Prevalence and distribution of serum neutralizing antibodies to San Miguel sea lion virus types 6 and 7 in selected populations of marine mammals

Neutral17ing antibodies to San M ~g u e l sea llon virus (SMSV) types 6 and/or 7 were found in sera collected from California sea l ~o n s Zalophus c californianus in 1977 and 1983 and in sera collected from Steller sea lions Eumetoplas jubatus in 1976 and 1985 The combined prevalence rates of ShlSV anubodies in these 2 species were SMSV-6 19/228 = 8.3 %, and SMSV-7, 4/228 = 1 7 '10 Titers ranged from 1 20 to 1 320 by standard microtlter neutralization assay Seropositive sea lions were dispersed along the eastern Pacific rim from Alaska to the southern California Channel Islands Anhbodies to either agent were not found In sera collected from northern fur seals Callorhlnus urslnus, Pacific walruses Odobenus rosnlarus divergens seals of the family Phocidae, or several cetacean species Both SMSV-6 and SMSV-7 have been isolated from opaleye G~rella nlgrIcans an ocean fish found pnmarily In the southern California coastal zone, the presence of antibody-positive sea llons in more northern waters indicates that these piscine-ongin SMSV types may have a wider distribution in nature than has been previously supposed