People with TB disease are more likely to spread it to people they spend time with every day. This includes family, friends, and co-workers. When the TB bacteria can live in the body without making you sick, it is called a latent TB infection.
Previous studies have indicated that a higher prevalence of LTBI could occur mainly due to a higher incidence and mortality of TB. According to the WHO, it is estimated that approximately one quarter of the world’s population is infected with Mycobacterium tuberculosis.
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On average, 5-10% of infected people will develop active TB disease in their lifetime. In India, the prevalence rate of latent tuberculosis is very high, at around 40% of the population. Now is the time to know about latent TB infection.
What is true about latent tuberculosis infection?
- Latent TB occurs after a person is infected with the TB bacteria but does not show TB symptoms. TB bacteria can lie dormant in the body for a long time, even decades. In active TB cases, the bacteria reproduce and spread in the body, causing tissue damage.
- People with LTBI do not feel sick and do not spread the disease.
- Although infected people do not manifest the disease, they are at high risk of developing an active infection and are therefore considered a reservoir of TB bacteria.
- Many people with high immunity can normally resist bacteria and prevent them from multiplying. However, if dormant TB bacteria become active in the body, the person will develop an active TB infection.
- Several factors, such as close contact with people who have active TB, HIV infection, malnutrition, drug use, cancer, diabetes, and a weakened immune system, can influence the progression from latent TB to active TB disease. HIV infection is the strongest known risk factor for progressing to TB disease.
- The tools used for the detection of latent TB cases are the tuberculin skin test (TST) and interferon-gamma release assays (IGRA). However, the TST has low specificity and low sensitivity, as it also shows positive results for those who received the BCG vaccine for TB, while the IGRA is expensive and requires specialized instruments, trained personnel, and laboratories. Aside from sensitivity issues, neither the IGRA nor the TST can reliably differentiate between active TB disease and LTBI, nor can they predict LTBI reactivation.
- The Cy-Tb test is one of the most recent advances in LTBI diagnosis and is a new form of TB skin testing.
- LTBI can be treated to prevent active TB disease.
- TB preventive treatment (PTT) is offered to people who are at risk of developing TB disease. It consists of a cycle of one or more anti-TB drugs. TPT is only given to people who are infected with the TB bacteria or who are at increased risk of developing TB disease.
- LTBI management should include LTBI case follow-up, efficient diagnostic methods, safe and effective treatment, and monitoring.
Knowing these facts will help people living with latent TB infection to receive their treatment at the right time.
Source: IANS
