What is the difference between latent TB and active TB?

Latent TB means you carry the bacteria but your immune system keeps it in check—you have no symptoms and are not contagious. Active TB means the bacteria are multiplying, causing symptoms, and you can spread the disease.

Is TB still a problem today?

Yes, TB remains one of the world's deadliest infectious diseases, killing about 1.3 million people annually. Drug-resistant TB is a growing concern that complicates treatment efforts.

Why does TB treatment take so long?

TB bacteria reproduce slowly and can become dormant, requiring prolonged treatment to eliminate all bacteria. Stopping antibiotics early increases the risk of relapse and drug resistance.

InfectiousICD-10: A15About 10 million people develop active TB worldwide each year; approximately 8,000 cases in the US annually

Tuberculosis

Also known as: TB, Mycobacterium tuberculosis infection

Tuberculosis is a potentially serious infectious disease primarily affecting the lungs, caused by the bacterium Mycobacterium tuberculosis. TB spreads through airborne droplets when an infected person coughs, sneezes, or speaks. While latent TB infection causes no symptoms and is not contagious, active TB disease can be fatal without proper treatment, which typically involves a months-long course of antibiotics.

Symptoms

Persistent cough lasting three weeks or more

Coughing up blood or sputum

Chest pain or pain with breathing

Unintentional weight loss

Fatigue and weakness

Fever and night sweats

Chills

Loss of appetite

Causes

Infection with Mycobacterium tuberculosis bacteria
Airborne transmission through respiratory droplets
Reactivation of latent TB infection when the immune system weakens

Risk Factors

Close contact with someone who has active TB
Weakened immune system from HIV, diabetes, or immunosuppressive medications
Living in or traveling to areas with high TB prevalence
Healthcare workers exposed to TB patients
Living in crowded or poorly ventilated conditions
Substance abuse or homelessness

Diagnosis

Tuberculin skin test (Mantoux test)
Interferon-gamma release assay blood test
Chest X-ray for signs of active disease
Sputum smear microscopy and culture
GeneXpert rapid molecular test for TB and drug resistance

Treatment

Standard four-drug regimen (isoniazid, rifampin, ethambutol, pyrazinamide) for 6-9 months
Direct observed therapy to ensure adherence
Shorter regimens for latent TB infection
Second-line drugs for drug-resistant TB
Nutritional support and rest during treatment

Prevention

BCG vaccine in high-prevalence countries
Contact tracing and treatment of latent TB infection
Infection control measures in healthcare facilities
Improving ventilation in congregate settings

When to See a Doctor

Cough lasting more than three weeks, especially with blood
Unexplained weight loss with night sweats
Known exposure to someone with active TB
Positive TB skin or blood test

Frequently Asked Questions

Related Conditions

Pneumonia

Respiratory

HIV/AIDS

Infectious

Sarcoidosis

Autoimmune

Lung Cancer

Cancer

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