Prevalence of Akabane Virus and Properties of Its Isolates in Ishikawa Prefecture

Abstract

Nine cases of congenital abnormalities were observed from December1998 to May1999 in Ishikawa Prefec-ture. One was a case of stillbirth, three were cases of arthrogryposis, and two were instances of weak consti-tution. Three cases of hydranencephaly occurred from March to May during the latter phase of this epidem-ic. Six strains of Akabane virus (AKV) were isolated from serum and blood cell samples taken from six sen-tinel cattle. Cross-neutralizing tests showed these isolates to be identically antigenic to the JaGAr39, OBE-1, and NBE-9 strains of AKV but to be antigenically more distant from the Iriki strain of AKV. Comparisons of genetic properties of23 strains of AKV as determined by phylogenetic analysis of the S RNA sequence showed the isolates to belong to the cluster including the JaGAr39, OBE-1, and NBE-9 strains and to be similar to strains isolated in1988 and1989 in Nagasaki and Okinawa Prefectures.