Global Tuberculosis and Tuberculosis in Africa

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Global Tuberculosis and Tuberculosis in Africa

• Kayla Laserson
• Richard Laing
• TLC Course
• April, 2001

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Tuberculosis A Global Emergency

• One third of the worlds population is infected
• TB kills 5,000 people a day 2 to 3 million/yr
• More than 100,000 children will die this year
• Hundreds of thousands of children will become TB
  orphans this year
• HIV and TB co-infection are producing explosive
  epidemics
• MDR is seriously threatening global TB control

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TB is the Leading Infectious Cause of Death among
Persons gt5 years old
Number of deaths (millions)
Source WHO World Report 2000
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Tuberculosis the Disease (1)

• Caused by mycobacterium, slow growing slow
  healing
• Infection is initially latent, only skin test
  positive with no symptoms
• A proportion of infected individuals progress to
  active disease usually affecting lungs
  (infectious) but any organ can be a site of
  disease (non-infectious)

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Tuberculosis the Disease (2)

• Normal progression of disease
• 50 die, 25 spontaneous cure, and 25 chronic
  excretors
• Treatment requires multiple drugs for prolonged
  periods. Good results possible
• Treatment interruptions or monotherapy lead to
  drug resistance
• Drug resistance can be transmitted (primary) or
  developed (secondary)

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Tuberculosis the Disease (3)

• TB is primarily a disease of poverty aggravated
  by overcrowding, poor ventilation and
  undernutrition
• Prior to drug treatment, incidence fell with
  improvements in environment and living standards
  in developed countries
• Recently TB has dramatically increased due to HIV
  and collapse of economic and health systems

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Treatment of TB

• TB is treated with multiple drugs to avoid drug
  resistance and treatment failures
• Intensive phase 4 drugs Rifampicin, Isoniazid,
  Pyrazinamide, and Ethambutol or Streptomycin
• Continution phase 2 drugs INH Rif or Eth
• If drugs are counterfeit or substandard, may
  cause treatment failures and lead to the
  development of Multidrug-Resistant TB (MDRTB)

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Risk Factors for TB

• Poverty and unemployment
• Homelessness
• Congregate settings (prisons)
• Alcoholism and drug abuse
• HIV

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World TB Situation Estimated incidence of TB 1999

• Country Cases (000S) Rate /100K
• 1 India 1,847 185
• 2 China 1,300 103
• 3 Indonesia 590 282
• 4 Nigeria 327 301
• 9 South Africa 197 495
• 13 Kenya 123 417
• 19 Uganda 72 343
• 21 Zimbabwe 65 562
• Angola 16
  129
• Botswana 8 513
• Ghana 10 53
• Lesotho 4 sm
• Swaziland
  2 sm

Source Global Tuberculosis Control WHO Report
2001
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Geographical Distribution of Notified Cases of
TB, 1999
Africa
Western Pacific
17
22
Americas
6
4
Middle East
10
41
Southeast Asia
Europe
Source Global Tuberculosis Control WHO Report
2001
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Source Global Tuberculosis Control WHO Report
2000
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Treatment Outcomes for Smear Cases 1998 Cohort
DOTS/ Non-DOTS Strategy
Country Cured CpltRX Died Failed Default Tfrd
Success 1 India 83 1.2 4.4 2.7
7.5 1.0 84 1.9 22 0.1
0.1 2 0.2 24 2 China 97 0
1.2 0.8 0.6 0.3 97
85 0 1.8 6.5 4.5
1.7 85 9 S. Africa 68 6.6 5.6 1.7
6.8 12 74 30 17 5.1 0.9
13 34 47 11 DRC 58 12 5.3
1 9.4 8.4 70 21 Zimbabwe 50
19 10 0.3 8.3 12
70
Source Global Tuberculosis Control WHO Report
2001
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TB and HIV

• Profound impact on TB epidemic in sub-Saharan
  Africa and parts of South East Asia
• Nearly 11 million people co-infected with TB- HIV
• About 8 of TB cases were associated with HIV
  infection in 1997
• Increased TB case fatality rates (23 on average)
  
• TB/HIV cases can be effectively treated with
  existing drugs

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TB Incidence and HIV Seroprevalence in AFRO
Source WHO/CDS
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Effect of HIV on TB in Botswana
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Multidrug-Resistant TB

• Primary resistance is when a person is infected
  with a resistant organism
• Secondary resistance is when a person is treated
  inadequately either because of drug shortages,
  system breakdown, compliance failure OR possibly
  poor DRUG QUALITY
• Cost of treatment very high --gt 2 years of 4-5
  other drugs, with high cost SE

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Prevalence Estimates Vary

• 2000 Resistance Report (72 sites)
• Median, any resistance 11.1 (0-52)
• Median, MDR-TB 1.7 (0-22.1)
• gt3 prevalence MDR Estonia, Henan Zhejiang
  provinces, Latvia, Ivanovo Tomsk oblasts, Iran,
  Mozambique, Tamil Nadu, Peru

WHO. Anti-tuberculosis Drug Resistance in the
World. Report 2 Prevalence and Trends The
WHO/IUATLD Global Project on Anti-Tuberculosis
Drug Resistance Surveillance, 2000
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Distribution of MDR TB in the World
FORMER USSR high MDR
INDUSTRIALIZED WORLD low MDR
MIDDLE EAST MDR?
ASIA high MDR
AFRICA low MDR?
LATIN AMERICA medium MDR
WHO Global TB Programme
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MDR Prevalence in Selected African Countries,
1996-1999 WHO/ IUATLD Survey
Percent
Country
Source WHO. Anti-tuberculosis Drug Resistance in
the World. Report 2 Prevalence and Trends The
WHO/IUATLD Global Project on Anti-Tuberculosis
Drug Resistance Surveillance, 2000
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Policy Response to MDR-TB - DOTS

• Government commitment
• Bacteriologically confirmed diagnosis
• Standardized, short-course, directly observed
  multidrug regimen for treatment of TB (SSCC)
• Regular, uninterrupted supply of quality drugs
  and diagnostic materials
• Systematic monitoring and evaluation of program
  activities

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Newer Policy Response to MDR-TB - DOTS-Plus

• Government commitment
• Bacteriologically confirmed diagnosis (generally
  includes culture and drug susceptibility testing)
• Observed standardized and/or individualized
  multidrug regimens
• Regular, uninterrupted supply of quality
  second-line drugs and diagnostic materials
• Systematic monitoring and evaluation of program
  activities

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Future of TB in World Finely Balanced

• If all existing sensitive cases are treated
  effectively with DOTS effective drugs, rates
  will decline
• But if this does not occur, cases will increase,
  MDRTB will spread, and TB may return to be a
  major global threat
• Ensuring drug quality is an essential component
  of any National TB Program but is often neglected