Chagas' Disease in Bolivia: Clinical and Epidemiological Features and Zymodeme Variability of Trypanosoma Cruzi Strains Isolated from Patients

Abstract

Abstract. We performed serological and pathological studies on 495 patients with Chagas' disease from different areas of Bolivia. Eighty-nine Trypanosoma cruzi strains, isolated by xenodiagnosis, were characterized by 12 isoenzyme loci and were related to the presence of cardiac changes and enteric disease with megacolon. There was a high heterogeneity of human zymodemes, presenting evidence of 2 predominant zymodemes genetically dissimilar from each other and ubiquitous in Bolivia. The frequencies of these predominant zymodemes among strains from patients were compared to strains from triatomine bugs previously studied. We observed mixtures of different zymodemes within the same patient, a phenomenon seen previously in Bolivian patients. There was no apparent difference of pathogenicity between the 2 more frequent zymodemes isolated from humans.Trypanosoma cruzi, the agent of Chagas' disease, is associated with 2 main clinical forms, cardiac and intestinal. These clinical forms are not equally distributed within the geographical range of the disease, and it has been proposed that T. cruzi zymodeme distribution could explain this fact.' We present here pathological, serological, and parasitological studies, involving 495 patients from Bolivia, showing the diversity of the clinical forms and the distributions of these clinical forms and T. cruzi zymodemes isolated from human. The relationships are presented and discussed. MATERIALS AND METHODS PatientsTwo groups were examined at different times and under different conditions. Group I, consisting of 364 patients, was from the villages of Chiwisivi (Department La Paz) at 2,800 meters above sea level (mas), Salinas (Department Santa-Cruz) at 800 mas, and Camiri (Department Santa-Cruz) at 800 mas ( Table 1) The second group was composed of 13 1 patients, all exhibiting a positive serology (serodiagnosis as noted above). They originated from different endemic regions of Bolivia, although 108 had been living in La Paz (3,600 mas) for at least 5 years (average time spent in La Paz: 10 years). The endemic areas where the patients had spent their childhoods or the first endemic area where they had spent > 1 year were considered the geographical origins of infection ( Table 2). The following tests were conducted ECG, x-ray of the right anterior side of the esophagus, and x-ray of colon after barium washing (4 x-ray fìlms. Group II patients were then classified as follows:Asymptomatic-positive serology, normal ECG, normal esophagus and colon.Cardiopathy-positive serology, ECG with 52 1

Selection of Trypanosoma cruzi clonal genotypes (clonet 20 and 39) isolated from Bolivian triatomines following subculture in liquid medium

“…Natural mixtures of T. cruzi clones were previously evidenced by observation of mixed isoenzyme profiles and by isolation of different zymodemes from a single host (Tibayrenc et al 1986, Brenière et al 1989). More recently, the direct identification of T. cruzi in fecal samples by clonet specific DNA probes, showed that population mixtures in Bolivian T. infestans vectors are more frequent (Bosseno et al 1996) than those detected by isoenzyme typing (10%).…”

“…Parasite stocks are isolated directly from the digestive tract of insect vectors, and from blood of infected mammals and patients by haemoculture, xenodiagnosis and inoculation of blood into mice. The in vitro culture step is always necessary and during this amplification, a selection of clones may occur (Miles & Cibulskis 1986, Brenière et al 1989. The direct identification of T. cruzi clones or groups of clones genetically related (clonet), in feces and blood, provided a tremendous contribution to confirm the heterogeneity within an infecting population (Avila et al 1991, Veas et al 1991.…”

Integrate Study of a Bolivian Population Infected by Trypanosoma cruzi, the Agent of Chagas Disease

“…The rural population has been considered as the main population at risk of infection, however, it was recently shown that vectorial transmission is occurring in suburbs of the main cities too (Revollo et al 1997, Albarracin-Veizaga et al 1999. Moreover, cardiac morbidity as well as digestive alterations remain important (Weinke et al 1988, Brenière et al 1989, Pless et al 1992.…”

Assessment of Rectocolonic Morphology and Function in Patients with Chagas Disease in Barcelona (Spain)

“…Prevalence of gastrointestinal involvement in Chagas disease patients varies depending on the tests performed for the evaluation and the geographical area where the study is performed: gastrointestinal involvement prevalence in endemic countries ranges from 14% to 35%, although in non-endemic countries it is 5-14%. [3][4][5][6][7][8][9] Patients with chronic Chagas disease and colonic involvement show slowly progressive constipation and may manifest colonic dilatation or megacolon that can be discovered as a result of radiological examinations. The sigmoid and the rectum are dilated in nearly all cases of megacolon, whereas dilation of more proximal colonic segments is rare.…”