Since its discovery, Porcine circovirus type 2 has emerged as one of the most relevant swine infectious
diseases, causing relevant economic losses for the pig industry. While four genotypes were identified,
only three (PCV2a, PCV2b and PCV2d) are currently circulating and display a worldwide distribution.
Another genotype, PCV2c, has been described only once in Danish archive samples collected between
1980 and 1990. In addition to commercial pigs, PCV2 has been demonstrated to infect wild boars and
other wild species, which can potentially serve as a reservoir for domestic populations. In this study, eight
sequences obtained from feral pigs in the Pantanal region (Mato Grosso do Sul State, Brazil) were
compared with reference sequences and other Brazilian sequences, and the results revealed remarkable
genetic diversity, with all four genotypes currently recognised being detected (PCV2a, PCV2b, PCV2c and
PCV2d). This
finding represents a remarkable discovery, as it is the
first detection of PCV2c since 1990 and
the
first-ever detection of PCV2c in live animals. The peculiar population history and ecological scenario
of feral pigs in the Pantanal coupled with the complex, and still only partially known relationship of feral
pigs with other PCV2 susceptible species (i.e., domestic pigs, wild boars and peccaries), open exciting
questions concerning PCV2 origin and evolution. Overall, the results of the present study led us to form
the following hypothesis: the PCV2 strains found in feral pigs may be the last descent of the strains that
circulated among European pigs in the past, or they may have infected these feral pigs more recently
through a bridge species