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Question 1

What are the main types of virus structures?

Answer 1

Either DNA or RNAandeither single or double stranded

Question 2

How do viruses replicate inside host cells?

Answer 2

Viral cell binds to host cell by CD4 receptor where is it then taken up into the cell by endocytosis. Uncoating occurs and the virus is removed from its envelope by specific cellular enzymes. Replication of the viral genom occurs using the host cells replication machinery. Once the genetic material has been synthesised, it is put into a virion and the virions are then released.

Question 3

What investigations give an indication of viral infection?

Answer 3

Rise in antibody levels- first IgM and then IgGPCR - primers can be used to detect specific viruses and

Question 4

What are some general features of BBV?

Answer 4

Likely to have more than oneTransmitted via blood products or sexPrevention is a big issueHave significant morbidity and mortality if untreatedOften have no cure and aim is to suppress the virus

Question 5

Give the physical characteristics of HIV

Answer 5

Single stranded RNA virusHave two different strains, HIV1 and HIV2

Question 6

How is HIV transmitted?

Answer 6

SexInjecting dug use with contaminated needlesMother to infantContaminated blood tissue products

Question 7

How does HIV get inside cells?

Answer 7

Attaches to CH4 cells and reverse transcriptase makes DNA from RNA which is then integrated into the host cell nucleus and undergoes reproduction. The new HIV viruses are assembled and are released

Question 8

What is an important measure for HIV?

Answer 8

CD4 lymphocyte count

Question 9

What is acute disease syndrome?

Answer 9

High amount of virus replication is occurring, so there is a high amount of virus and capsid protein present in the blood. Lymph nodes become infected and serve as the sites of persistence during the asymptomatic period. - don’t produce antibodies at this point

Question 10

What are the symptoms of acute disease syndrome?

Answer 10

Feverrashflu-like symptomsweight losspharyngitisgeneralised lymphadenopathy

Question 11

How can you diagnose HIV?

Answer 11

Check the viral loadImmunoblotResistance profileCD4 levels - determine course of treatment Antibody level

Question 12

What is the treatment for HIV?

Answer 12

1. HAART (highly active antiretroviral therapy)Three main drugs which have an effect on different parts of the cycle for HIV– attachment inhibitors– fusion inhibitors– protease inhibitors2. 
Prophylaxis against opportunistic infection

Question 13

What is post-exposure prophylaxis?

Answer 13

Give antiretrovirals to someone who may have come into contact with contaminated blood

Question 14

What are the physical characteristics of hepatitis B?

Answer 14

Double stranded DNA type divided into genotypes A-D (determines treatments and outcomes)

Question 15

What are the features and symptoms of acute hep B?

Answer 15

Huge increase in viral loadMild fevermalaiseanorexiamyalgianauseaclubbing of fingersascitesCAN BE ASYMPTOMATIC

Question 16

What are the features of chronic hep B?

Answer 16

Can lead to cirrhosis —> liver cancer/liver failure

Question 17

What is the treatment for hep B?

Answer 17

Antiviral drugs – are suppressive rather than curative– tend to use single drugs

Question 18

What are some prevention methods of hepatitis B?

Answer 18

Have a vaccinationPost exposure prophylaxis

Question 19

What are some investigations that can diagnose hepatitis B/

Answer 19

Liver functionDetect antibody and antigen levels in the blood

Question 20

What are the different antigen proteins that can be detected in the blood?

Answer 20

HBeAg —> indicates highly infectiousHBsAg —> found on surface of antigen, most likely to be seen firstHBcAg —> found in core of the antigen

Question 21

Describe the physical characteristics of hepatitis C

Answer 21

Single stranded RNA flavovirus

Question 22

What is the main transmission method of hepatitis C?

Answer 22

Mainly due to infected drug useSome from sex

Question 23

What are some specific characteristics of the development of hepatitis C?

Answer 23

High chance to going onto develop a chronic infection but it is very slow to progress and often asymptomatic Cure is possible - 40-80% however with significant side effects

Question 24

What are the investigations used for hepatitis C?

Answer 24

1. Viral loading occurs so look for increased HBsAg and HBeAg antigens in the acute phase 2. Elevated liver enzymes in serum3. Increased HBcAg antibodies which rise with liver enzyme levels

Question 25

What is the treatment for hepatitis C?

Answer 25

Monitor viral loadDecide when to give antiretroviralsMonitor side effects of antiretroviralsPrevent other liver disease

Question 26

What is a major issue if someone does not adhere to their drug regimen?

Answer 26

The virus may become resistant to the drugs that the patent is taking sporadically. This can be useful when someone has become exposed or possibly infected as you need to identify which drugs may be the best to give that person so that they do not develop the viral infection.