This paper provides a comprehensive overview of tuberculosis (TB), a widespread infectious disease caused by Mycobacterium tuberculosis. It examines how TB spreads through airborne droplets, the distinction between latent and active infection, and the range of pulmonary and extra-pulmonary symptoms. The paper also discusses the epidemiologic triangle as a framework for understanding TB transmission, identifies key risk factors including HIV and poverty, and reviews global epidemiological data. Additionally, it addresses the roles of community health nurses in TB prevention and management, and outlines the World Health Organization's major initiatives to control the disease worldwide, including responses to multi-drug-resistant tuberculosis.
The paper effectively uses a structured framework — the epidemiologic triangle (agent, host, environment) — to organize its analysis of TB transmission and prevention. This technique is common in public health writing and shows how applying a conceptual model can clarify complex disease dynamics for a general audience.
The paper opens with a definition and description of TB, then moves through symptoms (pulmonary and extra-pulmonary), causative organisms, and risk factors. It follows with global epidemiological statistics, then diagnostic and treatment considerations. The final sections apply the epidemiologic triangle, discuss social determinants of health, and describe the roles of community health nurses and the WHO. This progression from biology to policy mirrors the standard structure of a public health overview paper.
Tuberculosis is a widespread, lethal, and infectious disease caused by Mycobacterium tuberculosis. This bacterial infection usually begins in the form of innumerable strains of mycobacteria. In the past, tuberculosis was also termed phthisis or phthisis pulmonalis. It is widely known by the abbreviations TB or MTB. Tuberculosis is stereotypically a lung infection; however, it can also affect other parts of the body. It can spread through the bloodstream and the lymph nodes to virtually any organ. TB spreads through the air when individuals with an active infection sneeze, cough, or otherwise expel respiratory fluid, transmitting the bacteria to non-infected persons (Al Jahdali, Menzies, & Al Otaibi, 2011).
When individuals with active pulmonary TB sing, sneeze, spit, or cough, they emit infectious aerosol droplets approximately 0.5 to 5 µm in diameter. A single droplet can be sufficient to transmit the disease, since the infectious dose is extremely low — inhalation of as few as five bacteria may lead to infection. Most TB infections are latent and asymptomatic; however, approximately three in ten latent cases may eventually advance to active disease, which, if left untreated, may kill 55% or more of those infected.
The majority of those infected by tuberculosis never develop symptoms, because the bacteria may live in an inactive form within the body for an extended period. Nevertheless, if the immune system weakens — as in elderly adults or people living with HIV — the tuberculosis bacteria may rapidly become active. In their active stage, tuberculosis bacteria cause destruction and death of infected organ tissues. If left untreated, tuberculosis can be fatal. The typical symptoms of active tuberculosis include fever, chronic cough with blood-stained sputum, weight loss, and night sweats.
Al Jahdali, Menzies, and Al Otaibi (2011) note that tuberculosis may infect any part of the body, though it most commonly affects the lungs — a condition referred to as pulmonary tuberculosis. When TB bacteria develop outside the lungs, they cause extra-pulmonary tuberculosis, which may also coexist concurrently with pulmonary TB. The overall signs and symptoms of tuberculosis include chills, fever, loss of appetite, night sweats, fatigue, and weight loss. In many cases, finger clubbing may also occur.
In pulmonary tuberculosis, symptoms may include prolonged cough and chest pain. Occasionally, infected individuals may cough up blood-stained sputum. In rare cases, TB infection may erode the pulmonary artery, causing massive bleeding — a condition termed Rasmussen's aneurysm. TB may develop into a chronic illness and produce extensive scarring within the upper lobes of the lungs (Gerald, Wang, & Elwood, 2008).
Extra-pulmonary tuberculosis spreads beyond the lungs, leading to other forms of TB. The most commonly affected sites include the pleura, the lymphatic system, the central nervous system, the bones and joints, and the genitourinary system. In rare cases, the rupture of a tubercular abscess through the skin may result in tuberculous ulcers.
The primary cause of tuberculosis is Mycobacterium tuberculosis, a small, non-motile bacillus capable of undergoing cell division every 15 to 20 hours. Gerald, Wang, and Elwood (2008) note that MTB can survive in a dry environment for weeks and can withstand weak disinfectants for some time. By nature, the bacteria grow only within the living cells of a host organism before spreading to another host. The M. tuberculosis complex (MTBC) encompasses four other mycobacteria that also cause TB: M. canetti, M. africanum, M. bovis, and M. microti. Other recognized pathogenic mycobacteria include M. avium, M. leprae, and M. kansasii (Al Jahdali, Menzies, & Al Otaibi, 2011).
In addition to bacterial infection, several risk factors increase susceptibility to tuberculosis. One of the most significant is HIV infection, which is a particularly serious problem in sub-Saharan Africa, where rates of HIV positivity are extremely high. Other known risk factors include drug abuse (such as cigarette smoking and alcohol use), overcrowding, malnutrition, and infection with diabetes mellitus.
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