PCV2 viremia in newborn piglets on endemically infected sow farms is extremely rare

Background & objectivesWhereas PCV2 associated disease (PCVAD) occurs mostly in pigs of >10 weeks of age, the time of infection is usually earlier. The number of piglets borninfected influences infection dynamics greatly and consequently the suitability of control strategies [1]. US based studies indicate a high PCV2 prevalenceat birth [2,3,4], but studies under EU conditions are scarce [5]. Objective of this study: to estimate PCV2 prevalence innewborn pigs on endemicallyinfected farms.Material & MethodsAssuming a beta binomial distribution of PCV2, sample size calculation resulted in sampling 8 piglets from 11 litters to obtain an prevalence estimateof 0.3±0.1 per farm, with a between litter variation of rho=0.5. The study was repeated in four farms, to improve external validity. Farms met theseinclusion criteria: breeding own replacement stock, no PCV2 sow vaccination, dynamic sow group housing, no clinical PCVAD. From piglets, EDTA bloodsamples were obtained from the umbilical cord directly at birth. From sows, serum samples were obtained after farrowing. All piglet and sow samples wereanalysed by qPCR for PCV2 DNA and serum samples were analysed for IgM and IgG antibodies by ELISA.Results0/352 piglets and 0/44 sows tested positive for PCV2 DNA. None of the sows tested positive for IgM. In farm A, none of the sows tested IgG positive,whereas in farms B, C and D, 13/33 sows tested PCV2 IgG positive.Discussion & ConclusionThe prevalence of PCV2 in newborn piglets in the sampled herds is much lower than can be expected from literature [2,3,4]. The findings warrant strictimplementation of hygienic measures to prevent infection of PCV2 free litters.References1. Andraud et al., Prev. Vet. Med. 2009.2. Dvorak et al., Vet Microbiol. 2013.3. Fangman et al., Proc. IPVS. 2014. P038.4. Shen et al., Prev Vet Med. 2010.5. Eddicks et al., Vet Microbiol. 2016