Experience in diagnosis and treatment of Chagas disease in Brazil


Dr Mariana Margarita Martínez Quiroga – infectious disease specialist - Hospital Regional do Baixo Amazonas (HRBA), Santarém, Pará, Brazil.

Epidemiological situation in Brazil

  • The Brazilian Ministry of Health estimates that between 1.9 and 4.6 million people are infected with T. cruzi in Brazil, which means that between 1% and 2.4% of the population would be infected.
  • Chagas disease is one of the four leading causes of death from infectious diseases in Brazil, and one of the most neglected diseases.
  • Its diagnosis and treatment continue to be a great challenge in endemic regions. Therefore, Chagas disease-related mortality is high.
  • Oral transmission is the predominant transmission route in Brazil, but vector transmission is also present, mainly in the Amazon region.

According to the Brazilian Ministry of Health, from 2010 to 2020, 2777 cases of acute Chagas disease were diagnosed and notified in Brazil. Of these cases, 85% were detected in the North region, mainly in the state of Pará, with 1996 notified cases.  

Why does this happen mainly in the North region?

On the one hand, this can be explained from a geographic perspective and the characteristics of those cities. They are near the Amazon River and many of the houses are located inside the pristine forest, surrounded by palm trees, which are known to be a natural habitat of triatomines.

On the other hand, the region has the lowest health care service coverage. This is one of the areas with the lowest density of services of the Family Health Strategy, the name given to the Primary Health Care Centres in Brazil. Only 19% of the municipalities have a health post and in 30 of them there is not a single post. In turn, the region has the lowest rate of hospital beds per inhabitants of Brazil (two every one thousand inhabitants), which also explains the high morbidity and mortality.

Oral transmission

Two modes of transmission occur in these domiciles: vectorial and oral. Regarding the latter mode, when the Amazon River level drops and there are no fish available, people feed on wild animals they hunt, such as coati, armadillo, monkey, and deer. Moreover, there is no power supply in these areas. Therefore, people cook using salt or hang the meat in the sun, which is usually known as “charqui” (salty beef) in northern Argentina. This method does not ensure the elimination of T. cruzi. 

 Furthermore, fruits like açaí used for self-consumption are not subjected to a bleaching process to eliminate triatomines. By contrast, the shops that sell this fruit apply this process due to sanitary surveillance.

Protocol in case of a suspected case of Chagas disease

We have a national Protocol that provides guidelines to be followed if there is a suspected case of Chagas disease, as well as for diagnosis or treatment. The protocol indicates that, in every suspected case, the presence of T.cruzi in peripheral blood should be confirmed immediately and, at the same time, a serological test through three methods should be requested. According to this manual, this could be done in any Basic Health Unit or at the Diagnosis and Treatment Units. However, this is not the case. At the Basic Health Units this diagnosis is not available, there is no access to those tests. This means that we must refer the patient to a Diagnosis and Treatment Unit. The tests do exist, they are of easy access, but, anyway, we do not have the possibility of making the diagnosis when there is a suspected case. Regarding the serological tests, in Santarém (Pará) we do not have the resources necessary to do them in the Municipality. We must send them to LACEM, a central laboratory in Belem, 700 km away from my city. Moreover, samples are transported once a week and the result is available 30 and 60 days later, hindering early diagnosis.

If the test results positive, the patient is referred to a Reference Service and the epidemiological and sanitary surveillance of the Municipality is activated; thus, active search for the transmitting insects and for other symptomatic people is initiated. In turn, health education and spraying of intra- and peridomiciles are provided.

Regarding treatment, all the acute cases are treated; chronic indeterminate cases or cases with digestive involvement are put into consideration due to the age of patients, and in cases of advanced cardiopathy, Brazil does not indicate treatment.