title: [The PRRSV-serumneutralization test detects gaps in herd immunity].
abstract: Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) appears in two genotypes (EU and US), for both genotypes attenuated live-vaccines are available. A cross-sectional study in 38 Bavarian sow herds was performed to assess the level of neutralizing antibodies. Per herd 38 blood samples were collected (10 weaned piglets, 10 gilts and 6 sows of 1./2., 3J4. and 5/6. parity, respectively). Sera were tested by ELISA, serumneutralization test (SNT) against EU- and US-vaccine virus, and pooled sera were tested by real-time RT-PCR. Herds were classified by the last vaccination of sows as "Vacc EU" "Vacc US"and "nv (non-vaccinated) and by detection of PRRSV-US and vaccination of piglets were not included as variables. Sows of group (2) Vacc EU/EU- showed the highest EU-SNT-titers irrespective of parity. Groups (5) Vacc US/EU+ and (1) Vacc EU/EU+ followed in descending order. Significantly lower SNT-titers in (1) Vacc EU/EU+ were especially observed in sows of 1/2. Parity (Kruskal-Wallis, p < 0.05). Very low SNT-titers were observed in the three remaining groups (3) nv/EU+, (4) nv/EU- and (6) Vacc US/EU-. In US-vaccinated herds detection of PRRSV-EU coincided with strong ELISA-reactivity in all animal groups. In EU-vaccinated herds this was only observed for weaned piglets. Sows showed a strong ELISA-reactivity irrespective of detection of PRRSV-EU. The value of the ELISA is restricted to the certification of PRRSV-free herds. The EU-SNT reflects the level of herd immunity at least against vaccine virus; it indicates gaps in herd immunity.
authors: Jens
authors: J
authors: Böttcher
authors: Michaela
authors: M
authors: Alex
authors: Britta
authors: B
authors: Janowetz
authors: Silvia
authors: S
authors: Müller
authors: Christina
authors: C
authors: Schuh
authors: Hermann
authors: H
authors: Niemeyer
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005062:European Union; D005260:Female; D005838:Genotype; D005858:Germany; D032521:Immunity, Herd; D008297:Male; D009500:Neutralization Tests / Q000662:veterinary*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000517:prevention & control; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D013552:Swine; D014613:Vaccines, Attenuated / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines