TUBERCULOSIS: IMPORTANT MEASURES FOR ITS PREVENTION
Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis (MTB) bacteria. Tuberculosis generally affects the lungs, but can also affect other parts of the body. Most infections show no symptoms, in which case it is known as latent tuberculosis. About 10% of latent infections progress to active disease which, if left untreated, kills about half of those affected. Typical symptoms of active TB are a chronic cough with blood-containing mucus, fever, night sweats, and weight loss. It was historically called consumption due to the weight loss. Infection of other organs can cause a wide range of symptoms.
Tuberculosis is spread from one person to the next through the air when people who have active TB in their lungs cough, spit, speak, or sneeze. People with latent TB do not spread the disease. Active infection occurs more often in people with HIV/AIDS and in those who smoke. Diagnosis of active TB is based on chest X-rays, as well as microscopic examination and culture of body fluids. Diagnosis of latent TB relies on the tuberculin skin test (TST) or blood tests.
Prevention of TB involves screening those at high risk, early detection and treatment of cases, and vaccination with the bacillus Calmette-Guérin (BCG) vaccine. Those at high risk include household, workplace, and social contacts of people with active TB. Treatment requires the use of multiple antibiotics over a long period of time. Antibiotic resistance is a growing problem with increasing rates of multiple drug-resistant tuberculosis (MDR-TB) therefore preventing this disease is the most appropriate way.
PREVENTION FOR TUBERCULOSIS
Tuberculosis prevention and control efforts rely primarily on the vaccination of infants and the detection and appropriate treatment of active cases. The World Health Organization (WHO) has achieved some success with improved treatment regimens, and a small decrease in case numbers.
The only available vaccine as of 2011 is Bacillus Calmette-Guérin (BCG). In children it decreases the risk of getting the infection by 20% and the risk of infection turning into active disease by nearly 60%. It is the most widely used vaccine worldwide, with more than 90% of all children being vaccinated. The immunity it induces decreases after about ten years. As tuberculosis is uncommon in most of Canada, Western Europe, and the United States, BCG is administered to only those people at high risk. Part of the reasoning against the use of the vaccine is that it makes the tuberculin skin test falsely positive, reducing the test’s usefulness as a screening tool. Several vaccines are being developed.
PUBLIC HEALTH INTERVENTION
Public health campaigns which have focused on overcrowding, public spitting and regular sanitation (including hand washing) houses being adequately ventilated, educating people on cough etiquette and respiratory hygiene and that they should follow such practice at all times, has helped to either interrupt or slow spread which when combined with contact tracing, isolation and treatment helped to dramatically curb the transmission of both tuberculosis and other airborne diseases which has led to the elimination of tuberculosis as a major public health issue in most developed economies. Other risk factors which worsened TB spread such as malnutrition were also ameliorated, but since the emergence of HIV a new population of immuno-compromised individuals was available for TB to infect.
The benefits and risks of giving anti-tubercular drugs in those exposed to MDR-TB is unclear. Making HAART therapy available to HIV-positive individuals significantly reduces the risk of progression to an active TB infection by up to 90% and can mitigate the spread through this population.