Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Global Health BSc 2018/19 - CDMM1 > TB - 1-4 > Flashcards

TB - 1-4 Flashcards

1
Q

What is the incidence of TB worldwide?

A

10 million new cases worldwide in 2017 (WHO)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How many cases of the incidence of global TB have HIV?

A

1.2 million - high incidence in SSA as linked with HIV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which is more prevalent: latent TB or active TB?

A

More people with latent TB than active

1 in 7 people have latent TB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which 6 countries account for 60% of TB cases worldwide?

A

India, Pakistan, Indonesia, China, Nigeria, South Africa

Half of cases are rifampicin resistant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the trend in TB incidence compared to mortality?

A

TB deaths falling faster than TB incidence but people still getting latent TB in LMICs
Decline in incidence rates since 2010 exceeded 4% per year in several high TB burden countries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the definition of elimination in a TB setting?

A

< 1 case per million/year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the definition of pre-elimination in a TB setting?

A

< 10 cases per million/year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is there a high incidence of TB in former Soviet Union countries?

A

Collapse of the healthcare system + therefore poor access to healthcare
Civil unrest, inequality + poverty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the definition of Multi-Drug Resistance TB?

A

Resistant to rifampicin + isoniazid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How many people have MDR-TB?

A

Roughly 460 000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where is MDR-TB significantly prevalent in?

A

Russia, China + India

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What HIC country is TB still prevalent in?

A

UK!
8.9 new cases per 100 000
In 2017, lowest number of new TB cases for past 30 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What % of migrants have MDR-TB in the UK?

A

70%; 30% Native - marginated or economically suffering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the 5 outcomes of an exposed person to TB?

A

1) Uninfected - insufficient infecting dose + mucosal barriers
2) Cleared - Innate response but no B cell response
3) Contained - local immune response but not detectable systematically
4) Latent TB infection - Innate + adaptive immunity
5) Active TB infection - 5% of all people exposed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the natural course of Mtb infection?

A

Disease most likely occurs in the first few years of infection + then declines e.g. S Korea + Taiwan have an increased prevalence in the elderly as they were exposed when they were young + now reactivated when their immune systems are weak

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the predisposing factors to TB?

A 
HIV
Malnutrition
Diabetes
Alcoholism
Deficiency of TNF-a --> encourages pro/anti-inflammatory balance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the innate immune response to TB?

A

TB recognised by PRRs on macrophages in the lung
Macrophage activated and causes a local response
Cytokines released to induce adaptive response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the adaptive response to TB?

A

TB travels to lymph nodes + activates dendritic cells
Dendritic cells activate T cells - T cell priming
T cells go to the lung and activate IFN-gamma which increases macrophage response and all gather to the lung
There a protective granuloma forms - causes symptoms - If any present, this is latent TB
This then turns into transmissive granuloma whereby it bursts if immune system can’t handle it - active TB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When does the first immune response to TB occur?

A

Usually 8 -12 days post infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe why there is a symbiosis between TB and immune response

A

If there is an impaired immune response e.g. from HIV, malnutrition, diabetes, alcoholism - disease
If tissue damage e.g. pro inflammatory > anti-inflammatory - disease, transmission (problem with forming TNF-alpha so no granuloma forms
If balance between pro-inflammatory = anti-inflammatory - equilibrium so no disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 2 diagnostic tests for TB?

A

TST (Tuberculin skin test) + IGRA (Interferon gamma release assay)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does a TST work?

A

If antibodies produced before will produce a positive TST result + cause an inflammatory response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the weaknesses of TST?

A

Can’t differentiate between latent or active TB
False +ve if exposed to other mycobacterium e.g. in the soil (cross-reactivity)
False +ve for BCG as it contains tuberculin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the strengths of IGRA?

