Lecture 1 General Virology B&W

8/3/2019 Lecture 1 General Virology B&W

1/35

Introduction to GeneralVirology

Presented by:

Prof. Dr. Mervat El Saygh

Microbiology & Medical Immunology Dept,Pharos University

Lecture 1


2/35

Thursday 13/10/2011 2Dr. Mervat Elsaygh- Pharos University

Course Specification

Lecture 2

Practical ...

Tutorial 1

No. of Instructional Units:

2 CrsSpecialization:

General

Department of

Microbiology

Academic Year/ Level:

Junior 2011/2012 ( level 5)

Course Title:

Virology

Course Code:

PHR 563


3/35



c1- Distinguish the viral infections

c2- Analysis by PCR

c3- Perform serology

c4- Preparation of viral vaccines

c- ProfessionalSkills

b1-Construct and apply the laboratory diagnosis, mechanism of infection,

disease transmission and treatment of some viral diseases

b2- Discover and report the different laboratory results and relate them withthe clinical picture to be able to establish a diagnosis.

b-IntellectualSkills

a1-Identify and describe the members of the viral world Tabulate the

differences between bacteria and viruses

a2-Identify, describe, name and label viral structure Describe and explain

replication of virusesa3-Identify and distinguish viruses causing diseases

Identify and interpret the signs and symptoms of some viral diseases.

a-KnowledgeandUnderstanding

3-Intended Learning Outcome: By the end of this course , student will be able to:

a. Recognize structural components of the viruses and how they influence

pathogenesis of the disease and how they are transmitted among individualsand populations

b. Develop the ability to correlate the clinical picture with laboratory

information to establish a diagnosis.

c. Students will be able to become abreast or emerging viral diseases and

the challenges they pose that assist the pharmaceutical industry....

2-Course Aim


4/35



General features of viruses. Viral replications. Classification of viruses

Bacteriophage.Antiviral chemotherapy. Viral vaccines. Interferon.

Laboratory diagnosis of viral infections. I-DNA viruses:

Herpes viruses. Papillomaviruses.

Adenoviruses.

II-Hepatitis viruses.

Ill-RNA viruses:Picornaviruses.

Orthomyxoviruses. Paramyxoviruses.

Rhabdoviruses. Retroviruses (HI V/AIDS)....

4-CourseContent

d1-Verify the different characteristics and morphology of viruses causinginfection depending on their morphology

d2-Propose ways in order to prevent and guard against different infections

by viruses. Sketch microscopic appearance of viruses

d3-Practice the ability to communicate with others and work within a group

d4-Practice the ability to prepare certain topics of the course and be able toextract information from text, reference books and the internet

d5- Practice the ability to develop the good performance for oral

presentations.....

d-General Skills


5/35



Course Work 50 %

Final exam 50%

c-Weighing ofAssessment:

Quizzes: weeks 6 and 12 andAssignemnts: week 7

final exam: weeks 16 and 1 7

b-Schedule:

Written exam

Assignments

Quizzes

a-Proceduresused:

7-Student Assessment:

6-Teaching and Learning Methods for Students w ith SpecialNeeds

None

Lectures

Demonstration of more detailed information by Power

point projection

. -Tutorial

-Group presentation

-Self learning assignments

-Quizzes

5-Teaching

and LearningMethods


6/35



www.virology.net

www.elsevier.com/locate/yviro

d- Periodicals,

Web Sites, ..., etc.

IS ButeL SA Morse, 2004, Medical Microbiology. Twenty-third edition by .IF Brooks LANGE Medical Books.

c-RecommendedBooks

- GJ Tortora, BR Funke, CL Case, 2010, Microbiology, an

introduction. Ninth edition by. Pearson Education, Inc.

- RA Harvey, PL Champe, BD Fisher L, 2007, Lippincot's

Illustrated Reviews: Microbiology. 2nd Edition by.

Lippincott's Williams and Wilkins

b- Required Books

(Textbooks)

Available in the faculty web sitea-Course Notes

8-List of References:

Course Instructor: Prof. Dr. Mervat ElsayghDr. Rania AboZahra

Head of Department: Prof.Dr. Hoda Elshamy


7/35


OUTLINE

Definition of the viruses

Classification and types

Structure and shape

Mode of transmission and replication

Diseases caused by the viruses

Gallery


8/35


GENERAL FEATURES OF

VIRUSES

Size: very small in size is measured by nm

which is 10-9meter or 10-3micrometer.It needs

electron microscope to be detected.

Obligate intracellular parasite Contain either DNA or RNA never both.

Can affect humans, animals, insects, bacteria

and plants.

They do not respond to any antibiotic.


9/35


STRUCTURE OF THE VIRUSES

Genome: the viral nucleic acid carries the

genetic information in either DNA or RNA

which is considered as the finger prints of

the virus. Capsid (Protein coat): is the protein shell

which enclose the nucleic acid. It is formed

of small units called capsomeres.


