Corona virus COVID19

Corona virus
Corona virus disease 2019
(COVID-19)
Dr. Harinatha Reddy, M.Sc, Ph.D.
Department of Microbiology

Introduction:
 COVID-19 causes acute respiratory
syndrome.
 The first case was reported in Wuhan,
China in December, 2019.
 The disease spread worldwide, and
became pandemic.
Dr.Harinatha Reddy, MSc, Ph.D.

Where and when was the Covid19 first
detected?
The virus first detected at "wet market" in Wuhan, Hubei
province, in December, 2019
The experts now believe the COVID19 may simply have
been amplified there.

History of Corona virus:
 Human coronaviruses were discovered in the 1960s,
through a variety of experiments in the United States and
the United Kingdom.
 Coronaviruses are a big family of different viruses.
 Some of them cause the common cold in people.
 Others infect animals, including bats, camels, and cattle

History of Corona virus:
 The available evidence for
COVID-19 suggests that SARS-
CoV-2 has a zoonotic source
(Bats origin).
 The genomic features and fast
spreading nature of SARS-CoV-2
and have found that SARS-CoV-2
is a laboratory construct in
china.

China virologist claims she has proof virus
made in Wuhan lab:
 Dr Li Meng-Yan, a researcher at the Hong Kong School of
Public Health, had previously accused Beijing of covering
up the outbreak in Wuhan….

China secrecy has made coronavirus crisis much
worse..
• Could China’s response have
worked better?
• In the initial weeks of the
outbreak in December and
January, Wuhan authorities were
slow to report cases of the
mysterious infection.
• The delay of China to act is
probably responsible for this
world pandemic..

How coronavirus spread outside China in one year
 After the first case reported in
Wuhan, China in December, 2019, it
took weeks for Covid-19 to spread
across the globe.
 By the end of January 2020, the
virus had spread to South East Asia,
Australia, Iran, US, UK and India.
 By the end of March, almost all the
major countries of the world had
reported positive cases.

Structural proteins of Covid-19
Covid-19 virus structure

Covid-19 virus structure:
 Coronaviruses belong to family Coronaviridae.
 They are enveloped viruses with a positive-sense single-
stranded RNA genome.
 The length of the RNA genome is approximately 26 to 32
kilobases, one of the largest among RNA viruses
 Club-shaped spikes that project from their surface

 Coronaviruses spherical in shape.
 The size is highly variable with
average diameters of 80 to 120 nm.
 The extreme sizes are known from
50 to 200 nm in diameter.
 The average molecular weight is
40,000 kDa.

Structural proteins of Covid-19
 The corona viral genome encodes four major structural
proteins:
 The spike (S) protein
 Nucleocapsid (N) protein
 Membrane (M) protein
 Envelope (E) protein.
 All of which are required to produce a structurally
complete viral particle.

The spike (S) protein
 The S protein major
protein mediates
attachment of the virus
to the host cell surface
receptors such as ACE2
and TMPRSS2.
 The subsequent fusion
between the covid-19
and host cell
membranes to facilitate
viral entry into the host
cell.

The “S” protein of coronaviruses can be divided into two
important functional subunits:
 The N-terminal S1 subunit, which
forms the globular head of the “S”
protein.
 The C-terminal S2 region that
forms the stalk of the protein and
directly embedded into the viral
envelope.

Covid-19 entry in to host cell:
 A large number of glycosylated “S”
proteins cover the surface of SARS-
CoV-2.
 The ‘S’ protein bind to the host cell
receptors such as angiotensin-
converting enzyme 2 (ACE2) or
Transmembrane protease, serine
2(TMPRSS2).
 Once the virus enters the cell, the
released viral RNA is replicated, and
structural proteins are synthesized.
 Assembling of proteins around RNA
result new viral particles inside host
cell.

The E, M, N proteins of COVID19
 The ‘E’ protein is the smallest and major structural protein.
During the replication ‘E’ is abundantly expressed inside
the infected cell, but only a small portion is incorporated
into the virion envelope.
 The ‘M’ protein is the most abundant structural protein and
defines the shape of the viral envelope .
 The ‘N’ protein is the only protein that functions primarily
to bind to the COVID RNA genome, making up the
Nucleocapsid. Involves in replication cycle and the host
cellular response to viral infection

Variants of COVID19:

There are currently five variants of COVID19 (April 2021)
• B.1.1.7: This variant was initially detected in the UK.
• B.1.351: This variant was initially detected in South Africa
in December 2020.
• P.1: This variant was first detected in the US in January
2021. P.1 was initially identified in travellers from Brazil,
who were tested during routine screening at an airport in
Japan, in early January.
• B.1.427 and B.1.429: These two variants were first
identified in California in February 2021 and were classified
as VOCs in March 2021.

What causes a virus to change to a new
variant?
 All RNA viruses mutate very fast.
 When a virus is widely circulating
in a population the virus mutating
increases.
 The more opportunities a virus
has to spread, the more it
replicates – and the more
opportunities it has to undergo
changes.

