Pod1 –pbl4

Asem shadid

Objectives:

1–Describe the morphology and structure of virus A/H1N1?

2-Describe the clinical features A/H1N1?

3-Describe the pathology and immune response of A/H1N1?

4-Describe the transmission and prevention of A/H1N1?

5-list the diagnostic tests A/H1N1?

Objectives:

DEFINITION OF A VIRUS

• a single nucleic acid surrounded by a protein coat and capable of replication only within the living cells of bacteria, animals or plants.

• A VIRUS is either DNA or RNA, that is protected by a protein coat called a

CAPSID.

• Viruses cause colds, flu, warts and diseases such as measles,

AIDS and cancer.

• BUT not all viruses cause

diseases,

• AND not all viruses are

harmful to humans.

VIRUS

DNA CAPSID

LET’S LOOK AT THE DEFINING PROPERTIES OF VIRUSES

• Viruses are parasites that invade cells• Viruses have either DNA (Deoxyribose Nucleic Acid) or RNA

(Ribonucleic Acid)• Viruses direct the synthesis of new virus within a host cell.• Newly made viruses infect other cells.

WHY ARE SOME VIRUSES HARMFUL?

Virus invades cell

Virus forces cell to make copies of virus

Eventually so many copies are

made, the cell explodes,

releasing all of the new viruses

• When your cells make viruses instead of

operating normally, YOU get sick

1–DESCRIBE THE MORPHOLOGY AND STRUCTURE OF VIRUS A/H1N1?

Influenza A (H1N1) virus

• Influenza hemagglutinin (HA) is a

glycoprotein found on the surface of the influenza viruses. It is responsible for binding the virus to

cells with sialic acid on the

membranes

• Neuraminidases are

enzymes that cleave sialic

acid groups from

glycoproteins and are

required for influenza virus

replication.

• Viral neuraminidase is a type

of neuraminidase found on

the surface of influenza viruses that enables the virus

to be released from the host

cell.

The three main types of influeza viruses

known to infect humans are

influenzavirus A, B and C. Of these

three types influenza virus A is common

and endemic to pigs. This means that

the influenza virus A commonly infects

both humans and pigs.

• Influenza A (H1N1) virus is the subtype of influenza A virus that was the most common cause of human influenza (flu) in 2009.

• Neuraminidase are a type of

glycoside hydrolase enzyme which help to move the virus

particles through the infected

cell and assist in budding from the host cells.

• Haemagglutinin causes red

blood cells to clump together and binds the virus

to the infected cell.

2-DESCRIBE THE CLINICAL FEATURES A/H1N1?

3-DESCRIBE THE PATHOLOGY AND

IMMUNE RESPONSE OF A/H1N1?

4-DESCRIBE THE TRANSMISSION AND PREVENTION OF A/H1N1?

HOW DOES THE 2009 H1N1 VIRUS SPREAD?

• Spread of the 2009 H1N1 virus is thought to occur in the

same way that seasonal flu spreads.

• Flu viruses are spread mainly from person to person

through coughing, sneezing or talking by people with

influenza.

• Sometimes people may become infected by touching

something – such as a surface or object – with flu

viruses on it and then touching their mouth or nose.

5-LIST THE DIAGNOSTIC TESTS A/H1N1?

It's hard to tell whether you have swine flu or seasonal flu, because most symptoms are the same.

People with swine flu may be more likely to feel nauseous and throw up

than people who have seasonal flu.

A number of flu tests are available to detect influenza viruses.

The most common are called “rapid influenza diagnostic tests” that can

be used in outpatient settings. These tests can provide results in 30 minutes or less. Unfortunately, the ability of these tests to detect the flu

can vary greatly.

Diagnostic testing is recommended on suspect cases of novel influenza

A H1N1(swine flu). Active infection with swine influenza can only be confirmed by polymerase chain reaction (PCR) assays.

ASEM SHADID

THANK YOU