CHAPTER SIX

Bertha: Mal de Corazon

Bertha (a pseudonym) is a resident of La Paz, Bolivia, who suffers chronic heart ailments from Chagas’ disease. Bertha’s medical history provides insights into the natural history of Chagas’ disease. As a child in the 1930s, Bertha was bitten by vinchuca bugs and infected with Trypanosoma cruzi in Tupiza, a small rural village in Bolivia. Later, as a mother with four daughters, she moved to La Paz after being abandoned by her husband. She made a meager living sewing for wealthy people. Late in 1974 she suffered heart disease and was diagnosed with Chagas’ disease. Presently, at age sixty‑one, Bertha still sews dresses but also receives additional income from her married daughters.

Bertha is a small slender lady with sparkling dark brown eyes. She speaks Spanish, dresses in western‑style clothes, and is of the mestizo class, in contrast to the cholo class, those who maintain Aymara and Quechua identity. Bertha narrated the following account to Dr. Pedro Jáuregui, her personal physician, on July 22, 1991, illustrating the effects of chronic Chagas’ disease.

I was raised in a community of Tupiza, a valley of Potosí. We always traveled to the country. In the village the vinchucas entered the houses. I didn’t know anything about them when I was a child. Vinchucas were an inch long with wings, some were brown, brown‑black, and they usually bit us. They laid their eggs, and we played with their eggs. At night without electricity we could feel them, we would pull off their heads. This was the way to kill them.

At other times I awoke with eyes swollen, then I put a little tea water and some leaves over the swelling. It was not a large swelling.

We didn’t have fear of them. As a child, I played with them, putting their eggs in a basket as if they were chicken eggs. I didn’t know that this bug was dangerous. We had sheep, chickens, and corrals where vinchucas would dig their nests. Another insect was chinchina. There were both types of insects because we lived in the valley. My father was an administrator in a mine so he traveled frequently. I think that vinchucas (barbeiros ) inhabited most of the houses.

I left Tupisa when I was twenty years old and moved to La Paz. And until the age of forty‑four I was a healthy person, going up and down the hills. I had no idea that I was sick with Chagas’ disease until 1974 when I felt fatigue, although before [that time] I had some allergies when I ate lentils. I began to get a swollen throat and spit blood. I didn’t know what it was. I didn’t feel anything for forty years. I didn’t have any idea that this was caused by vinchucas. I would get tired, fatigued, and experienced dizziness and many fainting [spells] around 1974. I was without a husband and when I knit alone, I experienced fainting. My daughter who slept at my feet felt that I was trying to kick her. This fainting continued for a year, and the next year I had more severe fainting, and the next year I was found laying in my room with another stroke after I had arose to get a drink of water.

After my children found me, they insisted that I see a doctor. Dr. Jáuregui hospitalized me. He felt my pulse which was very low. He suspected Chagas’ disease and had me undergo a test [xenodiagnosis] where they determined it was Chagas’ disease with the same bites of [uninfected] vinchucas. I could feel the bites, and after they itched and burned a bit.

Only then did I learn about Chagas’ disease that was caused by vinchucas. I thought my sickness was from overwork and problems with work (Bertha interview 7/22/91).

After Bertha was hospitalized, Dr. Jáuregui examined her and found a low pulse. An electrocardiogram indicated that she was suffering from arrhythmia (irregular heartbeats) and bradycardia (slow heartbeats). X‑rays indicated a normal‑sized heart, not one enlarged as in cardiomegaly. Jáuregui suspected that trypanosomes had affected the nervous system of the heart and that Bertha had developed a heart block, a potentially fatal complication. He believed that a heart block is more deadly than cardiomegaly, a more frequent cardiac form caused by lesions.

Heart block occurs when there is blockage in the conduction system of the heart. The sinoatrial (SA) node is a small control center near the top of the heart that emits signals to the atrioventricular (AV) node, which regulates heartbeats. It is similar to the electrical control harness in an automobile that regulates electricity to the horn, lights, and radio. If one of these wires is cut, for example, then the horn will not work. In Chagas’ disease, heart block occurs when there are lesions in the conduction system causing the heart’s beats to be slow.

Because Bertha grew up in an endemic chagasic area, Jáuregui suspected that T. cruzi were weakening her heart, and he used xenodiagnosis to determine if T. cruzi could be found in her blood. For Bertha’s exam, forty uninfected vinchucas were divided into two small jars. The jars were placed underneath Bertha’s arms so that the bugs could draw her blood. This continued for one‑half hour, until all the bugs had ingested from 7 to 8 milliliters of blood. Bertha later complained about the bites and itching, and, when her daughter was later suspected of having Chagas’ disease, Bertha discouraged her from this exam. Results for Bertha tested positive, so Jáuregui began treating her with benznidazole, diuretics, and tranquilizers.

