Life cycle , prevention as well as pathogenicity

1. Coronavirus Disease (COVID- 19)
Mr. Saurabh S. Kedar, Mr. Shubham S. Tupe
Guide : Prerana B. Abhang
© SS2020

2. Contents
• Introduction
• Symptoms
• Who Can affected the
most?
• Spread thorough
• Structure and Replication
• Pathogenesis
• Screening/ Laboratory
Analysis
• Treatments
© SS2020

3. Introduction
1.Coronaviruses are a group of large, enveloped, positive-
sense, single-stranded RNA viruses belonging to the order
Nidovirales, family Coronaviridae, subfamily
Coronavirinae. Twenty-six different species are known
(Cleri, D.J. et al 2010) and have been divided into four
genera (alpha, beta, gamma and delta) characterized by
different antigenic cross-reactivity and genetic makeup.
Only the alpha- and betacoronavirus genera include strains
pathogenic to humans (Paules, C.I. et al 2020).
2.Coronaviruses have long been recognized as important
veterinary pathogens, causing respiratory and enteric
diseases in mammals as well as in birds. Of the known
coronavirus species, only six have been known to cause
disease in humans: HCoV-229E, HCoV-OC43, HCoV-
NL63, HCoV-HKU1, severe acute respiratory syndrome
coronavirus (SARS-CoV) and Middle East respiratory
virus coronavirus (MERS-CoV) (Arabi, Y.M. et al (2017);
Skariyachan, S. et al (2019).© SS2020

4. 5. Coronaviruses have been present in humans for at least
500-800 years, and all originated in bats (Chan, P.K. et al
(2013); Berry, M. et al (2015)
6.High prevalence and wide distribution of coronaviruses,
their large genetic diversity as well as the frequent
recombination of their genomes, and increasing activity at
the human animal interface, these viruses represent an
ongoing threat to human health (Hui, D.S. et al (2020)
7. The virus, provisionally designated 2019-nCoV, was
isolated and the viral genome sequenced. 2019-nCoV was
characterized as a betacoronavirus, and thus became the
seventh discrete coronavirus species capable of causing
human disease
© SS2020

5. Symptoms
• Fever
• Tiredness
• Dry cough
• Nasal congestion
• Runny nose
• Sore throat
• Diarrhea
• Difficulty breathing
© SS2020

6. Who Can affected the most?
• Immuno compromised
individuals
• Chronic Disorders :
1. Bronchial Asthma
2. Diabetes
3. Cardiovascular patients
• Old Age people, Malignancy
© SS2020

7. Spread thorough
• Droplet infection (Cough &Sneeze)
• Surfaces (Table, desks etc.)
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8. 1. Coronaviruses are so named because of their characteristic solar corona
(crown-like) appearance when observed under an electron microscope. This
appearance is produced by the peplomers of the spike [S] glycoprotein
radiating from the virus lipid envelope (Chan, J.F. et al 2015)
2. There are two major envelope proteins. The S glycoprotein is a major
antigen responsible for both receptor binding and cell fusion (Song, Z. et al
2019)and the transmembrane glycoprotein [M] is involved in budding and
envelope formation; the M protein has also been found to play a pivotal role
in virion assembly (Tseng, Y.T. et al 2010).
3. . The viral genome is associated with the basic phosphoprotein [N] within
the capsid. The genome is non segmented, positive single-stranded RNA of
about 26-32 kb, making it the longest RNA viral genome known, and
contains from 7 to 10 different open reading frames.
Structure and Replication
© SS2020

9. 4. The RNA molecule has a methylated cap in 5' and a poly-A tail in 3'
(Kilianski, A. et al (2014); Song, Z. et al 2019).
5. Coronaviruses are capable of adapting quickly to new hosts through
the processes of genetic recombination and mutation in vivo.
6. As RNA viruses, coronaviruses rely on RNA-dependent RNA
polymerase (RdRp) to replicate the virus genome.
7. when the same host is simultaneously infected with two coronavirus
strains, enabling recombination. One coronavirus can gain a genomic
fragment of hundreds or thousands base-pair long from another CoV
strain when the two co-infect the same host, enabling the virus to
increase its ecological niche or to make the leap to a new species
(Chan, P.K. et al 2013; Raj, V.S. et al 2014).
8. This susceptibility enabled the emergence in approximately two
decades of three new human coronavirus species with epidemic
potential: SARS-CoV, MERSCoV and 2019-nCoV.© SS2020

10. Pathogenesis
• It causes both upper and lower respiratory tract infection
Virus attaches to specific cellular receptor via the spike protein.
Transformational changes leading to fusion between the viral
and cell membrane.
Release of nucliocapsid into the cell
Alteration of DNA and production of proteins and certain
specific enzymes
© SS2020

11. Alteration of cell function and production
Release of excess cytokines & chemokine's (IL-Iβ, IL-ϭ)
Increase acute phase reactant (ESR,CRP)
Cause of death due to complications/ Effect caused by cytokine storm
syndrome, Severe Acute Respiratory distress syndrome
Fulminant Myocarditis
Hyper inflammation
© SS2020

12.  WBC Count may vary
 Decreased lymphopenia count
 Increased LDH level (Due to affinity of cytokines for chronic tissue
 Virus confirmed by RT-PCR technique
Screening/ Laboratory Analysis
© SS2020

13. Treatments
 Nothing has been postulated officially
 Hospitalization only for severe cases
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14. Supportive treatment
 Maintain airway, Breathing, Circulation
 Ventilation if required
 Isolation (To avoid spread)
 Correct temperature
© SS2020

15. Sources
• https://www.who.int/
• Coronaviruses - Drug discovery and
therapeutic options Azhar, E.I.
• Host cell proteases: Critical determinants of
coronavirus tropism and pathogenesis
• Coronaviruses post-SARS: Update on
replication and pathogenesis Perlman, S.
• Coronavirus infections-More than just the
common cold Paules, C.I.;Marston,
H.D.;Fauci, A.S.
© SS2020

16. Thank You
© SS2020