CORONA VIRUS

2. Coronaviruses are large, enveloped RNA viruses
The human coronaviruses cause common colds, may cause lower
respiratory tract infections, and have been implicated in gastroenteritis in
infants.
A novel coronavirus was identified as the cause of a worldwide outbreak of
a severe acute respiratory syndrome (SARS) in 2003
Animal coronaviruses cause diseases of economic importance in domestic
animals.
Coronaviruses of lower animals establish persistent infections in their
natural hosts.
The human viruses are difficult to culture and therefore are more poorly
characterized.

3. Human coronavirus OC43. Note the characteristic
large, widely spaced spikes that form a “corona”
around the virion

4.  Virion: Spherical, 120–160 nm in diameter, helical nucleocapsid
 genome: Single-stranded RNA, linear, non - segmented, positive-
sense,27–32 kb, capped and polyadenylated, infectious
 Proteins: Two glycoproteins and one phosphoprotein. Some viruses
contain a third glycoprotein (hemagglutinin esterase)
 envelope: Contains large, widely spaced, club- or petal-shaped spikes
 Replication: Cytoplasm; particles mature by budding into endoplasmic
reticulum and Golgi
 Outstanding characteristics:
 Cause colds and SARS
 Display high frequency of recombination
 Difficult to grow in cell culture

5. Human coronaviruses do not grow well in cell culture , details of viral
replication have come from studies with mouse hepatitis virus, which is
closely related to human strain OC43.
The replication cycle takes place in the cytoplasm of cells.
entry to the cell the virus particle is uncoated and the RNA genome is
deposited into the cytoplasm.
Coronavirus have single positive strand RNA genome, they can directly
produce their protein and new genome in the cytoplasm.
The Coronavirus genome has a 5’ methylated cap and a 3’polyadenylated
tail. This allows the RNA to attach to ribosomes for translation.

6. The protein N binds genomic RNA and the protein M is
integrated into the membrane of the endoplasmic
reticular(ER), protein S after binding, assembled nucleo-
capsids with helical twisted RNA budding into the ER lumen
and are encased with membrane.
These viral progeny are finally transported by Golgi vesicles
to the cell membrane and exocytosis.

7. Coronavirus replication cycle.

8. Coronaviruses primarily infect the upper respiratory and gastrointestinal
tract.
SARS coronavirus also infects epithelial cells lining salivary gland ducts
(shown in monkeys).
Coronavirus infections in humans usually, but not always, remain limited to
the upper respiratory tract.
SARS serious respiratory illness, including pneumonia and progressive
respiratory failure.
Virus can also be detected in other organs, including kidney, liver, and
small intestine , and in stool.

9. The SARS virus probably originated in a nonhuman host, most likely bats,
was amplified in palm civets, and was transmitted to humans in live animal
markets.
Coronaviruses are suspected of causing some gastroenteritis in humans

10. Produce “colds,” usually afebrile , in adults.
The symptoms are similar to those produced by rhinoviruses, typified by
nasal discharge and malaise.
Incubation period is from 2 to 5 days, and symptoms usually last about 1
week.
SARS coronavirus causes severe respiratory disease.
The incubation period averages about 6 days.
symptoms include fever, malaise, chills, headache, dizziness, cough, and
sore throat, followed a few days later by shortness of breath.

11. ELISA
PCR

12. no proven treatment for coronavirus infections and no
vaccine.
Protease inhibitors used in the treatment of human
immunodeficiency virus infections (eg, lopinavir) have in vitro
activity against SARS coronavirus.
SARS vaccines are under development

13. Control measures that were effective in stopping the spread
of SARS included isolation of patients, quarantine of those
who had been exposed, and travel restrictions.
Use of gloves, gowns, goggles, and respirators by health
care workers.

14.  THANK YOU