A

Strong specificity for antigens in Mtb that are not in BCG - Less likely to get false positives
However, more costly + require work in the lab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the WHO Tb strategy?
END TB 2015-2030
26
What is in the END TB 2015-2030 strategy?
``` WHO Tb strategy Vision: world free of TB Goal: reduce TB epidemic 95% reduction in deaths 90% reduction in incidence 0% to suffer catastrophic costs = >40% of total income ```
27
Who should be tested following the WHO End TB strategy?
Should systematic test for LTBI and treat | Definitely test and treat: HIV, Exposed, Healthcare workers
28
Does the WHO use IGRA/TBT?
Yes, if no IGRA still use TBT | High incidence, high burden
29
What is the PHE strategy for TB?
Collaborative TB Strategy for England 2015-2020
30
What does the Collaborative TB Strategy for England 2015-2020 entail?
Voluntary screening: | Migrants from countries of incidence > 50/100 000 year
31
What is the problem with the Collaborative TB Strategy for England 2015-2020?
``` GP registration? Undocumented migrants Adherence Language Accessibility Loss to follow up - refer to cascade of care ```
32
What does PHE say in terms of screening for TB?
IGRA + TST | Low incidence, high burden
33
What type of vaccine is the BCG?
Live attenuated
34
What is the gold standard vaccine for TB?
BCG
35
When was BCG made?
In 1921, cultured from Mycobacterium. bovis and took 11 years
36
How available is the BCG?
Widely available - different countries have different stocks due to controversial efficacy
37
When should people be vaccinated?
Before 1 year old as more efficacious in infants due to immunological maturation
38
What are the strengths of the BCG?
Safe Widely available Works in kids and provides immunity against TB meningitis Cures bladder cancer and improves outcomes in leprosy Cheap
39
What are the weaknesses of BCG?
Doesn't work in high-incidence countries but works in HICs - tragedy of BCG Too many different strains of vaccine - variable efficacy: 0-80% Fridge storage Doesn't work in lifelong immunity Injectable Don't have anything for LTBI/ATBI Can't be used in immunocompromised patients
40
Why is there a variability in efficacy of the BCG?
Cross-reactivity with previous mycobacterium exposure e.g. in the soil Strain variation - no horizontal transmission so lost genes of Mtb Nutritional Other infections Population genetics
41
What are the 5 new TB candidates?
``` MTBVAC M72/AS01 MVA85A VPM1002 H4:IC31 ```
42
What are the characteristics of MTBVAC?
Live attenuated - first and only Mtb live vaccine Safe TB + HIV -ve
43
What are the characteristics of M72/AS01?
Conjugate/subunit - most promising candidate Safe High efficacy (54%) in adults Can be used in TB or HIV +ve
44
What is the most promising TB Vaccine candidate?
M72/AS01 Broom (2018) - Very good and worth investing in vaccines as vaccines cost less than the burden of TB Needs more funding
45
What are the characteristics of MVA85A?
Used as a BCG booster but failed | Large Phase III RCT w/ 3000 people in S. Africa but failed - lots of money was invested
46
What are the characteristics of VPM1002?
Recombinant protein based on BCG, Used in kids/adolescents Ongoing trials since 2012/2015 TB + HIV - ve
47
What are the characteristics of H4: IC31?
BCG re-vaccination Nemes et al did 3 armed RCT and found BCG was better than H4:IC31 > Placebo Generally still low efficacy
48
What did Kaufmann, 2011 say about vaccination?
Vaccines are expensive so need acknowledge this MDRTB is a huge problem but nothing is being done Need predictors of how trials are doing e.g. MVA85A
49
What is a key driver to the problems of HIV + MDR-TB?
HIV epidemic | Young children have similar presentations for TB as HIV Patients due to an immature immune system
50
What is the incidence of TB in Africa?
High due to also high HIV burden
51
What are the issues with HIV TB coinfection?
Less likely classical presentation, more likely extra pulmonary (more serious), X ray change variable, tests less sensitive, false -ves
52
What is the treatment regime for TB?
``` RIPE Rifampicin Isoniazid Pyrazinamide Ethambutol 6/12 months minimum ```
53
What is an extensively drug resistant TB?
Resistant to isonniazid and rifampicin AND any fluoroquinolone + at least one of three injectable second-line drugs
54
Why is MDRTB more prevalent in the former Soviet Union countries?
Due to collapse of the healthcare system
55
What are the interventions to control MDR/XDRTB?
``` Invest in R&D for new vaccines, drugs + diagnostics Optimise MDR + XDRTB management Prioritise infection control Address global workforce crisis Address lab costs Ensure access to high quality drugs Finance - abolish barriers to care Restrict availability of anti-TB drugs for efficacy The Three I's for TB/HIV (WHO) DOTS (End TB Strategy 2015) Patient activism/education ```
56
What is the challenge to R&D for new vaccines, drugs + diagnostics?
Dx takes time as TB must be grown New molecular targets in diagnostics Costly Not always easy to detect pathogen - children
57
What is the challenge to prioritise infection control?
In high prevalence settings, many hospitals have high rates of undiagnosed TB Natural ventilation proven benefit + UV light
58
What is the challenge to addressing the global workforce crisis?
Migration of healthcare workers - spread globally (Williams 2015)
59
What are the 3 I's for TB/HIV (WHO)?
Intensified case finding Isoniazid Preventative therapy (IPT) - Treating those with LTBI with isoniazid for 9 months Infection control for TB
60
What is causing the TB burden in the migrant population?
Reactivation of remotely-acquired latent TB infection following migration from high TB burden, LICs + migrated to HICs, low TB burden countries
61
Historically, what have HICs focused on combating TB control?
Focused on combating active TB but with an increasing migrant population where TB burden lies in LTBI, new mechanisms to tackle this burden are needed
62
What does evidence suggest HICs do to control TB?
LTBI screening post-arrival and Rx to certain migrant groups | Barriers to access + implementation + sub-optimal Rx must still be overcome to achieve elimination
63
What is the most effective mechanism to screen?
Pre-arrival screening for active TB Targeted post arrival screening for LTBI in migrants from intermediate/high burden settings Single step IGRA
64
What are the challenges to post-arrival screening for LTBI?
Limited uptake - loss in the cascade of care Acceptance Completion of therapy
65
How do foreign-born individuals bear the TB burden in HICs?
Disproportionate | Reactivation of LTBI is important in migrants

Global Health BSc 2018/19 - CDMM1 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions