Enfermedad de Chagas en el Altiplano Chileno: aspectos epidemiológicos, parasitológicos y clínicos / Chagas disease in Chilean altiplane: epidemiological, parasitological, and clinical aspects

ABSTRACT

Chagas'disease is endemo-enzootic in periurban and rural sections of the first seven (18-30'-34-36' South lat), out of the thirteen political-administrative regions of Chile. Permanent inhabited localities situated at different altitudes over the sea level (OSL) are clasified in: coastal settlement (0-1,499 , OSL), intermediate settlement (1,500-3,000 m OSL) and altiplano settlement (>3,000 m OSL). A total of 1,558 dwellings and their occupants from regions I and II were surveyed in 1982-1984 for different epidemiological Trypanosoma cruzi infection parameters. Hence, 261 dwellings, 189 domestic mammals and 517 people (ages 5-*60 years) from the Altiplano settlement were studied. The results obtained were: 4(1.5% ) and 1(0.8% ) of dwellings infested with Triatoma infestans, according to occupants information and by observation of direct evidences respectively; 8(4.2% ) animals (1 dog, 4 goats and 3 sheep) with a positive hemagglutination test (IHAT) for Chagas' disease; 21 people (4,1% ) with a positive IHAT; 4(19.0% ) and 3(14.3% ), out of the 21 IHAT positive individuals with all types of electrocardiogram (EKG) abnormalities and EKG abnormalities suggestive of a chagasic etiology respectively, whereas 65(13.1% ) and 15(3.0% ), out of the 496 IHAT negative ones presented the same kinds of EKG abnormalities. In comparing the frequence of presumedly chagasic EKG abnormalities in 91, 258 and 21 IHAT positive individuals from the three settlements surveyed, eventhough the figures lack of statistical significance, it is interesting to emphasize the increasing of percentages, paralell to altitutde, observed from 4.4 in the coastal settlement to 6.2 in the intermediate settlement up to 14,3 in the Altiplano, suggesting a possible influence of this factor in the production of EKG abnormalities. A similar situation was observed in 1,155, 1,211 and 496 IHAT negative individuals with the corresponding percentages of 2.1, 1.8 and 3.0