A molecular survey on Avian Metapneumovirus (aMPV) diffusion was performed from 2011 to 2013 in 122 turkey and 48 broiler farms, located in a densely populated poultry area of Northern Italy. Turkeys were all vaccinated at 1 day of age in the hatchery. aMPV was detected using RTnested PCR or qRT-PCR; both tests are able to detect and differentiate aMPV subtypes A and B. All samples but one resulted positive for aMPV subtype B confirming the high prevalence of this subtype in Italy. The majority of aMPV detections were of field origin, circulating mainly in 9 to 12- week-old turkeys and 5 to 7 week-old broilers, showing respiratory signs. The reasons for vaccine failure could be due to field virus changes occurred in key antigenic regions, which allow virus replication and disease in well-vaccinated birds. Strains of vaccine origin were detected in turkeys with a high prevalence during the first few weeks after vaccination with aMPV live vaccines. This confirmed the pattern previously seen where vaccine viruses were shown to persist on farm for 4-5 weeks. Uniquely in this study, vaccine derived strains were detected in older turkeys of up to 84 days of age. Moreover, sequence analysis of F and G protein genes of selected strains was performed.

AN UPDATE ON THE EPIDEMIOLOGY OF AVIAN METAPNEUMOVIRUS IN ITALY

LUPINI, CATERINA;LISTORTI, VALERIA;LACONI, ANDREA;CATELLI, ELENA
2014

Abstract

A molecular survey on Avian Metapneumovirus (aMPV) diffusion was performed from 2011 to 2013 in 122 turkey and 48 broiler farms, located in a densely populated poultry area of Northern Italy. Turkeys were all vaccinated at 1 day of age in the hatchery. aMPV was detected using RTnested PCR or qRT-PCR; both tests are able to detect and differentiate aMPV subtypes A and B. All samples but one resulted positive for aMPV subtype B confirming the high prevalence of this subtype in Italy. The majority of aMPV detections were of field origin, circulating mainly in 9 to 12- week-old turkeys and 5 to 7 week-old broilers, showing respiratory signs. The reasons for vaccine failure could be due to field virus changes occurred in key antigenic regions, which allow virus replication and disease in well-vaccinated birds. Strains of vaccine origin were detected in turkeys with a high prevalence during the first few weeks after vaccination with aMPV live vaccines. This confirmed the pattern previously seen where vaccine viruses were shown to persist on farm for 4-5 weeks. Uniquely in this study, vaccine derived strains were detected in older turkeys of up to 84 days of age. Moreover, sequence analysis of F and G protein genes of selected strains was performed.
8th SYPMOSIUM on ACOV & AMPV / 2nd MEETING COST ACTION 1207, RAUISCHHOLZHAUSEN, GERMANY, JUNE 2014
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M. Cecchinato; M. Drigo; C. Lupini; M. Martini; V. Listorti; G. Franzo; A. Laconi; E. Morandini; C.J. Naylor; E. Catelli
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/524343
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