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

Abstract

Neutralizing antibodies to San Miguel sea lion virus (SMSV) types 6 and/or 7 were found in sera collected from California sea lions Zalophus c. californianus in 1977 and 1983, and in sera collected from Steller sea lions Eumetopias jubatus in 1976 and 1985. The combined prevalence rates of SMSV antibodies in these 2 species were: SMSV-6, 19/228 = 8.3%, and SMSV-7, 4/228 = 1.7%. Seropositive sea lions were dispersed along the eastern Pacific rim from Alaska to the southern California Channel Islands. Antibodies to either agent were not found in sera collected from northern fur seals Callorhinus ursinus , Pacific walruses Odobenus rosmarus divergens , seals of the family Phocidae, or several cetacean species. The presence of antibody-positive sea lions in more northern waters indicates that these piscine-origin SMSV types may have a wider distribution in nature than has been previously supposed.