Tuberculosis (TB) is a major global health concern and a leading cause of death from a single infectious disease, second only to
COVID-19. The disease is caused by the bacterium Mycobacterium tuberculosis, which primarily affects the lungs but can spread to other parts of the body. Despite being preventable and curable, TB remains a significant public health challenge due to multiple factors including drug resistance, co-infections, and social determinants of health.
How is Tuberculosis Transmitted?
TB is an airborne disease, transmitted through droplets released when an infected person coughs, sneezes, or talks. Inhalation of these droplets can lead to either
latent TB infection or active disease. It is important to note that not everyone infected with the bacterium will develop active TB. In fact, most people who breathe in the bacteria and become infected are able to fight it off and prevent the disease from developing, resulting in a latent infection.
What are the Symptoms of TB?
Symptoms of active pulmonary TB, which affects the lungs, include a persistent cough lasting more than three weeks, chest pain, and coughing up blood. Other general symptoms include fatigue, weight loss, fever, and night sweats. Extrapulmonary TB, which affects organs other than the lungs, can cause symptoms specific to the affected area, such as back pain in spinal TB or lymph node swelling in cervical TB.How is TB Diagnosed?
The
Tuberculin Skin Test (TST) and the
Interferon Gamma Release Assays (IGRAs) are common diagnostic tools for detecting TB infection. For active TB, sputum smear microscopy, culture, and molecular tests such as the GeneXpert MTB/RIF assay are used to confirm diagnosis and assess drug resistance. Chest X-rays are also commonly used in conjunction with these tests to evaluate the presence and extent of lung involvement.
What is Drug-Resistant TB?
Multidrug-resistant TB (MDR-TB) occurs when the bacteria become resistant to at least isoniazid and rifampicin, the two most potent TB drugs. Extensively drug-resistant TB (XDR-TB) involves resistance to additional drugs. Drug-resistant TB poses a significant challenge to treatment, requiring longer, more complex, and more expensive regimens that can have severe side effects. The rise of drug-resistant TB highlights the importance of adherence to prescribed treatment regimens and adequate public health strategies.
How is TB Treated?
Treatment for drug-susceptible TB typically involves a 6-month regimen of four first-line anti-TB drugs: isoniazid, rifampicin, ethambutol, and pyrazinamide. Adherence to the full course of treatment is crucial to cure the disease and prevent the development of drug-resistant strains. For MDR-TB and XDR-TB, treatment is more prolonged and may involve second-line drugs that are less effective, more toxic, and costly. Newer drugs like bedaquiline and delamanid have been introduced to improve treatment outcomes for drug-resistant TB.What are the Challenges in TB Control?
One of the main challenges in TB control is the
co-infection with
HIV, as people living with HIV are more susceptible to developing active TB due to their weakened immune systems. Additionally, social determinants such as poverty, malnutrition, and overcrowding contribute to the spread of TB. Furthermore, the stigma associated with the disease can deter people from seeking diagnosis and treatment. Efforts in TB control must address these multifaceted issues through integrated approaches combining medical, social, and policy interventions.
What are the Current Prevention Strategies?
Prevention strategies include vaccination with the Bacillus Calmette-Guérin (
BCG) vaccine, which is primarily given to infants in countries with high TB prevalence. Although the BCG vaccine provides limited protection against pulmonary TB in adults, it is effective in preventing severe forms of TB in children. Public health strategies also focus on early detection and treatment of active cases, contact tracing, and preventing the progression from latent TB infection to active disease through preventive therapy.
What is the Future of TB Research?
Ongoing research is focused on developing more effective vaccines, improving diagnostic tools, and discovering new treatments, especially for drug-resistant TB. The development of shorter and less toxic treatment regimens is a key area of interest. Additionally, research efforts aim to better understand the transmission dynamics and the socio-economic factors contributing to TB prevalence, which could lead to more effective interventions.In conclusion, tuberculosis remains a significant global health challenge. Addressing TB requires a comprehensive approach that includes improved diagnostic methods, effective treatment regimens, and strategies to combat drug resistance and co-infections. Public health measures, along with research and development, are crucial in controlling and eventually eliminating this devastating disease.