10/35




11/35



1- It protects the viral genome against

extracellular environments.

2- It carries the viral attachment proteins (VAP)

which are glycoproteinsthat attach the virus

to a specific receptor on the target cell.

3- Determine the antigenic characters of the

virus.4- It is responsible for the symmetry of the

virus.


12/35


VIRAL SYMMETRY1. Cubic or icosahedralsymmetry e.g.

Herpes viruses.


13/35


VIRAL SYMMETRY2- Helical symmetry: the

capsomeresare boundtogether as ribbons which

are twisted into spiral. The

NA winds in a helical form

inside the protein helix e.g.

Influenza virus.

3- Complex symmetry e.g.

Small pox


14/35


The Shape of the Virus

The shape of the virus vary, may be:

Spherical

Filamentous

Bullet shape


15/35


ENVELOPE It is a protein containing a

lipid membrane that

surrounds the capsidin

some viruses. Here theVAP is carried and present

on the envelope. The

enveloped viruses arekilled by lipid solvents e.g.

ether


16/35


THE EFFECT OF PHYSICAL AND

CHEMICAL AGENTS

Viruses are sensitive to:

1- UV: Ultraviolet irradiation.

2- Ether: only the enveloped viruses are sensitive to

ether.

3- Oxidizing agents: as formaldehyde, CL, I2and H2O2

4- Sensitivity to heat:

- Most viruses are inactivated at 56C for 30 min orat 100C for few seconds

- Viruses are stable at low temp, can be stored at -

40C -70C.


17/35


Most viruses are relatively resistant to:

Phenols and glycerol, therefore sometimes

glycerol is used as preservative to prevent

bacterial contamination of viral suspensions


18/35


CLASSIFICATION OF VIRUSES DNA Viruses

Most are double stranded All are icosahedralexcept small pox virus.

Most are none enveloped except Herpesv and

hepatitis B virus. RNA Viruses

Most are Helical and all the helical are enveloped.

Some are enveloped icosahedralas the HIVand theGerman measles v, while Polio and hepatitis C arenaked


19/35


Classification By

Symptomatology

1- Diseases of the respiratory tract: influenza,

parainfluenzaand common cold.

2- Diseases of the nervous system: poliomyelitis,

aseptic meningitis and rabies.

3- Localized disease of the skin or mucous

membrane: Herpes simplex type 1 (oral) andtype 2 (genital) and wart.


20/35


Classification By

Symptomatology

4- Diseases of the liver: Hepatitis A E

5- Diseases of the eye: Herpesconjunctivitis

6- Diseases of the GIT: rotavirus diarrhea, enteric

adenoviruses

7- Diseases of the genital tract: HSV 2, HIV


21/35


Viruses ReplicationViruses are obligatory intracellular as they

are metabolically inert. After invading a

cell, viruses use their own genes to

redirect the machinery of the cell toproduce new viruses; this is done by virus

messenger RNA.


22/35


VIRUS GROWTH CYCLE1. Adsorption ,

2. Penetration,

3. Uncoating,

4. Transcription or eclipse phase,

5. Assembly

6. ReleaseRecognition and attachment to the target cell (by VAP)

occurs by special receptors on the host cell


23/35


VIRUS GROWTH CYCLE


24/35


Eclipse phase or transcriptionTranscription leads to formation ofproteins

as polymerase enzyme, virus specific

antigens and then capsidis formed (no

intact viruses are detected)


25/35


AssemblyIt is combination of the viral nucleic acid with the

protein coat


26/35


ReleaseEither by lysisof the cell in the none enveloped viruses or by

budding from the cell membrane where the envelope is

acquired from this membrane


27/35


Host Response To Viral Infection

1- Humoral immune response

Antibody response to neutralize and eliminate the

ongoing Infection and can also prevent reinfection.

2- Cell mediated immune response

Stimulate the production of lymphokinesas Interferon

swhich is very important for defense against viruses


28/35


Interferon

Are proteins produced by human cells in

response to viral infection.


29/35


Properties1. Are the first line of body defense against viral infection.

2. It inhibit sviral replication.

3. Host species specific.

4. Not viral specific.

5. It acts also as cell immune regulatory activity asactivation of natural killer cells, activation of

monocytesand macrophages and inhibition of cell

growth.

6. Recombinant DNA techniques now allow production of

inexpensive large amount of interferon by yeast and

bacteria.


30/35


CLINICAL USES Used in treatment of sever viral infection

e.g. rabies, herpetic encephalitis,.etc

In the treatment of persistent viral

infections e.g. hepatitis B & C,etc Used as anticancer agent on the basis of

their cell immunomodulation properties. Treatment of multiple sclerosis.


31/35


Gallery


32/35


Gallery


33/35


Gallery


34/35


Homework Questions Define:

Interferon,

Its Clinical uses,

& its properties

Mention the 6 steps of viruses replication.

Classify viruses by Symptomatology


35/35

Thank You

Documents

Lecture 1 General Virology B&W