ANIMAL health remains under constant threat from exotic and emerging diseases. In Northern Europe, the emergence of Schmallenberg virus (SBV) in 2011 provided a particularly dramatic example of this (Beer and others 2013), but there are many other diseases to consider. A paper by Raith and colleagues, summarised on p 124 of this issue of Veterinary Record describes how some impacts of a porcine disease that emerged in the 1990s could be mitigated. Evidence of porcine multisystemic wasting syndrome (PMWS), a wasting disease of pigs, first emerged in Canada in the 1990s (Allan and Ellis 2000). It was found to be associated with infection with porcine circovirus type 2 (PCV-2). Retrospective testing of stored tissues showed that PCV-2 had been present in pigs in many countries before the emergence of PMWS; for example, it was shown to be present in archived material from the 1970s in the UK (Grierson and others 2004). PMWS was identified in the UK in 1998 (Done and others 2001) and it is interesting to speculate whether current changes in animal health surveillance would have altered our ability to detect it. As with SBV, the high incidence and dramatic impact of infection on morbidity and mortality on many …