HIV, Hep B, Hep C

Question 1

What are the peripheral signs of HIV/immunocompromised?

Answer 1

Oral candidiasis, kaposi’s sarcoma, PCP: Pneumocystis carinii pneumonia

Question 2

What 3 key enzymes are involved in HIV replication within a host cell?

Answer 2

Reverse transcriptase, integrase, protease

Question 3

How is HIV transmitted?

Answer 3

Contact with large quantities of body fluids = sexual, transfusion, needles, medical procedures, perinatal transmission

Question 4

Outline the stages of the HIV viral load

Answer 4

Primary infection: very high viral load, Ab response, can present like glandular fever.

Latent: (months-years) low viral load (lower = healthier the pt) CD4 count drops with the rise in viral load.

Symptomatic infect: CD4 count <350, infections present.

Severe/AIDS: <200

Question 5

What are the main symptoms of acute HIV?

Answer 5

Fever, weight loss, pharyngitis, myalgia, hepatosplenomegaly, nausea, vomiting, rash, lymphadenopathy

Question 6

What factors affect HIV transmission?

Answer 6

Types of exposure, viral load, condom use, breaks in skin/mucosa, other infections meaning the barriers are weaker

Question 7

Outline HIV testing

Answer 7

4th generation combo assay (EIA)

• Detects Anti-HIV antibodies
• Detects p24 antigen

PCR: detects HIV nucleic acids, expensive slower, not used for screening.

Rapid: Ab, finger-prick, <1hr

Question 8

Who should be tested for HIV?

Answer 8

Everyone if rate >2/1000

Question 9

Outline HIV treatment

Answer 9

To achieve and undetectable HIV load, reconstitute CD4 count, reduce inflam, reduce risk of transmission = 3 diff ARV anti-retroviral drugs to manage the level of mutations

Question 10

How is Hep B + C transmitted?

Answer 10

B: blood, sex, vertical

C: blood, sex

Question 11

What are the symptoms of acute hep b?

Answer 11

Asymptomatic, jaundice, fatigue, abdominal pain, anorexia/nausea/vomiting

Question 12

How does Hep B serology change over time?

Answer 12

Surface Ag first, 
e-Ag, 
core Ab (IgM), 
e-Ab, 
surface Ab, 
core Ab (IgG)

Question 13

How do you know a chronic Hep B infection is present?

Answer 13

Test for surface Ag: +ve 6 months after = chronic

-ve surface Ab = not mounted good enough immune responce

Question 14

What is the treatment for Hep B?

Answer 14

No cure, life-long anti-virals but not required for inactive carriers

Question 15

Who is at risk of Hep C infection?

Answer 15

IV drug users, sexual contact, infants to HCV+ve mothers, blood transfusion prior to 1991

Question 16

What is the main diff between Hep B and Hep C?

Answer 16

Hep C = ~80% become chronically infected if untreated = liver disease, hepatocellular carcinoma, transplant, death
Hep B = vaccine

Question 17

Symptoms of Hep C?

Answer 17

80% asymptomatic, 20% vague symptoms

Question 18

Hep C blood test?

Answer 18

Serology: Ab only, viral PCR

Distinguish current from past - RNA

Question 19

Hep C treatment?

Answer 19

CURE: anti-viral drug combo, 8-12 weeks, >90% cure

Question 20

What is PEP?

Answer 20

Post exposure prophylaxis

HIV: up to 72 hours, x3 ARVs

Hep B: booster immunisation or Ig

Hep C: none available

Question 21

When comparing HIV, Hep C, Hep B, what is the risk of transmission?

Answer 21

HIV 1/300,
HC 1/30,
HB 1/3

Question 22

What is HIV seroconversion illness?

Answer 22

Sign that the immune system is reacting to the presence of the virus in the body; the point at which the body produces antibodies to HIV

S+S = fever, malaise, arthralgia, headache, sore throat. lymphadenopathy, rash

Question 23

What is the HIV window period?

Answer 23

Period of time quoted that a test will accurately detect the presence of the disease

4th gen combo assay (EIA) = ~2 weeks, but 4 weeks quoted to be on safer side
- detects anti-HIV Ab, p24 Ag