Epidemiología de la rabia en Chile (1929-1988) y perspectivas en mamíferos silvestres.
In this article we present an analysis of the evolution of rabies in Chile for the sixty year period from 1929 to 1988. Data was obtained from samples that were registered with the Rabies Laboratory of the Institute of Public Health. The analysis includes species, date, geographic location, seasonal occurrence of the desease and the diagnosis made at the time. We have reviewed the importance of monitoring the disease and its wild reservoirs.
Between 1929 and 1969 the disease was diagnosed using the direct technique of Negri corpuscle and confirmation by isolating the virus in adult mice. The accuracy of the first technique was 35% in comparison with the second. As a result there was a greater need for preventive measures vaccinations. Since 1970 the disease has been diagnosed by direct immunofluorescence, increasing the accuracy to nearly 100% in relation to the biological diagnosis in suckling mice.
Of a total of 41,191 cases, 93.61% were domestic animals, 5.99% were wild animals, and 0.4% were humans. There were 7,017 positive cases (17.04%): 97.78% domestic animals, 0.89% wild animals and 1.33% humans. Wild species account for 5.99% of the total sample and 0.89% of the positive cases. Most of the wild cases were insectivorous bats (Tadarida brasiliensis) and fox (Pseudalopex griseus, formerly Dusicyon). Of the total sample reviewed in this study 93.89% of the samples are from 6 of the 13 administrative regions in the country, and 89.04% of the positive cases occurred in four regions: the Metropolitan, V, VI, and VII. In a seasonal review, there is a lower number of positive cases during the summer.
A complementary analysis of 8,057 cases was done by five year periods. Between 1944 and 1963, the quinquennial periods had between 1,351 and 1,960 cases, with epidemic and epizootic cycles generally related to four of f ve species.
A control program was begun in 1951 that resulted in a drastic reduction in the number of cases since 1963. Only 54 cases were confirmed between 1974 and 1983. In 1982 and 1984 no cases were confirmed. In 1982 mass vaccinations were terminated, with the exception of Region I.
In 1985 these studies were broadened to include wild reservoirs and for the first time rabies was diagnosed in insectivorous bats in central Chile. A sample of gray fox was done on the continent and Tierra del Fuego in Region 12. Historically this area was free of rabies. The disease was diagnosed in 8.62 % of the animals. Rabies previously had not been identified this far south (53° 35' south) either in Chile or in South America.
Key words: epidemiology, rabies, wild mammals, Chile.
Palabras claves: epidemiología, rabia, mamíferos silvestres, Chile.