TB, HIV + AIDS

Question 1

TB is caused by..

Answer 1

mycobacterium tuberculosis, most often affects the lungs

Question 2

What is the lifetime risk of falling ill with TB?

Answer 2

• 5-10% lifetime risk of falling ill with TB
• Those with comprised immune systems (HIV, malnutrition, diabetes): higher risk of falling ill

Question 3

how many people died of tuberculosis in 2019? How many people fell ill worldwide?

Answer 3

• 1.4 mil people died 2019
• 10 mil people fell ill worldwide

Question 4

Who is at risk?

Answer 4

• Adults in their most productive years, however all age groups at risk
• Over 95% cases + deaths in developing countries
• HIV infected people
• Suffering from other conditions impairing the immune system
• Undernutrition
• Alcohol use disorder
• Tobacco smoking

Question 5

Symptoms of TB?

Answer 5

Symptoms
- Cough with sputum and blood at times
- Chest pain
- Weakness
- Weight loss
- Fever
- Night sweats

Question 6

Diagnosis of TB?

Answer 6

• use of rapid molecular diagnostic tests (Xpert MTB/RIF, Xpert Ultra and Truenat assays)
• Diagnosing multidrug-resistant (MDR-TB) and other resistant forms of TB as well as HIV-associated TB can be complex and expensive
• Diagnosis in children particularly difficult

Question 7

Treatment of TB?

Answer 7

• (active, drug-susceptible TB) is treated with a 6-month course of 4 antimicrobial drugs that are provided with information and support to the patient by a health worker or trained volunteer

Question 8

What are preventative measures for TB?

Answer 8

• prevent development of drug resistance through high quality treatment of drug susceptible TB
• Expand rapid testing and detection of drug-resistant TB cases
• Prevent transmission through infection control
• Provide immediate access to effective treatment and proper care
• Increase political commitment with financing

Question 9

What are four scenario’s that may happen after infection?

Answer 9

1) Bacteria don’t get far enough: bacteria are not breathed in
2) Bacteria are breathed in, get in alveoli: get picked up by macrophages. They are destroyed. -> latent
3) Bacteria get breathed in, macrophages cannot destroy the bacteria. -> latent
4) Bacteria get breathed in, bacteria are multiplying and filling up the alveoli. Macrophages are alerted. ‘Active scenario’, the bacteria are thriving.

Question 10

What does HIV do?

Answer 10

• Targets the immune system, weakens people’s defence against many infections, some types of cancer that people with healthy immune systems can fight off
• Virus destroys and impairs function of immune cells

Question 11

What is AIDS?

Answer 11

AIDS = most advanced stage of HIV infection
- Can take many years to develop if not treated
- Defined by the development of certain cancers, infections or other severe long-term clinical manifestations.

Question 12

How many people died from HIV-related causes, how many were newly infected in 2020?

Answer 12

700.000 people died, 1.5 mil newly infected

Question 13

HIV can/cannot be transmitted via kissing or sharing water

Answer 13

cannot

Question 14

What are the symptoms of HIV?

Answer 14

First few weeks: no symptoms/influenza-like sickness (fever, headache, rash or sore throat)
As the immune system is weakened: swollen lymph nodes, weight loss, fever, diarrhoea and cough
Without treatment: severe illness, such as TB, severe bacterial infections, cancers

Question 15

How is HIV diagnosed?

Answer 15

• rapid diagnostic tests that provide same-day results (self-tests)
• no single test can provide a full HIV diagnosis; confirmatory testing is required, conducted by a qualified and trained health or community worker at a community centre/clinic.

Question 16

What do most HIV tests detect? When are they visible?

Answer 16

Most tests detect antibodies (within 28 days these are developed. This is the ‘window’ period:
= When HIV antibodies haven’t been produced in high enough levels to be detected by standard tests and when they may have had no signs of HIV infection, but also when they may transmit HIV to others

Question 17

What is the treatment of HIV?

Answer 17

= combination of three or more antiretroviral (ARV) drugs
- does not cure, but highly suppresses viral replication
- Strengthens the immune system
- WHO recommends lifelong Antiretroviral therapy (ART)

Question 18

• explain the importance of CD4-molecules in HIV infection (no need to memorize names of co-receptors)

Answer 18

= CD4 molecule is present in T-helper cells, dendritic cells and macrophages which are all involved in the immune system. CD4 cells + coreceptors are targeted by HIV in order for the virus to enter the cell. CD4 molecules help immune cells communicate.

Question 19

• explain the importance of CD4-molecules in HIV infection (no need to memorize names of co-receptors)

Answer 19

= CD4 molecule is present in T-helper cells, dendritic cells and macrophages which are all involved in the immune system. CD4 cells + coreceptors are targeted by HIV in order for the virus to enter the cell. CD4 molecules help immune cells communicate.

Question 19

• explain the importance of CD4-molecules in HIV infection (no need to memorize names of co-receptors)

Answer 19

= CD4 molecule is present in T-helper cells, dendritic cells and macrophages which are all involved in the immune system. CD4 cells + coreceptors are targeted by HIV in order for the virus to enter the cell. CD4 molecules help immune cells communicate.

Question 20

• explain what a retrovirus is

Answer 20

= It uses reverse transcriptase to transcribe a complimentary piece of pro-viral DNA. This piece of DNA is inserted into the host DNA, transcribed into new viruses.

Question 21

• explain how the virus multiplies and spreads throughout the body

Answer 21

=pro-viral DNA is inserted into the host DNA: transcribed, virus can multiply. Infects macrophages, dendritic cells, T-cells, which go to the lymph nodes ->can infect many other cells -> big spike in HIV in blood.

Question 22

• describe the time course of HIV virus and T-cell counts in blood (acute and chronic phase)

Answer 22

= Acute reaction (12 weeks): HIV virus first multiplies a lot. There is then a counterattack from the body, controls the replication.
- Then there is a chronic phase (2-10 years): number of viruses slowly increases, T-cells slowly decrease

All together, HIV virus particles and the T-cells mirror each other.

Question 23

• recognize common symptoms of HIV infection and AIDS (“AIDS-defining” conditions)

Answer 23

HIV: 200-500 T cells/mm3
(swollen lymph nodes, oral infections)
AIDS: <200 T cells/mm3
(persistent fever, fatigue, weight loss, diarrhoea)
AIDS-defining conditions: recurrent bacterial pneumonia, pneumocystis pneumonia, fungal infections, tumours, primary lymphoma

Question 24

- describe the most important modes of transmission

Answer 24

Male -> male Male -> female (resource-limited settings) Female -> male (less likely) Drug abuse, mother-to-child transmission

Question 25

- describe what antiretroviral therapy does

Answer 25

= Help live longer + healthier lives, reduce risk of transmission. Combination of medicine which slows down HIV replication.