HEAL ▶▶▶TH Brazil, 1978-1981: Targeted eradication
Arguably the best documented case is what happened in Brazil in 1978 and 1979. On Floresta farm near Paracambi, about an hour’s drive from Rio de Janeiro, pigs started dying from mid-April 1978. At first, the own- er did not think much of it and business carried on as normal, which meant that infected animals continued to be sold. A review by J.A. Mou- ra (2010) describes how a South African veterinarian, while visiting the farm, suggested it might be ASF and had samples sent to a lab. Once confirmed, an investigation of where the animals had been sold was begun. It was shown that the virus had spread to 224 locations in 18 states of Brazil – a country which had roughly 34 million pigs at that time. This was mostly on other farms but some animals had also ended up in poorer areas of the city of Rio de Janeiro. Five states reported over 20 places to be positive for ASF, including the pig states Paraná and Santa Catarina, but also São Paulo, Rio de Janeiro and Pará, in the north of the country. An emergency plan was put in place, as described by ASF expert Dr Tânia Maria de Paula Lyra in various articles. A stringent approach led to the culling of almost 67,000 pigs at a cost of US$ 1.8 million. Unlike in Haiti or the Dominican Republic, however, the Brazilian authorities opted for a targeted rather than a total approach. Moura reported that also in 1981 a few posi- tive samples returned from the lab, bringing her total count to 231. It was, however, the last to be heard of ASF in Brazil, as the government’s approach proved successful. On 9 September 1983, the country was officially declared ASF-free. Worth noting is that ASF in Brazil showed a variation in virulence. In some places, the virus appeared to lead to 100% mortality, whereas in other places, lower
mortality was observed. In this context it is good to point out that the Brazil vi- rus was of genotype I, un- like the current outbreaks in Asia and Europe (geno- type II). ASF expert Dr Mary Louise Penrith, locat- ed in South Africa, com- mented to Pig Progress, “There is a lot of speculation as to whether the variation in virulence observed in Brazil might have been due largely if not entirely to pig factors. Many of the pigs were in very poor condition and this can affect expression of the virus. “Secondly, before and during the outbreaks in Brazil pigs were vacci- nated with a CSF vaccine, and it was speculated that although that would provide no specific protection against ASFv it may have boosted a non-specific immune response that altered the response of the pig to the infection.”
Last but not least – where did the ASF outbreak come from? The owner of Floresta farm was also working at the nearby Rio de Janeiro airport, which had just opened a new terminal. Dr de Paula Lyra ex- plained that, at the time, this terminal did not have an in- cinerator for leftover food brought from Europe. The owner simply brought home left- overs from planes from Portu- gal and Spain (where geno- type I was present at the time) and mixed these with the pig feed rations. The scraps were found on his farm, complete with cutlery indicating their airline origin.
Culled pigs in a mass grave at a farm in Mato Grosso, June 1978.
Feed scraps from planes found at the farm in Paracambi, RJ, Brazil, in April 1978.
8 ▶PIG PROGRESS | Volume 36, No. 1, 2020
PHOTO: DR TÂNIA MARIA DE PAULA LYRA
PHOTO: DR TÂNIA MARIA DE PAULA LYRA
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