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Western Cape Burden of Disease. HIV and Tuberculosis. Beverly Draper David Pienaar Thomas Rehle Warren Parker. Overview. The current HIV & TB situation in the Western Cape What explains the current situation? - Risks - Interactions between HIV & TB

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western cape burden of disease

Western Cape Burden of Disease

HIV and Tuberculosis

Beverly Draper

David Pienaar

Thomas Rehle

Warren Parker

  • The current HIV & TB situation in the Western Cape
  • What explains the current situation?

- Risks

- Interactions between HIV & TB

  • The predicted future situation
  • Proven interventions
  • Potential multi-sectoral strategies

Estimated HIV cases1 for selected areas2 of the Western Cape - 2007

1. Dorrington R, Centre for Actuarial Research

2. The 6 areas selected represent ~90% of estimated total of ~283 000

Worcester/De Doorns ~6 500

Wellington/Paarl ~8 800

Cape Town

~209 000

Stellenbosch ~5 100

Theewaterskloof/Grabouw ~5 400

Mossel Bay/George/Knysna and Bitou ~17 000

tb distribution pgwc etr 2005 data
TB distribution (PGWC ETR 2005 data)

Categorisation of TB clinics


Distribution of high burden TB clinics (TB ‘hotspots’) in the Western Cape – 2005

(DOH ETR 2005 data)

All 22 ‘high burden’ clinics are located in the indicated areas


18/22 of the highest burden clinics are in the metro

  • 12/18 are in a 10km x 15km area that straddles 5 sub-districts

(ETR 2005 data)

Approximately 25% of the registered TB cases in the province

current service difficulties
Current service difficulties
  • Significant stigma: HIV and TB
  • Most HIV cases and an unknown amount of TB cases are undiagnosed
  • Delayed health seeking behaviour: late entry into care, HIV and/or TB, with advanced disease.
  • TB diagnostic challenges

-HIV reduces the accuracy of the standard TB test

  • Human resources challenges
  • TB adherence difficulties
  • ART adherence difficulties
  • High proportion of re-treatment TB cases
  • Emerging TB resistance

- mono-drug, MDR and XDR

why do certain areas carry the burden of disease
Why do certain areas carry the burden of disease?
  • There are proven risk factors associated with high prevalence HIV areas:

The ‘deprivation cluster’ of:

  • Migration
  • Overcrowding
  • Poverty
  • Malnutrition

Produces (and reproduces) social vulnerability


How does social vulnerability impact on individual HIV risk?

  • By exacerbating the following known risk factors:
  • Not knowing one’s HIV status
  • Stigma and discrimination
  • Age mixing
  • Early sexual debut
  • Transactional sex
  • Partner turnover/concurrency
  • Alcohol misuse


-poor decision-making skills

-economic necessity

how do biological factors impact on individual hiv risk
How do biological factors impact on individual HIV risk?
  • By making some people more likely to transmit HIV and others more vulnerable to HIV
  • Sex & age
  • Viral load
  • Sexually transmitted infections
  • Mother to child transmission
what are the risks factors for being exposed to tb
What are the risks factors for being exposed to TB?
  • The ‘deprivation cluster’ of: impoverishment, poor nutrition, migration, overcrowded dwellings, existing high TB prevalence and incidence, poor education, ignorance of TB transmission mechanisms and of TB symptoms

“85-90% of those people with normal immunity

who inhale TB do not develop disease”


What are the risks factors for inhaled TB progressing to tuberculosis disease?

  • “by far the most powerful risk identified is concurrent HIV infection”
how hiv impacts on tb in the western cape
How HIV impacts on TB in the Western Cape
  • More TB in the HIV+ population at all stages of HIV disease, but especially with advanced HIV disease
  • TB program placed under increased pressure:

- number of cases

- clinical time required to make a diagnosis

  • Greater potential for poor clinical outcomes
  • Greater potential for drug resistance
  • Greater risk of exposure to TB for the general population
  • More deaths due to TB/HIV
hiv and tb in clinical practice
HIV and TB in clinical practice

60-70% of ART patients either had concurrent TB or have had a previous episode of TB




60-70% of TB patients in Khayalitsha are HIV+

how do we predict future caseload
How do we predict future caseload?
  • HIV
  • A person can only get it once and then they’ve got it for life.
  • A “relatively simple” modeling exercise, but it is being complicated by the impact of interventions
  • TB
  • A person can get it, be cured, and get it again. The risk of this happening increases as HIV disease becomes more severe. Also affected by background HIV prevalence which changes over time
  • Mathematically complex

