By: Mariana Mendonça Batista (IC-FAPERJ), Nayane Abreu do Amaral e Silva (Doutoranda PPGQ-UFF) e Drª. Daniela de Luna Martins (PPGQ-UFF).
In 1909, the Brazilian public health physician Carlos Ribeiro Justiniano Chagas (Figure 1, [1]) discovered American trypanosomiasis or Chagas disease (CD), the name by which the disease is known in his honor..
Figure 1 - Carlos Justiniano Ribeiro Chagas (1879-1934) [1]
CD is a tropical disease found mainly in 21 countries in Latin America. The protozoan Trypanosoma cruzi (T. cruzi) is the causative agent of Chagas disease. [2]
Figure 2 - Trypanosoma cruzi [3]
The disease is transmitted through vectors infected with T. cruzi, popularly known in Brazil as barbers (triatomines) (Figure 3). [4]
Figure 3 - Barbers [4]
When the barber contaminated with T. cruzi bites an individual, it releases feces that contain the protozoan. When the person scratches the injured area, the protozoan is dragged there and can enter the body through this point. Penetration can also occur through the eyes, nose, mouth or fresh wounds. In addition, CD transmission can occur in other ways, such as transmission by blood transfusion, congenital transmission from mother to child through the placenta, ingestion of contaminated meat and accidentally in laboratories. [5,6] CD has an acute phase and a chronic one. In the acute phase of CD, the initial phase, the main symptoms are: fever, malaise, lack of appetite, edema located in the eyelid or in other parts of the body, enlarged spleen, enlarged liver and cardiac disorders. In children, the condition can worsen and lead to death. It is common that at this stage there are no symptoms of the disease. Even in the chronic phase, many patients can spend a long period, or even their entire life, without showing any manifestation of the disease. In other cases, the disease causes damage to many systems, especially to digestive and cardiac systems. [5, 6] Heart problems caused by CD are the leading causes of death among infected people. [3] The main ways to control the transmission of the disease are early diagnosis and treatment. Another effective preventive action consists of controlling the proliferation of triatomines using insecticides. An important measure is to improve the structure of mud houses, through plastering and closing cracks and crevices that are used as shelter by "barbers" during the day. In addition, there are also useful prevention measures: using screens on doors and windows, periodically cleaning houses and their surroundings; spread the basic knowledge about the disease, the transmitter and preventive measures to friends, relatives and neighbors, and refer insects suspected of being "barbers" to the nearest health service. [5,6]
Regarding the treatment of CD, we can say that we have a critical situation. That's because the only drugs available for the treatment of the disease are Nifurtimox and Benznidazole (Figure 4). These drugs are effective only in the acute phase. When treatment is started early in the disease, the aim is to cure the infection and prevent damage to the heart and other organs. [4-7] In addition to their low efficiency, when administered in the chronic phase of CD, both drugs generate severe side effects, for example: peripheral neuropathy, anorexia, nausea, leukopenia, vomiting, headache, abdominal pain, among others. [7]
Figure 4 - Chemical structures of benznidazole and nifurtimox
References
[1] Rebeca Fuks in ebiografia.com. "Os 11 mais importantes cientistas brasileiros." Available: https://www.ebiografia.com/cientistas_brasileiros_mais_importantes/. Accessed: July 28, 2021.
[2] a) Dias, J. C. P.; Ramos Jr. A. N.; Gontijo, E. D.; Luquetti, A.; Shikanai-Yasuda, M. A. et al. Rev. Soc. Bras. Med. Trop. 2016, 49, 3. b) World health organization. Available: https://www.who.int/news-room/facts-in-pictures/detail/chagas-disease. Accessed: June 6, 2021.
[3] I. C. M. Mendes. Available: https://pebmed.com.br/doenca-de-chagas/. Accessed: July 24, 2021.
[4] P. Pinheiro. Available: https://www.mdsaude.com/doencas-infecciosas/parasitoses/doenca-de-chagas/. Accessed: July 24, 2021.
5- a) Dias, J. C. P.; Coura, J. R. Clínica e terapêutica da Doença de Chagas: uma abordagem prática para o clínico geral, Rio de Janeiro: Editora FIOCRUZ, 1997, 486p. b) Shikanai-Yasuda, M. A.; Carvalho, N. B. Clin. Infect. Dis. 2012, 54, 845. c) Nóbrega, A. A.; Garcia, M. H.; Tatto, E.; Obara, M. T.; Costa, E.; Sobel, J.; Araujo, W. N. Emerg. Infect. Dis. 2009, 15, 653.
6-a) Brazilian Health Ministry site. "Doença de Chagas." Available: https://antigo.saude.gov.br/saude-de-a-z/doenca-de-chagas. Accessed: June 06, 2021. b) Brazilian Health Ministry site. "Doença de Chagas." Available: http://bvsms.saude.gov.br/dicas-em-saude/2057-doenca-de-chagas. Accessed: June 06, 2021.
7- a) Altmann, E.; Aichholz, R.; Betschart, C.; Buhl, T.; Green, J.; Lattmann, R.; Missbach, M. Bioorg. Med. Chem. 2006, 16, 2549.b) Salomon, C. J. J. Pharm. Sci. 2012, 101, 888.