Is tuberculosis contagious?

Written by Yuan Lin Yan

Infectious Disease

Updated on September 27, 2024

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Not all cases of tuberculosis are infectious. Some tuberculosis cases are infectious in the early stages but become non-infectious after proper treatment. Patients with open tuberculosis are highly contagious because their sputum contains tuberculosis bacilli. These bacilli can be released into the air through coughing, sneezing, laughing, or loud speaking, and can cause infection when inhaled by others. Some tuberculosis patients do not have detectable bacilli in their sputum, and their infectiousness is relatively much lower.

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Written by Wang Xiang Yu

Pulmonology

1min 5sec

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How is tuberculosis transmitted?

How is pulmonary tuberculosis transmitted? First, we need to know the pathogen of pulmonary tuberculosis, which is the tuberculosis bacillus. Tuberculosis bacillus is a type of bacterium that can live in our surrounding environment. Pulmonary tuberculosis also needs a source of infection, that is, a patient carrying the tuberculosis bacillus. The most common source of tuberculosis infection is usually patients with secondary pulmonary tuberculosis. Then, its mode of transmission mainly includes coughing, sneezing, laughing, and talking loudly, which can release the tuberculosis bacilli from the patient into the air, spreading them through droplets. Droplet transmission is the most important route for the spread of pulmonary tuberculosis. Additionally, pulmonary tuberculosis can also be transmitted through other routes such as the gastrointestinal tract or the skin, although these methods of transmission are less common.

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Written by Li Jiao Yan

Neonatology

1min 1sec

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Does the BCG vaccine prevent tuberculosis?

The BCG vaccine primarily prevents infection by the tuberculosis bacillus, so it can prevent pulmonary tuberculosis. The protective effect of the BCG vaccine is mainly achieved through inducing a cell-mediated immune response. After vaccination, a primary infection is formed, which is processed by macrophages that transmit the antigen information to immune-active cells, leading to the differentiation and proliferation of T cells and the formation of sensitized lymphocytes. When the body is re-infected with the tuberculosis bacillus, the macrophages and sensitized lymphocytes are activated, causing a specific immune response in the body, thereby resisting the infection by the tuberculosis bacillus. Therefore, the BCG vaccine mainly prevents pulmonary tuberculosis.

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Written by Wang Xiang Yu

Pulmonology

46sec

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Can tuberculosis relapse?

Tuberculosis can relapse, and the answer is definitely yes. In clinical practice, we see many patients who have had tuberculosis and, years later, experience a recurrence of the disease, even multiple recurrences. However, the probability of this is generally not high. As long as everyone follows the doctor's instructions for standard anti-tuberculosis treatment and completes the full course of treatment, most patients can be cured. However, there are a few people whose treatment process is not standard, or who stop taking their medication on their own, and these actions can increase the risk of tuberculosis recurrence.

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Written by Wang Xiang Yu

Pulmonology

1min 14sec

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Is tuberculosis easily contagious?

Whether tuberculosis (TB) is easily transmitted primarily depends on the source of infection, which refers to the TB patients and the amount of Mycobacterium tuberculosis in their sputum. If TB bacilli can be detected in their sputum, and the quantity is substantial, then their infectiousness is indeed higher. However, if the TB patient has undergone treatment, or if there are only a few TB bacilli in their sputum, or none at all, then their infectiousness may not be as significant. The second factor is the mode of transmission, which mainly occurs through the respiratory tract. If TB patients can be isolated timely, or if they wear masks, and their sputum is properly managed, for example by wrapping the sputum in paper and burning it, then they are less likely to transmit the disease to others. TB generally involves susceptibility issues; even if someone has been vaccinated with BCG or the TB vaccine, they can still be reinfected. Therefore, controlling these three transmission pathways is essential to minimize the risk of contracting TB.

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Written by Xiong Hong Hai

Infectious Disease

39sec

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Is tuberculosis serious?

Tuberculosis is a relatively serious disease, but if it is treated and managed promptly in the early stages, it often can be brought under control and most cases can completely recover. If the disease is allowed to progress unchecked, it can develop from ordinary tuberculosis into an especially severe form of the disease, even endangering life and leading to extrapulmonary tuberculosis. The severity of tuberculosis depends largely on the extent of damage to the lungs and whether there is extrapulmonary tuberculosis. Once tuberculosis is confirmed, scientifically sound and appropriate anti-tuberculosis treatment should be undertaken.