On the occasion of World Tuberculosis Day, we talked to Dr. Morera Prat, specialist in Pneumology, to find out more about this disease: How is it transmitted? What is its incidence in Spain? What is its diagnosis?
The incidence of tuberculosis in Spain decreases around 10% every year. Tuberculosis is an infectious disease caused by a bacterium, Mycobacterium tuberculosis. Although it mainly affects the lungs, in some cases it can spread or expand to other areas such as the kidney, the meninges or the spinal column.
According to Dr. Morera, this disease provoked “a social fear” that tinged the literature, poetry and music of the 18th, 19th and 20th centuries. Moreover, during the first quarter of the 20th century, 15% of deaths were secondary to tuberculosis. Over the years, tuberculosis has moved to countries with poverty, such as Africa, and has been taught with the carriers of AIDS.
Finally, thanks to the discovery of several drugs, tuberculosis became in the forties and fifties a curable disease.
In 2013, in Spain there were 12 new cases per 100,000 inhabitants. This is slightly higher than in Denmark, the Netherlands and Germany. On the other hand, a little lower than in the United Kingdom and clearly lower than in several European countries. In Romania, for example, there are 85 new cases per 100,000 inhabitants.
The incidence of tuberculosis in Spain falls by about 10% each year.
Symptoms of tuberculosis
Tuberculosis is transmitted through the air, by coughing and sneezing. On the other hand, it is not transmitted by physical contact, nor by sharing cutlery, glasses or clothes.
The main symptoms of pulmonary tuberculosis, which is the most frequent, are fever, tiredness and cough. Tuberculosis of other areas has symptoms specific to each affected organ. The most dreaded type is tuberculous meningitis, which mainly affects children and has very nonspecific symptoms such as severe headache and high fever.
Diagnosis of tuberculosis
Tuberculosis is diagnosed by finding the bacteria in sputum or culture, which generally requires 60 days. To perform the test there must be a previous suspicion, either by occasion of contagion, by school or company check-ups, by suggestive symptoms or by suspicious X-rays.
On the other hand, a positive tuberculin test (or PPD) only indicates previous contact or infection, but does not diagnose current active tuberculosis.
There are relatively recently introduced serological tests that have a similar validity to tuberculin. There are also molecular biology techniques to rapidly identify tuberculosis in sputum, and even drug resistance.
All these tests require specialized laboratories.
Diagnosis of tuberculosis through urine
Dr. Morera explains that there is a new test that diagnoses tuberculosis through a person’s urine. This technique is important because it is non-invasive.
It consists of the detection of a metabolite, lipoaribinomannan, which has proved useful especially in African children who are HIV carriers. For us, it may prove to be a good screening method.
The drawback of this test is that it still has a low sensitivity, around 50%, so new results are needed.