title: A turkey rhinotracheitis outbreak caused by the environmental spread of a vaccine-derived avian metapneumovirus.
abstract: Avian metapneumovirus (aMPV) subtype A was isolated from 7-week-old turkeys showing respiratory disease typical of turkey rhinotracheitis. Comparison of the virus sequence with previously determined vaccine marker sequences showed that the virulent virus had originated from a licensed live subtype A aMPV vaccine. The vaccine had neither been in use on the farm within a period of at least 6 months nor had it been used on farms within a distance of approximately 5 km. Isolation of the virus and exposure to naive turkeys caused disease typical of a virulent aMPV field strain. The study shows that disease was caused by exposure to aMPV vaccine-derived virus that was present in the environment, and indicates that such virus is able to circulate for longer than was previously envisaged.
authors.affiliation: Dipartimento di Scienze Mediche Veterinarie, Alma Mater Studiorum - University of Bologna, Via Tolara di Sopra 50,40064 Ozzano Emilia (BO), Italy. caterina.lupini@unibo.it
authors.forename: Caterina
authors.initials: C
authors.lastname: Lupini
authors.forename: Mattia
authors.initials: M
authors.lastname: Cecchinato
authors.forename: Enrico
authors.initials: E
authors.lastname: Ricchizzi
authors.forename: Clive J
authors.initials: CJ
authors.lastname: Naylor
authors.forename: Elena
authors.initials: E
authors.lastname: Catelli
mesh_terms: D000818:Animals; D001483:Base Sequence; D001715:Bird Diseases / Q000453:epidemiology* / Q000821:virology*; D016000:Cluster Analysis; D004196:Disease Outbreaks / Q000662:veterinary*; D007558:Italy / Q000453:epidemiology; D029121:Metapneumovirus / Q000235:genetics* / Q000472:pathogenicity; D008957:Models, Genetic; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012220:Rhinitis / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D017422:Sequence Analysis, DNA; D014136:Tracheitis / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D014422:Turkeys; D014765:Viral Vaccines / Q000009:adverse effects / Q000235:genetics*; D014774:Virulence
chemical_list: D014765:Viral Vaccines