[Environmental impact of ecological changes in a subtropical area]

Infectious, clinical-surgical and environmental variables were studied in Ituzaingó and Posadas (Argentina) and differences were analyzed from 1994 to 2000, which corresponds to the building of the binational dam Yacyretá (Argentina-Paraguay) and to the resulting reservoir. The chosen infectious variables were diarrhea and respiratory infections and the clinical-surgical variables were cardiovascular diseases and polytraumas. Environmental variables were also investigated. Taking as a baseline the values corresponding to the year 1994, diarrhea in Ituzaingó, increased 6.5% during 1995 and 78.3% in 1996 returned to 1994 values. Posadas showed a rising tendency throughout the period investigated. In Ituzaingó, respiratory infectious rose 143% in 1995, and later returned to 1994 values. In Posadas they increased each year. Cardiovascular diseases reached 97.6% in Ituzaingó during 1995; lowered slightly in 1996 and reached 127% in the year 2000. The impact of the environmental variables was higher in Ituzaingó than Posadas. The negative impact of temperature related with the increased frequency of disease in Ituzaingó is more related to maximum temperature than with changes in humidity.