Mass mortality in seals caused by a newly discovered morbillivirus.

During a recent disease outbreak among harbour seals (Phoca vitulina) in the North and Baltic seas, more than 17,000 animals have died. The clinical symptoms and pathological findings were similar to those of distemper in dogs. Based on a seroepizootiological study, using a canine distemper virus (CDV) neutralization assay, it was shown that CDV or a closely related morbillivirus (phocid distemper virus-PDV) was the primary cause of the disease. The virus was isolated in cell culture from the organs of dead seals and characterized as a morbillivirus by serology (immunofluorescence neutralization and enzyme-linked immunosorbent assays) and by negative contrast electron microscopy. Experimental infection of SPF dogs resulted in the development of mild clinical signs of distemper and CDV-neutralizing antibodies. The disease was reproduced in seals by experimental inoculation of organ material from animals that had died during the outbreak. However, seals that had been vaccinated with experimental inactivated CDV vaccines were protected against this challenge. This fulfilled the last of Koch's postulates, confirming that the morbillivirus isolated from the seal organs, was the primary cause of the disease outbreak. The recent demonstration of the presence of a similar virus in Lake Baikal seals (Phoca sibirica), which infected these Siberian seals 1 year before the northwestern European seals were infected, raises new questions about the origin of this infectious disease in pinnipeds

Een uitbraak van 'hondeziekte' bij zeehonden (1).

The cause of a recent outbreak of a serious disease of seals in the North and Baltic Seas, in which so far, over 9000 of the population of 16,000 animals have died, was investigated. Three viruses have been considered as the possible causative agents: a herpesvirus, a picornavirus and canine distemper virus. It was concluded mainly on the basis of serological data that canine distemper virus was the primary cause of the outbreak. The role of other factors on the extent and the severity of the outbreak needs to be investigated

Comparison of an enzyme-linked immunosorbent assay, an immunofluorescence assay and a hemagglutination inhibition assay for detection of antibodies to K-papovavirus in mice.

The sensitivity of a newly developed enzyme-linked immunosorbent assay (ELISA) for detection of antibody to K virus was compared with the sensitivities of an immunofluorescence assay (IFA) and a hemagglutination inhibition assay (HIA). Specific pathogen-free BALB/c RIVM mice, 5 weeks old, were inoculated intraperitoneally with a mouse organ suspension containing 10(4.5) TCID50 of K virus per dose. Control animals were inoculated with a control mouse organ suspension. No clinical signs were observed during the 7 weeks they were followed for the development of serum antibody. The ELISA proved to be the most sensitive of the three assays and demonstrated K virus-specific antibodies as early as 3 days after infection

Een uitbraak van 'hondeziekte' bij zeehonden (2).

Serological findings which had showed that the primary cause of the recent outbreak of serious disease of seals in the seas of North-Western Europe, is infection with canine distemper virus, were confirmed by in vivo and in vitro isolation of the virus from seals which had died at different locations during the outbreak. The virus which proved to be pathogenic for dogs, was characterised as canine distemper virus on the basis of immunofluorescence, virus neutralisation and electron microscopical studies

Purification process monitoring in monoclonal antibody preparation: contamination with viruses, DNA and peptide growth factors.

Administration in vivo of monoclonal antibodies to humans is challenged by considerations regarding their safety. Contamination with viruses, potentially oncogenic nucleic acids and biologically active components like growth factors and hormones forms a serious point of concern in this respect. We have investigated the potential risk of viral contamination by measuring the reduction of 12 different viruses (after spiking) in the standard downstream purification process of ascitic fluid. Depending on the type of virus added and the purification step employed, the reduction of infectious virus particles varies considerably. The overall reduction ranges from about 10(3), observed for a member of the family of Papovav