4th National Seminar on Tuberculosis August, 2000, Ulaanbaatar
Epidemiology and Control of Tuberculosis
Toru Mori, M.D.
Research Institute of Tuberculosis,
Japan Anti-Tuberculosis Association
1. Natural history of tuberculosis
1. Infection
Risk of droplet (nucleus) infection;
- Smear positive?
- How long before diagnosis?
- How close is the contact?
- Closed space?
Prevalence of Infection
2. Clinical Development of TB
Development of cellular immunity and disease development
- Primary development: Primary tuberculosis (10-20%)
- Secondary development: Chronic disease (10%, Life-long)
Which factors are important for disease risk?
Balance between Virulence and Resistance (immunity and nature)
- Infection with close contact and from heavily positive patient
- Age: young infancy and adolescence (but, old age?)
- Immunocompromized hosts: HIV/AIDS, Diabetes, Hemodialysis, Silicosis, Corticosteroid therapy,...
- Natural resistance: Nutrition
- Genetic traits: Lean & tall body type, gastric ulcer, specific genes?
- Psychological stress
3. Fate of TB Patients
- Death
- Cure
- Chronics
- Average duration of disease
2. Intervention with Modern Methods
1. Infection control
How to reduce infection?
- source of infection: early detection and treatment, mask
- removal of infectious droplet: ventilation
-inhalation: N95 type respirator (to medical personnel)
2. Prevention of disease
BCG vaccination
Chemoprophylaxis:
3. Treatment of Disease
Case detection and Chemotherapy
Purposes:
- Life and QOL saving
- Prevention of MDR-TB
Who should be treated? - Case definition
Smear negative and X-ray positive?
Benefit/Risk/Cost: Epidemiology, QOL/Suffering, Accuracy in Dx
What are the outcomes of treatment?
- Cure
- Death (TB or non-TB)
- Failure and relapse
- Absconding
Monitoring treatment progress: Cohort system
