Distemper‐like disease in Harbor Seals: Virus Isolation, further Pathologic and Serologic Findings*

Abstract

Pathologic-histologic and immunocytologic as well as serologic findings from a total number of 50 recently dead or euthanatized moribund harbor seals (Phoca vitulina) are described. In 14 of 31 histologically examined brains of affected seals alterations corresponding to canine distemper encephalitis (CDE) were found. Immunofluorescence-serologic tests using polyclonal as well as monoclonal antibodies against canine distemper virus (CDV) resulted in positive findings in organ sections of 24 dead seals. An agent was isolated from organs of dead seals and subjected to several passages in vero cell cultures as well as in primary seal lung-cell cultures. The agent was able to be identified as canine distemper-like virus with both antibodies.CDV neutralising serum-antibodies were detected in 13 out of 19 serum specimens. Further interdisciplinary investigations are required to determine whether the virus induced alterationsstill to be interpretated only in a purely qualitative senseshould be considered as the manifestation of contributing ecological factors, or as the primary cause of the still present deaths of harbor seals.

Antarctic seals carry antibodies against seal herpesvirus

“…A new morbillivirus, the phocine distemper virus (PDV), was regarded to be responsible for the epizootic [2,[5][6][7]10]. The seal herpesvirus (SeHV) was frequently isolated by our and other groups [3,9,11,12].…”

Isolation and characterisation of a porpoise morbillivirus

“…The isolation of morbilliviruses from porpoises presents difficulties similar to those reported by other workers in the isolation of PDV [11,2,7]. It has been reported that PDV grows poorly in Vero cells and that primary dog and seal kidney cells are most sensitive [7].…”

Polioencephalomalacia in Captive Harbour Seals (Phoca vitulina)

“…Phocine and porpoise distemper virus infections caused lethal non‐suppurative encephalitis in a variety of aquatic mammals during the epidemics in north‐western Europe in 1988, along the north‐eastern coast of America in 1992 and in the Mediterranean from 1990 to 1992 (Duignan et al, 1993; De Swart et al, 1995; Kennedy, 1998). In seals, the central nervous lesions were characterized by necrosis of neurones and glial cells, perivascular cuffing, microglial infiltration and demyelination (Hofmeister et al, 1988; Kennedy et al, 1989; Duignan et al, 1993). A single case of rabies has also been reported in a ringed seal ( Pusa hispida ) (Ødegaard and Krogsrud, 1981).…”