By 1980 Bertha’s heart rhythm had worsened, so Jáuregui implanted a pacemaker that same year, which was replaced in 1991. The pacemaker regulated her heartbeat and the fainting spells diminished, so Bertha was able to resume her work as a seamstress, although she suffered from minor fatigue when she climbed the streets of La Paz at 12,000 feet.

Most likely as a result of congenital infection, two of Bertha’s daughters also have heart problems. The eldest daughter, now thirty‑eight, was born with heart trouble and suffers continual fatigue. After Bertha learned that Chagas’ disease was congenitally transmitted, she encouraged her daughter to undergo xenodiagnosis. Dreading being bitten by vinchucas, the daughter refused testing. She is afraid because the bites are irritating; alternative serological tests, such as ELISA Immunosorbent, are available in La Paz and are painless except for the drawing of blood. The second daughter has tachycardia and was tested by xenodiagnosis, with negative results (see Appendix 12).

Dr. Jáuregui has treated the symptoms of many patients suffering from heart diseases caused by chronic Chagas’ disease in the Thorax Hospital in La Paz. This hospital was built earlier this century and features high ceilings, tile floors, and tall steel beds, reminiscent of the nineteenth century when some diseases were believed to be caused by emanations from the earthmiasma theory. Jáuregui has claimed no cures for chronic Chagas’ disease and only treats its symptoms, as in the case of Bertha. As Jáuregui described it in an interview on July 19, 1991:

T. cruzi are muy listo (“shrewd critters”)! They circulate in the blood as little as possible, only to be transmitted. They inhabit cells of heart and intestines, vital areas where, to kill them, you have to destroy the organs. All I can do is help patients live a little longer by treating their symptoms. There is no cure for chronic Chagas’ disease.

Bertha’s case history is illustrative of that of many Bolivians who suffer cardiac problems from chronic Chagas’ disease. Ventricular tachycardia frequently occurs among patients of La Paz such as Bertha and is perhaps related to hypoxia (low oxygen) stress. La Paz is situated on slopes with elevations ranging from 11,000 to 12,000 feet. Infected chagasic patients continually climb up and down those slopes in the course of daily life, and for those with heart disease this is difficult and dangerous. Andeans are traditionally renowned for their strong hearts, extra lung capacity, and numerous red blood cells.

Until the recent epidemic of Chagas’ disease in Bolivia, heart disease was not considered the killer there that it is in the United States. However, with the increasing number of chronic chagasic patients, recent Bolivian studies indicate increasing electrocardiographic abnormalities characteristic of Chagas’ disease‑related heart disease. Jáuregui and Casanovas (1987:30‑33) observed a total of 4,108 patients throughout Bolivia and found 853 (20.8 percent) with cardiac abnormalities, out of which 436 (10.6 percent) were infected with Chagas’ disease. Pless and colleagues (1992) did a clinicoepidemiological study in the remote rural village of Tabacal in southcentral Cochabamba, Bolivia. They examined 153 out of 160 villagers for signs of Chagas’ disease and found that 116 people (76 percent) tested positive. The people infected with T. cruzi were 3.5 times more likely than uninfected people to have signs and symptoms of heart failure and nine times more likely to have electrocardiogram (ECG) abnormalities. Some 33 percent of ECG conduction defects occurred in adults over thirty‑five years of age. Tabacal is similar to hundreds of other villages in southcentral Bolivia, which suggests that heart disease could be a major public health problem in this area (Pless et al. 1992, Weinke et al. 1988; see Appendix 10: Chronic Heart Disease).

Altitude appears to affect the manifestations of chronic chagasic heart disease. The lower levels of oxygen characteristic of high altitudes (hypoxia) place additional stress on chronic chagasic patients emigrating from lower to higher regions of the Andes. Patients with heart disease in La Paz are at greater risk of mortality than those at lower levels. The aerobic effect of living at high altitude, which traditionally endows Andeans with strong hearts, is counterproductive to individuals suffering with hearts afflicted with T. cruzi.

Therapeutically, patients with chronic Chagas’ disease stand a better chance of living longer at lower altitudes if they can avoid vinchuca bites, which intensify parasitic infestation of the victim’s body; furthermore, Trypanosoma cruzi has different strains, or zymodemes, which hypothetically possess different clinical manifestations (see Appendix 2: Strains of Trypanosoma cruzi ). One advantage, already discussed, is that the victim is not likely to suffer another acute phase, which often is deadly.