Symptoms of Coronavirus
• Symptoms usually begin 2 to 14 days after you come into
contact with the virus.
 Sore throat
 Headache
 Chills
 Loss of smell
 Loss of taste
 Runny nose
 Nausea
 Vomiting
 Diarrhea

Emergency Symptoms:
Call a doctor or hospital right
away if you have one or more of
these COVID-19 symptoms:
 Trouble in breathing
 Constant pain or pressure in
your chest
 Bluish lips or face Sudden
confusion

How long does the coronavirus live
on different surfaces?

How Long Does the Coronavirus Live on Different Surfaces?
 SARS-CoV-2 showed that viruses in droplet aerosols had a
half-life of just over an hour but some could survive for
three hours or more.
 Infectious virus could be detected on:
 copper surfaces for up to 4 hours,
 on cardboard for up to 24 hours,
 on plastic and stainless steel for at least 72 hours.

Survival of Coronaviruses in Water and Wastewater
 COVID-19 hasn't been detected in drinking water.
 Covid19 die very rapidly in Wastewater, with a 99.9%
reduction in 2–3 days.

How Does Coronavirus Spread?

• COVID-19 spreads: between
people, mainly when an
infected person is in close
contact with another
person.
• The virus can spread from
an infected person’s mouth
or nose in small liquid
particles when they cough,
sneeze, speak, sing or
breathe heavily.

 Healthy people can catch COVID-19 when the
virus gets into their mouth, nose or eyes.
 Which is more likely to happen when people are in direct
or close contact (less than 1 metre apart) with an infected
person.

How long is the
incubation
period for the
coronavirus?

 Currently the incubation period for the
novel coronavirus is between 2 to 14 days
after exposure.
 More than 97 % of people who contract
SARS-CoV-2 show symptoms within 11.5
days of exposure.
 The average incubation period seems to
be around 5 days.
 For many people, COVID-19 symptoms
start as mild symptoms and gradually get
worse over a few days.

COVID-19: Who's at higher risk of
serious symptoms?

COVID-19 is more severe in people older than >60 years.
People of any age, even children, can catch COVID-19.
But it commonly affects middle-aged and older adults.

 The people of any age who have other serious health
problems such as:
 Lung problems, including asthma
 Smokers
 Heart problems,
 Weakened immune systems,
 HIV/AIDS
 Obesity,
 Diabetes,
 Pneumonia.
• Chronic kidney or liver disease etc are at higher risk.

Why men are more vulnerable to covid-19
than women?

 Females are more resistant to
infections than men, and this is
possibly mediated by several factors
such as:
 Sex hormones.
 High expression of coronavirus
receptors (ACE 2) in men.
 The life style of men such as higher
smoking and alcohol drinking.

Diagnostic testing
for the novel
COVID19.

Rapid test for COVID19
 Rapid antigen tests: Detect
viral proteins (known as
antigens) in clinical samples
are collected from the nose
and or throat with a swab.
 These tests are cheaper than
PCR and will offer results
more quickly, although they
are generally less accurate.

RT-PCR diagnostic test
 The Reverse transcriptase–
polymerase chain reaction
(RT-PCR) test: used to
identify genetic material of
COVID19 in many clinical
samples.

Preventing the spread of the
coronavirus

Preventing the spread of the coronavirus
• Cover your mouth and nose with a
mask when around others.
• Wash your hands often with plain soap
and water.
• Avoid crowds and practice social
distancing (stay at least 6 feet apart from
others).
• Get a COVID-19 vaccine.

• 70% ethanol or 90% isopropanol
• Hydrogen peroxide solutions,
• Hypochlorite bleach,
• Soaps and detergents,
• UV light
• High temperatures of cooking.
Coronavirus particles are rapidly inactivated killed by:

Is it safe to travel during COVID19 pandemic?

 Not safe travel during COVID19
pandemic, travel increases your
chances of getting and spreading
COVID-19.
 Before you get out of town, make
sure to check state and local
travel restrictions.
 Some states require out-of-state
visitors to self-quarantine.

COVID-19 vaccine
types:
Vaccines trigger an
immune response

There are four types of COVID-19 vaccines:
1. Whole virus vaccines
2. Protein subunit vaccines
3. Viral vector vaccines
4. Nucleic acid (RNA and DNA) vaccines

1. Inactivated vaccines: (Covaxin, BBIBP-CorV, CoronaVac,
WIBP-CorV and CoviVac).
2. Protein subunit vaccines: (EpiVacCorona and RBD-
Dimer).
3. Viral vector vaccines: (Sputnik-V, the Oxford–
AstraZeneca covishield vaccine , Convidecia, and the
Johnson & Johnson vaccine).
4. RNA vaccines: (Pfizer–BioNTech vaccine and the
Moderna vaccine).

COVID-19 Medications

The drugs used for the treatment of COVID-19.
 Favipiravir (antiviral drug)
 Remdesivir (antiviral drug)
 Hydroxychloroquine (Antimalarial agent)
 Tocilizumab (immunosuppressive drug)
 Steroids: Dexamethasone
 Methylprednisolone (anti-inflammatory drug)

THANK YOU
Dr. Harinatha Reddy
Aswartha
mail me@
biohari14@gmail.com

Corona virus COVID19

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