indicated presence ACE-2 in
civets, pigs, ferrets, cats, dogs, pangolins, Chinese
hamester, orangutans, monkeys, bat species, and
humans with similar levels of affinity for SARS-
CoV-2 while pangolins ACE-2 had much better
affinity than human ACE-2.
COVID Zoonosis

7.
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COVID-19, a reverse zoonosis
Type of animal Date Country
Dog 11-7-20 (11-4-20) USA
Tiger 06.04.2020 USA
Lion 17.04.2020 USA
Cat USA
Cat 28.07.2020 UK
Mink 17.06.2020 Denmark
Cat 26.05.2020 Russia
Cat 13.05.2020 Germany
Cat 11.05.2020 Spain
Cat 08.06.2020 Spain
Cat 02.05.2020 France
Cat 12.05.2020 France
Mink 26.04.2020 The Netherlands
Cat 28.03.2020 Belgium
Hong Kong 09.03.2020 Dogs

8.
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• Ban on legal and illegal trade of wild/game animals, their meat
and other products.
The UN (2020):10 steps.
• 1. Raising awareness
• 2. Governance to increase investments in interdisciplinary
approaches including the One Health perspective
• 3. Promoting scientific enquiry attitude
• 4. Financial strengthening
• 5. Monitoring and regulation of Zoonotic infectuions
• 6. Incentives
• 7. Biosecurity and control
• 8. Agriculture and wildlife habitats protection
• 9. Capacity building in one health (environmental health)
• 10. Operationalizing the one health approach
Prevention of emergence of Zoonosis like
COVID-19

9.
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• COVID-19 is certainly a newly emerged zoonosis, not
yet understood properly thus cases need utmost care
in its handling in both in human and animals.
• More observations and studies can only elucidate the
origin, intermediate host and definitive host (till date
humans) and maintenance host of SARS CoV-2.
• For control of emerging and re-emerging zoonoses
potentiating one health environmental approach for
understanding disease drivers and control strategies
are essential elements.
Conclusion

10.
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