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Year 2004 - Volume 24, Number 4
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O surto de peste suína africana ocorrido em 1978 no município de Paracambi, Rio de Janeiro
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Tokarnia C.H., Peixoto P.V., Döbereiner J., Barros S.S. & Riet-Correa F. 2004. [The outbreak of African swine fever which ocurred in 1978 in the county of Paracambi, Rio de Janeiro, Brazil.] O surto de peste suína africana ocorrido em 1978 no município de Paracambi, Rio de Janeiro. Pesquisa Veterinária Brasileira 24(4):223-238. Projeto Sanidade Animal Embrapa/UFRRJ, Km 47, Seropédica, RJ 23890-000, Brazil. E-mail: tokarnia@ufrrj.br
Due to doubts which still persist 25 years after the outbreak of African swine fever (ASF) which ocurred in the county of Paracambi, Rio de Janeiro, Brazil, in 1978, the results obtained through the studies to establish and confirm the diagnosis are presented. These include data on the epidemiology, clinic-pathological aspects, bacteriological, virological and ultramicroscopic examinations, the experimental reproduction of the disease and cross immunity tests with classical swine fever virus performed in Brazil, and on the confirmation with isolation of the virus and determination of its identity at the Plum Island Animal Disease Center, New York, USA. The pigs of the affected herd had been fed untreated remains of meals from airplanes of international lines flying to Brazil from Portugal and Spain where ASF was occurring at the time. According to publication by the Ministry of Agriculture, after the diagnosis of the outbreak of ASF described in this paper, 223 additional outbreaks were reported in Brazil between 1978 and 1979, in all the Brazilian regions (North, Northeast, Central-West, Southeast and South). Further outbreaks were reported in 1981, but their number is not known. The last case was reported to have occurred on November 15, 1981, and on December 5, 1984, Brazil was declared free of ASF. For the diagnosis of ASF 54,002 samples were examined by the Department of Virology of the Institute of Microbiology, Federal University of Rio de Janeiro, from 1978 to 1981, by the techniques of haemadsorption in leucocyte cultures (HAd), direct immunoflorescence in tissue sections (FATS), direct immunoflorescence in cell cultures (FATCC), immuno-electro-osmophoresis (IEOP) and indirect immunoflorescence assay (IIF). Only 4 samples were positive with the FATCC procedure. This is the only technique which includes virus isolation; the origin of these positive samples was not reported, but probably they were from the Paracambi outbreak.
From other suspected outbreaks of ASF in Brazil there is no information on the isolation and characterization of the virus isolates. Likewise there is no information available about the epidemiology, clinical signs, and pathology of suspected ASF in other outbreaks. The analysis of all published data on this matter in Brazil, the possibility of false-positive results, the lack of information about isolation and characterization of the virus, as well as the lack of epidemiological, clinical and pathological data of these other supposed outbreaks of ASF strongly suggest that the outbreak of Paracambi was the only occurrence of ASF in Brazil, confirmed by the isolation, identification of the virus, and the determination of its pathogenicity, and that ASF occurred and maintained itself confined to this area probably due to the early diagnosis and the rapid application of efficient control measures by the Brazilian authorities; the slaughter of the animals in the outbreak of Paracambi started as soon as 10 days after the first death, 3 days after the presumptive diagnosis. |
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