= approx. 30 new cases/day

Future burden - HIV

Estimated HIV scenario1 for selected areas of the Western Cape to 2015

1. Dorrington R, Centre for Actuarial Research

future burden tb
Future burden -TB

(Lawn S. et al, CID, 2006;42:1040-7)

in summary what does the future hold
In summary, what does the future hold?
  • We know where the high prevalence HIV areas are
  • We have a good idea of how many HIV cases to expect
  • We know TB is going to occur where HIV is prevalent
  • We cannot predict TB caseload as accurately
  • Evidence suggests TB is going to continue to increase even after HIV prevalence stabilises
  • This TB is likely to be more difficult to diagnose
  • Adherence, and consequently, resistance is likely to play an increasing role
  • Further down the line, HIV resistance is likely to become a problem
proven interventions that reduce hiv transmission
Proven interventions that reduce HIV transmission
  • PMTCT. An excellent intervention
  • Condoms. They work. But we can’t get people to use them consistently (or, at all)
  • STI treatment. Reduces risk of HIV transmission
  • Circumcision. Reduces risk of acquisition in the male only. There are concerns about logistics and perceived invulnerability
proven interventions that impact on behaviour
Proven interventions that impact on behaviour
  • Mass media campaigns. Increase the number of people who present for HIV testing
  • VCT. People who test HIV+ are more likely to engage in safer sex. Not a uniform finding though, social context influences this.
proven interventions that impact on tb risk
Proven interventions that impact on TB risk
  • Isoniazid preventative therapy. Lowers risk of active TB in those with a positive TST. But, need to prove that TB is not present otherwise might contribute to drug resistance. Very difficult thing to prove.
  • Anti-retroviral therapy. Lowers the risk incompletely. Still 5-10 times more chance of getting TB than an HIV uninfected person
  • Radio campaigns. Improved health seeking behaviour of those with TB symptoms
how do we approach this
How do we approach this?
  • There are a limited number of interventions that have hard proof of efficacy. Might have to rely on logic and plausibility
  • There are clear health sector demands, these need to be addressed
  • There are areas beyond the health sector where the potential exists for multi-sectoral interventions
health sector strategies
Health sector strategies
  • Strengthen PMTCT
  • Increase VCT and ‘opt-out’ testing
  • Strengthen TB program capacity considerably

- Active case finding

- Diagnostic skill: doctors and CNPs

- Diagnostic equipment- X-rays

- Laboratory services – diagnosis, and resistancetesting

- Monitoring and recording capacity

- ?Investigate alternative adherence models

  • Strengthen ART roll-out
  • Establish best models for TB/HIV integration
what should we be doing about the deprivation cluster
What should we be doing about the “deprivation cluster”?

We need to address the root causes

  • Migration – ‘push’ and ‘pull’ factors
  • Overcrowding – housing quality
  • Poverty – socio-economic conditions
  • Malnutrition – grants, food vouchers

The problem is, apart from the fourth, these are ‘structural’, and in some cases, national issues, with medium to long term timelines.

Although these issues must certainly be addressed, they will not rapidly improve infectious disease outcomes

what should we be doing about the social individual factors
What should we be doing about the social/individual factors?

We need to impact on social attitudes and individual behaviour.

We desperately need to stop HIV transmission

  • Heighten awareness of individual risk in high-prevalence areas
  • Reduce stigma and discrimination
  • Normalise HIV testing in relationships
  • Reduce risky sexual behaviour

-consistent condom use

-delay sexual debut

-encourage monogamous relationships

-discourage age mixing

-avoid alcohol and drug misuse

  • Optimise health seeking behaviour
  • Very importantly, support and encourage adherence behaviour
potential strategies
Potential strategies
  • Introduce epidemiologically-led behavioural interventions
  • Target hotspots first
  • Identify and manage at-risk groups earlier
  • Integrate prevention and treatment
  • Adapt the relevant services within the social cluster platform of public services
  • What is it going to take to impact on behaviour?
  • How to ‘normalise’ HIV testing?
  • How to cope logistically with more people testing?
  • How to get other sectors involved?
  • Best ways to impart health information?
  • What information to impart?
  • Can health services cope?