What Are the Symptoms of Tuberculosis and Is It Contagious?
Understanding the Common Signs of Tuberculosis
Tuberculosis (TB) primarily affects the lungs and manifests through a range of respiratory symptoms. The most common signs include persistent coughing, often accompanied by sputum production that can last for weeks. In more advanced cases, patients may experience hemoptysis—coughing up blood—which varies in severity depending on the extent of lung damage and the size of the affected blood vessels. While not every individual with TB will have bloody sputum, its presence should prompt immediate medical evaluation.
Systemic Symptoms Indicating Active Infection
Beyond localized lung issues, tuberculosis triggers widespread systemic effects due to the body's immune response and chronic infection. Many patients report low-grade fever, especially in the afternoon or evening, along with night sweats that can drench bedding. Fatigue, unexplained weight loss, and a general sense of malaise are also hallmark features of active TB. Women may notice menstrual irregularities, which can sometimes be an overlooked clue in early diagnosis. These symptoms often develop gradually, mimicking other chronic illnesses, making awareness crucial for timely detection.
Is Tuberculosis Contagious? Understanding Transmission Risks
TB is classified as a Category B infectious disease under national health regulations, highlighting its public health significance. However, it's important to note that not all individuals diagnosed with pulmonary tuberculosis are contagious. The key factor determining transmissibility is whether the patient is "sputum-positive"—meaning Mycobacterium tuberculosis can be detected in their respiratory secretions through laboratory testing.
How TB Spreads: The Role of Airborne Droplets
Only those with active, sputum-positive TB are capable of spreading the bacteria. When infected individuals cough, sneeze, or speak, they release tiny droplets containing the TB bacillus into the air. These microscopic particles can remain suspended as aerosols, particularly in poorly ventilated indoor spaces. Healthy individuals with weakened immune systems are at higher risk of inhaling these pathogens and developing latent or active TB infections.
When to Seek Medical Evaluation
Given that TB progresses slowly and symptoms may resemble those of bronchitis or pneumonia, misdiagnosis is not uncommon. If someone experiences a prolonged cough lasting more than two to three weeks, especially with weight loss and night sweats, healthcare providers recommend screening for tuberculosis. Standard diagnostic tools include chest X-rays, sputum tests, and molecular assays like GeneXpert to detect TB DNA rapidly.
Prevention and Public Health Measures
Early identification and treatment of infectious cases are essential in controlling TB spread. Sputum-negative patients typically pose minimal risk and can be managed safely at home, while sputum-positive individuals may require temporary isolation until they become non-infectious after starting effective antibiotic therapy. Vaccination with BCG, improved ventilation, and wearing masks in high-risk settings further reduce transmission rates, especially in endemic regions.