Transboundary spread of pig diseases: the role of international trade and travel

Beltran-Alcrudo, Daniel; Falco, John R.; Raizman, Eran; Dietze, Klaas

Catering and other food leftovers from airplanes and ships have often been implicated in outbreaks of exotic pathogens. While the entry itself through international carriers may in fact be legal, the infraction takes place when such food leftovers get sold for swill feeding or improperly disposed against the airport or port waste management regulations (i.e. legal entryillegal disposal; Table 1 ). African swine fever spread has provided many of such examples. It is almost certain that the long-distance spread of ASF from Angola to Portugal in 1957 took place as a result of uncooked waste food being fed to pigs near Lisbon airport [122] . Subsequent outbreaks in Cuba, Malta, Italy, Brazil and the Dominican Republic in the 70s were also attributed to feeding pigs on swill from ports or airports [3, 122] . The 1978 ASF outbreak in Brazil was linked to Spain or Portugal through a police officer at the international airport in Rio de Janeiro, who apparently collected leftovers from meals served on international flights and fed his animals [63, 71] . The 1968 ASF outbreak in the Italian island of Sardinia was probably caused through the introduction of contaminated waste from the port of Cagliari or the military airport used to feed pigs [73] . A more recent example took place in Georgia in 2007, when ASF entered through the Port of Poti in contaminated catering waste from an international cargo ship originating in Southeast Africa [12, 101] . Following this introduction, ASF has spread since throughout Eastern and Central Europe. Also in 2007, ASF most probably entered Mauritius through the harbour in the form of infected meat that ended up as illegal swill fed to pigs in one or more parts of the island [62] .