Humoral immune responses to phocine herpesvirus-1 in Pacific harbor seals (Phoca vitulina richardsii) during an outbreak of clinical disease

Infection with phocine herpesvirus type-1 (PHV-1) has been associated with morbidity and high mortality in neonatal harbor seals (Phoca vitulina). A P HV-1 specific indirect enzyme linked immunosorbent assay (ELISA) was develo ped to sequentially measure the serological status of 106 harbor seal neona tes admitted to a Pacific coast rehabilitation center (total number of sera rested was 371), Early in the season (February-April), the majority of pup s had low serum levels of PHV-1 specific antibody. A dramatic increase in P HV-1 specific antibody, involving the majority of hospitalized pups, was ob served during a 4-week period in May. This coincided with a high incidence of PHV-1 associated adrenal lesions and mortality. Although there was overa ll agreement between the timing of seroconversion to PHV-1 and histological evidence of PHV-1 infection, 82.4% of individual pups with adrenalitis had no evidence of a humoral response to PHV-1 at the time of their death. Thi s suggests either a rapid disease course, or an inability to develop a humo ral response in some neonatal seals. (C) 2001 Elsevier Science B.V. All rig hts reserved.