[Outbreak of equine influenza caused by a new strain of equine Myxovirus subtype 2. I. Etiology].

During an outbreak of acute respiratory disease in Algeria, a strain of equine influenza virus was isolated. This strain, A/Equine/Algiers/72, bears an important antigenic drift from the prototype strain A/Equine/Miami/1/63, but is closely related to a strain isolated in 1971 in Japan (A/Equine/Sachiyama/1971).