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Hearing someone say that they have tuberculosis may be strange. That is because many still believe this is a disease of the past. But according to Julio Croda, Fiocruz researcher and responsible for the project "Tuberculosis control strategies in prisons", it is the infectious and contagious disease that currently kills more than any other disease in the world.

According to Julio, despite affecting the most vulnerable populations, tuberculosis is transmitted through the air. That means that in big cities, in environments with a great circulation of people, there is a great chance of contracting the disease. In the interview that follows, the researcher still explains the relationship between tuberculosis and the current world, and what is the situation of Brazil in this scenario.

Why is tuberculosis so dangerous, and why the attention given to it is still not enough?

Tuberculosis is a contemporary issue in our society, and since 2015, it causes more deaths than Aids. This happens because, generally, poverty levels have increased worldwide, and poverty is directly related to the rates of this disease. Not long ago, the world went through an economic crisis, a series of new conflicts, a refugee crisis, and a mass migration to Europe. All of these economic conditions of impoverishment lead to the resurgence of tuberculosis.

The disease is so neglected because it affects populations that are also neglected, that is, populations that are not visible. People do not listen much about tuberculosis in the mainstream media precisely because it is a disease that affects a more vulnerable population. We can say that in Brazil there are populations where the risk of falling ill with Tuberculosis is 30 times higher than in the general population. Such is the case of those people deprived of freedom, where the number of cases is of 1,500 out of every 100 thousand people, whereas in the general population, we find 30 cases out of every 100 thousand people.

Brazil is responsible for a third of the cases of tuberculosis in America. Why such a large number?

Our Country has 200 million inhabitants, and with the exception of the United States, is the most populated country in America. The fact is Brazil still presents health rates that are very different from those of developed countries, so when taking into account the population size, we present this information: Brazil is found among the 20 countries with the greatest number of tuberculosis cases; however, the incidence is moderate, between 30 and 40 cases out of every 100 thousand inhabitants. Therefore, we are in a pretty favorable position when compared to other countries in Asia and Africa, for example.

The spread of tuberculosis happens through air, and the disease is increasingly resistant to antibiotics. Are new measures being evaluated, for prevention as well as regarding drug resistance?

There is a worldwide increase trend of resistance to antibiotics, and that is also valid for drugs used in tuberculosis treatments. Meanwhile, new drugs are still non-existent. So, why are there resistant forms of the disease? Because of the non-compliance of patients with the appropriate treatment. As long as the patient does not follow the treatment, especially in the early stages, there is a great chance of developing resistant forms, and treatment for such forms is quite complicated. Currently, treatment for resistant forms lasts between 12 and 18 months, and it requires the use of injectable drugs, which directly compromises its success rates.

Nowadays, new clinical trials are being carried out in order to diminish the time and the treatment to 6 months and to avoid the use of injectable drugs. If that happens, we will find many benefits, such as the increase of adhesion and the cure rate, as well as the decrease of transmission of these multi-drug-resistant strains.

According to the World Health Organization (WHO), homeless people are 56 times more likely to get tuberculosis. Additionally, indigenous and prison populations are also more vulnerable to the disease. Why?

In Brazil, there are four population groups that are more vulnerable to tuberculosis: people living with HIV/Aids, people deprived of freedom, the indigenous population and the homeless. When we analyze the impact of each condition in the total number of cases, despite homeless people having the highest rate, this population is still small if we compare it to people deprived of freedom and to those living with HIV/Aids. So, in the context of many countries like Brazil, these two last populations are the ones that contribute more to the general rates of this disease.

Their vulnerability depends on the characteristic of each group. In the case of Aids, this happens because of the cellular immunity problems caused by HIV, which affects the capacity to fight and control the tuberculosis infection. For the other three groups, the reason is the socio-economic conditions and unfavorable living conditions. In other words, it is associated with individual factors that are more frequently found in such population, like drug use, housing, access to diagnostic, among others. In the case of those deprived of freedom, the issue of prison overcrowding has been fundamental for the increased incidence in the last years. All these populations also find difficulty of access to diagnostic, which is a very relevant factor in tuberculosis control.

The "World Tuberculosis Day" was celebrated on March, 24th. How is the current situation of this disease in Brazil and what are the plans for the future?

This is a very important day to emphasize that currently, tuberculosis is the infectious and contagious disease that currently kills more than any other disease in the world, and that an early diagnostic is necessary for an appropriate treatment. In Brazil, we have a 1.5% incidence reduction per year. That means we are way behind what is needed for reaching the goal set by the WHO until 2035 - which is of 10 cases out of every 100 thousand inhabitants.

In addition to the existing available measures, innovations are also necessary. In this respect, Fiocruz and Fiotec play a fundamental role, which is that of fostering and supporting the Ministry of Health in researches that impact directly on interventions in the Single Health System (SUS). An clear example is the research financed by the National Institutes of Health (NIH), "Tuberculosis control strategies in prisons," in which I am the main researcher in Brazil, and Jason Anderson is the main researcher at Standford University. In this project, we are screening, offering molecular tests and x-ray exams for all the inmates of two prisons in the State of Mato Grosso do Sul, in Campo Grande and in Dourados. We will offer these exams for two and a half years, twice a year, and then, based on the data generated throughout the research, we will create mathematical models that help the Ministry of Health to establish which intervention is more appropriate for tuberculosis control among the populations deprived of freedom.