- 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. Martella, V., Elia, G., Decaro, N., Di Trani, L., Lorusso, E., Campolo, M., Desario, C., Parisi, A., Cavaliere, N., Buonavoglia, C. Vet. Microbiol. (2007)