Progression of Chagas’ Disease

Carlos Chagas discovered the symptoms and progression of Chagas’ disease. Figure 8 illustrates how Chagas’ disease progresses, which is a complex and in part unresolved issue. Primary Chagas’ disease refers to the acute infection stage, which may not be clinically apparent, with about 25 percent of infected patients indicating it (see Appendix 9). If apparent, it is characterized by inflammation that may include fever, general malaise, swelling and soreness of the lymph nodes and spleen, and by Signo de Romaña, severe swelling around the eye. People die or suffer permanent damage during the acute phase; those who survive have classic chronic or tertiary Chagas’ disease.

Infected victims pass into early latent Chagas’, which is asymptomatic. Latent Chagas’ offers several possibilities: 1) the infection is arrested at this stage, 2) it develops later to late latent Chagas’ with minor clinical findings, or 3) it develops into classic chronic (tertiary) Chagas’ disease. Those with minor clinical findings progress to either early latent arrested (secondary) Chagas’ or classic chronic (tertiary) Chagas’.

A certain number of patients live out their lives in the early latent arrested phase, with no noticeable symptoms, except perhaps fatigue. As mentioned, one acute patient of Carlos Chagas in 1909, Bernice, lived past the age of seventy and was checked annually, with no symptoms of the disease ever being manifested (Lewinsohn 1979:519). However, in many instances, the disease culminates with classic chronic symptoms of tertiary Chagas’heart disease and enlarged colon and esophaguswhich if untreated result in death. There is no known cure for the chronic phase.

Chagas’ disease is closely related to the immune system. Its progression varies greatly with the immunocompetence of each individual. Bolivians suffer so greatly from it in part because many are malnourished and infected with other diseases (see Appendix II).

At the Brazilian National Academy of Medicine’s session on April 22, 1909, Oswaldo Cruz read Chagas’ work entitled “A New Human Trypanosomiasis.” Cruz referred to the new disease as American trypanosomiasis to distinguish it from African trypanosomiasis, but American trypanosomiasis was soon known as Chagas’ disease (Kean 1977). Shortly after the reading of the paper, Cruz and a group of distinguished physicians traveled to Lassance to visit Chagas at work. Miguel Couto described the visit:

Carlos Chagas was waiting for us with his museum of laboratory items. Examination between cover‑glass and slide revealed the raritiesseveral dozen patients of all ages, some idiots, others paralytics, others heart cases, thyroids, myxedemics and asthenics. Microscopes were scattered all over the tables showing trypanosomes in movement, or pathological anatomic lesions. In the cases were animals experimentally infected and jars full of triatomines in all stages of development. Every item of this demonstration was carefully examined by us. The doctors gathered there, undisputable authorities in their fields… had nothing to deny or add to the analysis of the symptoms or their interpretations… On that day it was up to me to give a name to those traditional diseases of the Minas backlands, which were now unified as one disease with cause and development clearly established. To name it after only one of its symptoms would be to limit its description, and to name it for all its symptoms would be impossible… And so, at dinner, while toasting Carlos Chagas, I… chosen because of my age, standing with Oswaldo Cruz on my right and surrounded by the men most representative of Brazilian medicine of that era, with gravity equal to a liturgical act in our religion, such as a baptism, gave the name of Chagas’ Disease to that illness…in the name of the entire delegation (Couto, in Kean 1977).

^{Figure 8.}

^{Progression of Chagas’ disease. (From Jared Goldstein, “Darwin, Chagas’, Mind, and Body,” Perspectives in Biology and Medicine 32, no. 4 ([1989]:595.)}

Carlos Chagas died in 1933 of angina pectoris as he was looking through a microscope into the universe of parasites. A year before his death, he optimistically spoke to a class of graduating physicians: “Gentlemen, the practical applications of hygiene and tropical medicine have destroyed the prejudice of a fatal climate; the scientific methods are prevailing against the sickness of the tropics” (Kean 1977). On a less optimistic occasion, he remarked, “This is a beautiful land, with its tremendous variety of vegetation. Nature made animal and vegetable life stronger and thus created conditions which bring sickness and death to the men who live here” (Chagas Filho 1993).

Since Carlos Chagas’ amazingly rapid discovery of it in 1909, research concerning this disease has been slow. After Chagas discovered Trypanosoma cruzi, the disease was not described until ten years later and was not recognized as a serious health problem in Brazil for another forty years. Other countries of Latin America have been even slower in recognizing the problem, with Bolivia beginning in 1991. The first and only drugsnifurtimox and benznidazolefor treatment did not appear until 1970 and then met with only partial success. Discovering disease is only a short first step toward treating and preventing it.