| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1999: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Research Abstract |
The clinical patterns of Chagas' disease show geographical variations ; in South America both the digestive and cardiac disorders are seen, while in Central Ameyica only the cardiopathy form is known. One of the possible causes of this difference seems to be genetic difference in T.cruzi. It is necessary to examine the phylogenetic features of T.cruzi in Latin America, and compare them with the geographic variation of the disease. There have been very few comparative studies of genetic structure of T.cruzi between Central and South America. Authors previously reported that no unique strains to South America have been observed in Central America by isozyme analyses with 57 Guatemalan isolates and 11 South American ones (Higo et al., 1997). In the present study, we obtained 24 isolates of T.cruzi mainly from humans in South America, and analyzed isozyme patterns of these isolates. Zymograms were also analyzed genetically for assessing the degree of genetic exchange.
As a result, 25 zymodemes were detected in the genotype examination of totally 123 isolates, and they were classified into 3 main lines : Group 1, 2, and 3. They showed a clear geographic variation, that is, Group 1 was located in Central America and Northern part of South America, Group 3 was in Central and Southern part of South America. The distribution of Group 3 is very similar to that of the intestinal disorder in the clinical manifestation, consequently there seems to be some relation between the clinical manifestations and the lineage of T.cruzi. In the genetic analyses of the zymograms, Genetic exchanges in South American populations were suggested by the findings of hybrid patterns between different Groups.
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