An outbreak of equine influenza virus in vaccinated horses in Italy is due to an H3N8 strain closely related to recent North American representatives of the Florida sub-lineage.
In December 2005, equine influenza virus infection was confirmed as the cause of clinical respiratory disease in vaccinated horses in Apulia, Italy. The infected horses had been vaccinated with a vaccine that contained strains representatives from both the European (A/eq/Suffolk/89) and American (A/eq/Newmarket/1/93) H3N8 influenza virus lineages, and the H7N7 strain A/eq/Praga/56. Genetic characterization of the hemagglutinin (HA) and neuraminidase (NA) genes of the virus from the outbreak, indicated that the isolate (A/eq/Bari/2005) was an H3N8 strain closely related to recent representatives (Kentucky/5/02-like) of the American sub-lineage Florida, that was introduced in Italy through movement of infected horses from a large outbreak described in 2003 in United Kingdom. Strain A/eq/Bari/2005 displayed 9 amino acid changes in the HA1 subunit protein with respect to the reference American strain A/eq/Newmarket/1/93 contained in the vaccine. Four changes were localized in the antigenic regions C-D and likely accounted for the vaccine failure.
Martella
Vito
V
Department of Animal Health and Well-being, University of Bari, Valenzano, Bari, Italy. v.martella@veterinaria.uniba.it
Elia
Gabriella
G
Decaro
Nicola
N
Di Trani
Livia
L
Lorusso
Eleonora
E
Campolo
Marco
M
Desario
Costantina
C
Parisi
Antonio
A
Cavaliere
Nicola
N
Buonavoglia
Canio
C
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks / Q000662:veterinary*; D006388:Hemagglutinins / Q000737:chemistry / Q000235:genetics; D006734:Horse Diseases / Q000453:epidemiology* / Q000821:virology*; D006736:Horses; D053123:Influenza A Virus, H3N8 Subtype / Q000235:genetics / Q000254:growth & development*; D007558:Italy / Q000453:epidemiology; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000737:chemistry / Q000235:genetics; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012140:Respiratory Tract Diseases / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D016415:Sequence Alignment; D014611:Vaccination / Q000662:veterinary
D004279:DNA, Viral; D006388:Hemagglutinins; D009439:Neuraminidase