Is latent tuberculosis contagious?

Tuberculosis has 2 forms of infection: the latent and the active infection. What is the difference between the 2 forms? And is latent tuberculosis contagious?

Forms of tuberculosis infection

Latent tuberculous infection

It means that the patient had got the infection already but not showing any manifestations of the disease.

It is not diagnosed except accidentally during screening for the disease.

The patient with latent infection may show the first manifestation of tuberculosis 2 years after having the infection.

Active tuberculous infection

The patient will show manifestations of active infection both the general manifestations for instance fever, chills, fatigue and night sweating.

In addition, the patient will show positive investigations results such as cough, bloody sputum, difficulty breathing as well as pain in the chest.

Active tuberculosis is contagious i.e.: can transmit the infection to healthy people.

Is latent tuberculosis contagious?

No. Latent tuberculosis is not contagious i.e.: Patients with latent infection of tuberculosis can’t transmit the infection to others.

The immune system can contain the infection but is unable to eradicate it. However, the load of infection is not permitting its transmission of infection.

Diagnosis of latent infection with TB

It gives a positive tuberculosis test, whether the skin tests (Mantoux test) or the blood test.

The test doesn’t differentiate between the latent and active infection. It just means that the bacteria had entered the body and stimulated the immune system to produce a response.

Every other investigation will give negative results i.e.: will be normal studies. For example, sputum examination and chest X-ray.

Risks of latent tuberculosis

The bacteria are causing some harm to the lungs, later on, the patient may show manifestations of active TB or reactivation of infection.

Treatment of latent tuberculosis

Latent tuberculosis infection should be treated in order to avoid its complications, even if he is not showing symptoms or signs.

It needs medical supervision in order to follow up on the liver condition for fear of the side effects of TB treatment.

The patient should visit the physician once monthly to check the patient for progression and side effects if any.

The treatment involves using one antituberculous antibiotic for 9 months. Another regimen is to use 2 antibiotics for 3 months.

The most effective antituberculous antibiotic is isoniazid and fortunately, it is effective in the treatment of latent TB.

Another effective antibiotic is rifampicin which is used as a second choice treatment for the latent infection.

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