Molecular epidemiology of classical swine fever in Italy

To gain an insight into the molecular epidemiology of classical swine fever (CSF) in Italy, virus isolates originating from outbreaks that occurred be tween 1985 and 2000 in wild boar or in domestic pigs in mainland Italy and in Sardinia were analysed by genetic typing. For this, a fragment (190 nucl eotides) of the E2 glycoprotein gene was sequenced and phylogenetic analyse s were performed, including older Italian isolates and isolates from recent outbreaks in Europe for comparison. The results show that in mainland Ital y, several independent epidemiological events occurred in the last decade. In the north of the country, viruses of genotype 2.2 have persisted in wild boar, causing sporadic outbreaks in domestic pigs. In contrast, viruses of subgroups 2.1 and 2.3 appeared only intermittently in different regions of the mainland. In 1997, classical swine fever virus (CSFV) isolates belongi ng to the subgroup 2.1 and genetically and epidemiologically related to the Dutch isolate in Venhorst, affected domestic pigs exclusively. The isolate s of subgroup 2.3, derived from wild boar as well as from domestic pigs wer e closely related to isolates from Germany and Poland. In Sardinia, CSF is an endemic in wild boar and affects domestic pigs also. Genetic typing show ed that viruses of subgroups 1.1 and 2.3 have been present, the last ones b eing unrelated to the mainland viruses of the same subgroup. Due to the lar ge quantities of pig and wild boar meat imported in some parts of Italy, it cannot be established if these viruses were always present in either the m ainland or Sardinia, or if they represent recent introductions. (C) 2001 El sevier Science B.V. All rights reserved.