Tuberculosis is an infection caused by the bacterium (germ) Mycobacterium tuberculosis complex. It can affect commonly the lungs but otherwise can affect any part of the body. Its incidence in Malta remained stable over the last few years. TB can be contagious from people who have active pulmonary TB.
Reservoir
Mainly humans, rarely diseased cattle, badgers, swine and other mammals.
Incubation Period
- From infection to the primary lesion or significant tuberculin reaction: 4 –12 weeks.
- The risk of developing progressive pulmonary or extra-pulmonary TB: within 1 – 2 years Latent infection may persist for a lifetime.
- Patients infection with HIV, shorten the interval and increase the risk to develop TB disease.
Signs and Symptoms
Since TB can affect any part of the body, symptoms vary and the initial infection can pass unnoticed.
Commonest symptoms include:
- Cough – lasting more than 3 weeks with or without blood streaked sputum
- Shortness of breath
- Fever and night sweats
- Loss of appetite and weight
- Malaise – feeling generally unwell
- Extreme fatigue and tiredness
- Chest pain on breathing (pleurisy)
Diagnosis
TB can be diagnosed by:
- Clinical presentation
- Chest X-Ray (sometimes CT scan may be required)
- Sputum culture and staining to test for Mycobacterium tuberculosis
Who can get TB?
Anyone can get TB but it is commoner in overcrowding or sub-standard housing and malnutrition. TB is caught when a person breathes the bacteria after someone for example sneezes, following prolonged contact with a patient who is suffering from Tuberculosis. Kidney tuberculosis can be infectious from urine.
People who are at a greater risk of catching the disease include:
- Those who travel to countries where TB is common
- People who abuse of alcohol or drugs
- Persons whose immune system is weakened ex. HIV, on immunosuppressants
- Close contacts of an infectious cases
- Young children and elderly people
- Health professionals
- Patients suffering from diabetes
Treatment
Antibiotics prescribed by medical doctor (isoniazid, rifampicin, pyrazinamide and ethambutol – for the first two months and then continuing with isoniazid and rifampicin only for the next 4 months).
Treatment is generally at home – hospitalization may be required in patients who are very ill or thought to be very infectious.
Control and Prevention
BCG immunisation at the age of 12-14 years increases the person’s immunity to TB. Re-immunisation is not recommended. Vaccination for people over 45 is not recommended unless they are in a high-risk group.
Before the vaccination is given, a Mantoux test is carried out to check for previous exposure to the TB bacterium and immunity. This involves injecting the tuberculin protein into the skin and the result can be reviewed after 48 hours. If the test is positive, i.e. a raised red reaction on the skin, the vaccination is not given.