Speaking to Poland's PAP news agency, pulmonologist Dr. Ewa Malinowska said that infection with tuberculosis bacteria does not automatically mean a person will fall ill.
She said people usually become sick when their bodies are already weakened.
"Becoming infected with the tuberculosis bacillus does not mean you will immediately develop tuberculosis," Malinowska said. "Those who fall ill are most often weakened, poorly nourished, with reduced immunity."
She listed HIV infection, drugs that suppress the immune system, organ transplants and some rheumatological diseases as known risk factors.
According to data from the Institute of Tuberculosis and Lung Diseases in Warsaw, around 4,200 tuberculosis cases were recorded in Poland last year.
Malinowska said this places Poland among countries with a low incidence of the disease.
At the same time, she noted that the World Health Organization (WHO) counts tuberculosis as one of the most common infectious diseases worldwide.
More than 10 million people develop it every year and over 1 million die, including about 1.25 million children under 15.
Experts warn that a growing share of these cases involve drug-resistant strains, including extensively drug-resistant tuberculosis, or XDR-TB.
XDR-TB is a severe form of the disease that is resistant to at least the two most effective first-line tuberculosis medicines, isoniazid and rifampicin.
It is also resistant to any fluoroquinolone antibiotic and at least one of the injectable second-line drugs that doctors use when standard treatment fails.
Health specialists say this kind of resistance often arises when tuberculosis treatment is managed poorly, for example when patients take medicines irregularly or stop therapy too soon.
Poland continues to vaccinate newborns with the BCG vaccine on the first day of life. This vaccine does not completely prevent infection, but it protects young children from the most severe forms of the disease, such as tuberculosis meningitis and so-called miliary, or widely spread, tuberculosis.
Malinowska explained that tuberculosis spreads differently from viral infections such as seasonal flu and COVID-19, which is caused by the SARS-CoV-2 virus.
"Even if a person has contact with someone who is excreting tuberculosis bacteria and becomes infected, the risk of developing the disease over their entire lifetime is about 5 percent," she said.
Whether someone becomes infected depends on the type of contact. Close, usually family contact carries a higher risk, while occasional encounters, for example at work, are less dangerous.
However, people who know they have spent time around a contagious patient are offered preventive testing to see if infection or disease has developed, even if they feel well.
To investigate such contacts, doctors can use blood tests known as interferon-gamma release assays, or IGRAs, which detect an immune reaction to tuberculosis bacteria.
They may also use older skin tests with tuberculin, now applied less often, and chest X-rays to look for signs of disease in the lungs.
Malinowska warned that some symptoms of tuberculosis overlap with those of lung cancer. Alarming signs include night sweats, a cough that lasts for more than eight weeks, and coughing up blood.
"Patients with these symptoms require very thorough diagnosis," she said. Confirmation of tuberculosis usually involves laboratory analysis of material from the respiratory tract, such as sputum produced by the patient or samples collected during bronchoscopy, a procedure in which doctors examine the airways with a thin tube.
Tuberculosis can also affect organs outside the lungs. When doctors suspect so-called extrapulmonary tuberculosis, they may send other samples for testing, including fluid from the chest cavity, urine or cerebrospinal fluid from around the brain and spinal cord.
Once the disease is confirmed, the patient faces a long course of treatment that lasts at least six months.
"The most intensive phase of treatment, which lasts about two months, takes place in hospital," Malinowska explained.
When patients are no longer contagious, they can often continue therapy at home, as long as doctors are confident that the medicines will be taken exactly as prescribed.
"We have effective anti-tuberculosis drugs and most patients can be fully cured," she said. "The problem is strains that are resistant to medicines. The most important cause of drug resistance is irregular, interrupted treatment.”
Patients in difficult social situations, such as people experiencing homelessness or alcohol dependence, often remain in hospital for the entire treatment period because there is no guarantee they will continue therapy without medical supervision.
In Poland, tuberculosis is treated in specialist hospital wards, and Malinowska estimated that only "several dozen” doctors focus on this disease in everyday practice.
"Doctors of every specialty can encounter both pulmonary and extrapulmonary tuberculosis, which is why knowledge of its symptoms is so important," she said.
(rt/gs)
Source: PAP