Canine Distemper Virus Vaccine Research Articles

The serological response of the common seal ( Phoca vitulina) and the grey seal ( Halichoerus grypus) to phocine distemper virus as measured by a canine distemper virus neutralisation test

The application of a canine distemper virus (CDV) neutralisation test revealed that antibody titres of up to 11 620 were present in the sea of common seals during the epizootic of phocine distemper in British waters. However, during the later stages of the epizootic and afterwards, a surprisingly high proportion of animals were still seronegative. Titres of from 90 to 183 were common in diseased animals and were probably indicative of partial immunosuppression. A few animals with proven phocine distemper had titres of less than 64, this being evidence of a more profound immunosuppression. Recovered animals tended to have moderate to high titres and in some cases these persisted for at least 6.5 months. By contrast, the administration of an inactivated CDV vaccine produced antibody which declined rapidly to very low levels within the same period. Infection also occurred in grey seals in 1988 but without severe mortality. Antibody titres in this species nearly always lay in the range 128–734 and persisted at or around this level for at least 12 months. In both common and grey seals, antibody was transferred by suckling from mother to pup but absorption by the pup seemed to take place more slowly than in domestic mammals.

4990367 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific Company

4990367 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific Company

4992272 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific

4992272 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific

4992272 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific

4992272 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific

5000951 Multivalent canine distemper virus vaccine: Edmund P Bass, William H Kelsey assigned to Diamond Scientific Company

5000951 Multivalent canine distemper virus vaccine: Edmund P Bass, William H Kelsey assigned to Diamond Scientific Company

4990367 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific Company

4990367 Canine distemper virus vaccine: Edmund P Bass, William H Kelsey, Michael D McFarland assigned to Diamond Scientific Company

Mass mortality in seals caused by a newly discovered virus-like 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 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 north-western European seals were infected, raises new questions about the origin of this infectious disease in pinnipeds.

Vaccine‐associated Canine Distemper Infection in a Litter of African Hunting Dogs (Lycaon pictus)

Four, 57 days old, African hunting dog puppies (Lycaon pictus) from one litter died within three weeks following vaccination with modified-live canine distemper virus (CDV) and killed canine adenovirus type 1, canine parvovirus and Leptospira icterohemorrhagiae and canicola. 18 days post vaccination, the animals developed neurologic disease characterized by episodes of grand mal seizures and circling. Macroscopic, histological and immunohistochemical studies revealed acute systemic CDV infection with acute encephalopathy. Virus isolation attempts using primary dog kidney cells, lung macrophages and Vero cells were negative. Therefore, the question whether the infection was the result of vaccination or natural infection remains open. The benefits and risks regarding the use of modified-live CDV vaccines and killed canine distemper vaccines in exotic carnivores are briefly discussed.

Vaccination of harbour seals (Phoca vitulina) against phocid distemper with two different inactivated canine distemper virus (CDV) vaccines.

Two inactivated canine distemper virus (CDV) vaccines--an adjuvanted whole inactivated virus and a subunit ISCOM preparation--were tested for their ability to induce protective immunity in harbour seals (Phoca vitulina) against phocid distemper, a disease that recently killed greater than 17,000 harbour seals in the North and Baltic seas, and was shown to be caused by infection with a newly discovered morbillivirus, which is antigenically closely related to CDV. Four CDV seronegative harbour seals were vaccinated three times with the whole-virus vaccine, two with the ISCOM subunit vaccine and two were sham-vaccinated with an antigen-free preparation. Ten days after the last vaccination, when all six vaccinated animals had developed CDV neutralizing antibody titres ranging from 300 to 3000, all eight animals were challenged by the oculonasal and the peritoneal routes, with an organ suspension from dead seals. None of the six vaccinated animals developed clinical signs. The two sham-vaccinated seals died on days 14 and 18, respectively, after having shown a body temperature rise, respiratory symptoms and weight loss. In organs from both dead animals morbillivirus antigen was demonstrated with an enzyme-linked immunosorbent assay and an immunofluorescence assay. One of these two animals had developed a low titre of CDV-specific antibodies just before death. These data clearly indicate that seals can be protected from fatal challenge with the phocid distemper virus (PDV), by vaccination with certain inactivated CDV vaccines. They also reconfirm that infection with PDV should be considered the primary cause of the recent epizootic in seals.

Measles virus and inactivated canine distemper virus induce incomplete immunity to canine distemper.

Pairs of specific pathogen free dogs were immunized with two injections of heat inactivated canine distemper virus (CDV) or one injection of a live CDV or live measles virus (MV) vaccine. Three unimmunized dogs were used as controls. All 9 dogs were challenged with virulent CDV (Snyder Hill strain). The three unimmunized dogs developed severe signs of disease with a lethal infection in one. The two dogs immunized with live CDV vaccine developed a strong humoral as well as cellular immune response after immunization and were protected against virus replication. Animals immunized with either inactivated CDV or modified live MV failed to develop a measurable cellular immune response after immunization and had a comparatively weak humoral immune response to distemper antigens. They showed mild signs of infection after challenge and responded with strong anamnestic cellular and humoral immunity. The measles vaccine immunized dogs had a moderate serum titer of measles hemolysin-inhibiting antibodies which, after exposure to distemper virus, was boosted to high levels. It is proposed that this response plays a role in the mitigation of the virulent distemper infection in these animals.

Effects of chloramphenicol on the development of immune responses to canine distemper virus in beagle pups.

The effect of oral chloramphenicol (CHPC) on the development of immune responses to canine distemper virus (CDV) in Beagle pups was studied. Dogs were treated with CHPC for 14 days at a dose of 50 mg/kg, three times a day. Hematologic changes in CHPC-treated dogs included: polychromasia, anisocytosis, and target cell formation of red blood cells concurrent with vacuolation of lymphocytes and basophilic granule formation in neutrophils. Dogs given this therapy showed normal in vivo and in vitro immune responses after CDV vaccination and survived a virulent CDV challenge, whereas untreated, unvaccinated dogs became ill or died after challenge exposure. The results of this study indicate that CHPC therapy does not interfere with either the prechallenge immune response to attenuated viral antigen or the efficient immune mechanisms invoked during virulent virus challenge.