Dr. Toro Wayar has studied and treated patients with chagasic heart disease in Sucre, Department of Chuquisaca, Bolivia, where he practices as a cardiologist and is director of the Centro de Investigación y Diagnóstico de la Enfermedad de Chagas‑Sucre.[33]The Department of Chuquisaca is heavily infested with triatomine bugs and has a high number of infected chagasic patients. For eight years, Dr. Wayar and his staff have performed clinical and electrocardiographic studies of patients either diagnosed with or suspected of having Chagas’ disease. The following are excepts from an interview with Dr. Wayar on June 20, 1991:

The majority of our patients have positive serological indicators that they are infected with Chagas’ disease but totally lack clinical indicators by radiology or electrocardiography. We refer to these patients as infectados chagasicos [people infected with Chagas’ disease]. They become aware of being infected when they are examined for other reasons or they realize they have lived in endemic chagasic areas and want to see if they are infected.

A minority have clinical symptoms discovered in the cardiovascular system. They could have alterations determined by x‑ray in the size of the heart or alterations in the heart rhythm determined by electrocardiogram. Concerning alterations of the heart size, when trypanosomes settle in the heart, they could affect all heart muscles, causing chronic inflammation of the myocardium [myocarditis]. The heart becomes structurally disorganized in all the muscular fibers; it increases in size and presents different degrees of malfunctioning, depending upon the grade of increase, which can be anywhere from two to three times its normal size. But this is infrequent because the person seldom survives to this stage.

The more common type of alteration is found when trypanosomes damage the electrical system of conduction of the heart, which controls the number and intensity of heart beats. Trypanosomes could alter any sector and cause many variations in the form of arrhythmias. This is a characteristic particular to chronic chagasic patients. Arrhythmias range from very light to very severe, which can cause sudden death (muerto subito). Treatment for these patients is limited to resolving cardiac problems, with rather unsuccessful treatments for ridding patients of trypanosomes. (Toro Wayar, interview 6/20/91.)

Dr. Wayar questioned the fact that trypanicides were able to rid chagasic patients of trypanosomes, and there is considerable debate concerning this. Even if the patient can be rid of T. cruzi, that would not eliminate the immunological consequences of the original infection (see Appendix II: Immune Response).

An important conclusion of Toro Wayar is that electrocardiographic abnormalities were found in lower percentages than was commonly thought. He attributed this to strains of T. cruzi infecting the colons of patients rather than their hearts. Wayar’s conclusion supports the adaptive ability of T. cruzi strains to select intracellular locations that promote their reproductive process. As in La Paz, heart disease is especially lethal in Sucre because of hypoxia, and it is only natural that strains of parasites that reside in the colon have a longer time to reproduce than those in the heart, which die off with their hosts.

Apparently this reasoning runs counter to the findings of Jáuregui and Casanovas (1987:30‑33), who reported a higher incidence of heart disease in mesothermic regions than was typically found in tropic zones. It does suggest that many chronic chagasic patients with heart problems in La Paz were infected at lower altitudes and later moved to La Paz. The resulting hypoxic stress then interacted with chagasic heart disease to produce ECG abnormalities.

As already mentioned, natives of higher altitudes have developed physiologically to hypoxia and have well‑adapted cardiovascular systems to deal with the resulting low‑oxygen stress. Conversely, peasants migrating from the lowlands to higher altitudes lack these adaptive features and, if they become infected with Chagas’ disease, they are at greater risk for heart problems because they are unaccustomed to hypoxic stress, which interacts synergistically with chronic myocarditis. One advantage these migrant lowlanders have in living in La Paz is the decreased possibility of reinfection with additional parasites or new strains brought about by vinchuca bites. Thus, verticality, or people living at different altitudes in Bolivia, adds additional complexity to chronic Chagas’ disease in this country.

Although cardiopathy is frequently associated with chronic Chagas’ disease in Bolivia, this disease also manifests itself in other organs of the body, possibly as a function of strain diversity within T. cruzi the organisms adapting to host physiology and hypoxic stress. As living organisms, T. cruzi and humans establish parasitic relationships that dynamically vary with environmental stresses. By the time the patient is chronically ill, these parasites have become established in human organs, where they have had ample time to reproduce. It is often environmental stresses, such as moving to higher altitudes, or compromised immune systems that eventually destroy the host.

Chronic heart disease is treated symptomatically, with emphasis placed on the cardiovascular aspects. Bolivian doctors also recommend benznidazole or nifurtimox to prevent the spread of parasites from tissue to tissue, but these trypanocides are questionable with regard to their effectiveness against intracellular parasites in the amastigote form (Gutteridge 1982, 1985; Brener 1975, 1979; see also Appendix 13: Chemotherapy).