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Epidemiology

Bacillus in the tribe

Tuberculosis is 20 times more common amongst Indians than in the rest of the population.

Paulo C. Basta/fiocruzSuruí village: changes in the lifestyle favor transmission of diseasesPaulo C. Basta/fiocruz

Five hundred years after the discovery of Brazil, the Indians continue to die as a result of diseases that arrived in Brazil with the Europeans. Amongst them, tuberculosis, one of the most fatal. A survey recently concluded by the team of Carlos Coimbra Júnior, from the Oswaldo Cruz Foundation (Fiocruz), in Rio de Janeiro, shows that the number of cases of tuberculosis is about 20 times higher amongst the Suruí Indians, from Rondônia, than in the Brazilian population: 815 cases for each 100 thousand persons, against roughly 40 in 100 thousand in the rest of the population.

“In Brazil, the only group that is similar to the Indians in terms of the incidence of tuberculosis is the prison population”, Coimbra reckons. A sanitarian and anthropologist, for 20 years he has been coordinating a team that includes the physician Paulo César Basta and investigating the quality of life and the health of the indigenous peoples in Rondônia and Mato Grosso. In the last five centuries, tuberculosis has contributed towards devastating the indigenous population, which once had between 1 million and 10 million people at the time the Europeans arrived and today is around 460 thousand individuals, the National Indian Foundation (Funai) estimates.

Possible causes
There are those who suspect that the proportion of cases of tuberculosis is higher amongst the Indians because they are more susceptible to the bacterium, as a consequence of a more fragile immune system. For Coimbra, though, there is insufficient data to confirm the hypothesis. To fill the gap, his team has begun to investigate the immunological and genetic characteristics of these Indians.

Until this answer comes, it is, at least in part, possible to explain the causes of the problem. In the communities accompanied by Coimbra, health suffers a strong influence in the social and environmental context. From the 1980’s onwards, the market economy led indigenous communities to replace their crops of corn and cassava with the commercial planting of coffee, from which they do not always manage to extract enough to survive.

With this transformation and the arrival of the timber companies, Coimbra says, the practice of hunting, fishing and gathering resources from the forest has practically disappeared. As a result, the community has become dependent on industrially-processed and the cases of malnutrition have increased amongst the Suruí children.

Poverty and malnutrition make health deteriorate, but changes in the way of life facilitate the transmission of diseases. “The Suruís no longer live in those big straw huts, today their villages look more like the outskirts of our cities, with crude houses of boards”, says Coimbra. According to the anthropologist, it is possible that the huts, with their large internal space, allowed the air to circulate, reducing the concentration of the bacterium that causes tuberculosis. In turn, the stifling little houses and the high birth rate, which results in large families, may facilitate the transmission of this bacillus, which remains in the air for long periods, in particles produced when a sick person coughs.

But it is not just the insalubrious housing conditions that are responsible for the prevalence of tuberculosis in the indigenous villages, according to a paper published in September in Memórias [Memories], from the Oswaldo Cruz Institute. Genetic analyses of the bacteria present in the phlegm of five Indians with tuberculosis revealed four different strains. These results show that new cases are coming from outside the village, in the frequent contacts that the Suruís maintain in the nearby towns.

A little more than a thousand kilometers from Rondônia, in the Xingu Indigenous Park, in Mato Grosso, for over 40 years the Preventive Medicine Department of the Federal University of São Paulo (Unifesp) has been supplying more than medical treatment to the 14 ethnic groups that live there. The Xingu Project also qualifies indigenous health agents, who act inside the tribes. Even so, according to the 2002 report on the project, the proportion of new cases of tuberculosis per year is high: 263 per 100 thousand inhabitants.

Cultural abyss
Besides the isolation of the villages, another obstacle to the treatment of the Indians is the difficulty of communication. “Indigenous populations have a different notion of temporality; they do not understand the concept of taking a pill every eight hours. For that reason, the indigenous health agents are fundamental intermediaries”, explains physician João Miraglia, from Unifesp’s Indian Medical Clinic and a collaborator of the Xingu Project.

One example of the poor communication between doctors and Indians is the case of one Suruí. An exemplary patient, he said that he was taking his daily medication against tuberculosis and did not miss an appointment at the health center in Cacoal, the town in Rondônia closest to the village. In spite of the medicines, his health worsened. Visiting his house, Basta discovered that he was indeed taking his medicine, but a single pill a day, and not the five prescribed. The error led the patient to develop a lineage of the bacillus that was resistant to the available drugs, which causes concern in the members of the National Tuberculosis Control Program.  This case, Coimbra stresses, demonstrates the urgency of altering the system for treatment. “Brazil has a significant indigenous population, and for that reason has to be creative”, explains the anthropologist, who underscores the need for going beyond epidemiological research.

The information that his group published about the health of the Suruís already represents an advance. “But scientific articles in themselves do not promote change. The information has to be used to improve the treatment and the quality of the services”, claims the researcher. According to Coimbra, it is essential to educate the population and the health professionals, without leaving aside the country’s cultural diversity.

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