Canine Distemper Virus Vaccine Research Articles

COMPARISON OF ORAL AND INTRAMUSCULAR RECOMBINANT CANINE DISTEMPER VACCINATION IN AFRICAN WILD DOGS (LYCAON PICTUS)

A series of three doses of recombinant canary-pox-vectored canine distemper virus vaccine was administered at 1-mo intervals, orally (n = 8) or intramuscularly (n = 13), to 21 previously unvaccinated juvenile African wild dogs (Lycaon pictus) at the Wildlife Conservation Society's Bronx Zoo. Titers were measured by serum neutralization at each vaccination and at intervals over a period of 3.5-21.5 mo after the initial vaccination. All postvaccination titers were negative for orally vaccinated animals at all sampling time points. Of the animals that received intramuscular vaccinations, 100% had presumed protective titers by the end of the course of vaccination, but only 50% of those sampled at 6.5 mo postvaccination had positive titers. None of the three animals sampled at 21.5 mo postvaccination had positive titers.

SEROLOGIC RESPONSE OF HARBOR SEALS (PHOCA VITULINA) TO VACCINATION WITH A RECOMBINANT CANINE DISTEMPER VACCINE

Morbilliviruses pose a significant threat to marine mammal populations around the world and have been associated with multiple epizootics in pinnipeds and cetaceans. As part of a preventive veterinary medical program, five harbor seals (Phoca vitulina) in a managed collection were vaccinated with a recombinant canarypox-vectored canine distemper virus vaccine. The vaccine was evaluated for safety (by monitoring seals for local and systemic adverse effects and by testing for shedding of the canarypox vector) and efficacy (by testing for serum neutralizing antibodies). None of the seals showed signs of local or systemic adverse reactions to the vaccination. Three seals vaccinated once did not seroconvert, but the recombinant vaccine induced a persistent serum virus neutralizing titer (12 mo) in the two seals that were vaccinated twice, 1 mo apart.

Supplementation of diets with bovine colostrum influences immune function in dogs

While the need for colostrum in neonates is well established, the systemic effect of feeding bovine colostrum (BC) to adult humans is gaining increasing attention. However, no systematic studies evaluating the immunomodulatory effect of BC in dogs have been reported. The aim of the present study was to evaluate the immunomodulatory effect of dietary supplementation of BC in dogs. The study was conducted in two phases: pre-test (8 weeks) and test (40 weeks), with twenty-four dogs (mean age 2.5 years) randomised into two groups. In the 'pre-test' phase, both groups were fed a nutritionally complete diet. At the end of the 'pre-test' phase, all dogs received a canine distemper virus (CDV) vaccine, and dogs in the 'test group' were switched to a diet supplemented with 0.1% spray-dried BC. Response to the CDV vaccine was evaluated by measuring vaccine-specific plasma IgG levels. Gut-associated lymphoid tissue response was assessed by measuring faecal IgA levels. Gut microbiota were evaluated by the temporal temperature gel electrophoresis methodology. Dogs fed the BC-supplemented diet demonstrated a significantly higher vaccine response and higher levels of faecal IgA when compared with the control group. Supplementing diets with BC also resulted in significantly increased gut microbiota diversity and stability in the test group. In conclusion, diets supplemented with BC significantly influence immune response in dogs.

Serum-Neutralizing Antibody Responses to Canine Distemper Virus Vaccines in Domestic Ferrets (Mustela putorius furo)

One-hundred-fifty pet ferrets, 16 weeks to 8 years of age, were evaluated for the presence of serum-neutralizing (SN) antibody titers against canine distemper virus (CDV) vaccine. All ferrets received an initial vaccine at the source of origin some time before 9 weeks of age, and one or more commercially available CDV vaccines beginning at 14 to 16 weeks of age. SN antibody titers were measured at 1, 2, 3, and > 3 years after each ferret received their last CDV vaccination. Ferrets with titers 4 weeks after vaccination to determine seroconversion to ≥ 1:50 SN titers. Ninety percent (135/150) of the ferrets had titers in excess of 1:50. Ten percent (15/150) of the ferrets had titers 1:50 against CDV for > 3 years after being vaccinated at 14 to 16 weeks of age or older, and there is no significant difference in the ability of 3 brands of CDV vaccine to elicit anti-CDV SN titers.

Evaluation of synthetic infection-enhancing lipopeptides as adjuvants for a live-attenuated canine distemper virus vaccine administered intra-nasally to ferrets

BackgroundInactivated paramyxovirus vaccines have been associated with hypersensitivity responses upon challenge infection. For measles and canine distemper virus (CDV) safe and effective live-attenuated virus vaccines are available, but for human respiratory syncytial virus and human metapneumovirus development of such vaccines has proven difficult. We recently identified three synthetic bacterial lipopeptides that enhance paramyxovirus infections in vitro, and hypothesized these could be used as adjuvants to promote immune responses induced by live-attenuated paramyxovirus vaccines. MethodsHere, we tested this hypothesis using a CDV vaccination and challenge model in ferrets. Three groups of six animals were intra-nasally vaccinated with recombinant (r) CDV5804PL(CCEGFPC) in the presence or absence of the infection-enhancing lipopeptides Pam3CSK4 or PHCSK4. The recombinant CDV vaccine virus had previously been described to be over-attenuated in ferrets. A group of six animals was mock-vaccinated as control. Six weeks after vaccination all animals were challenged with a lethal dose of rCDV strain Snyder-Hill expressing the red fluorescent protein dTomato. ResultsUnexpectedly, intra-nasal vaccination of ferrets with rCDV5804PL(CCEGFPC) in the absence of lipopeptides resulted in good immune responses and protection against lethal challenge infection. However, in animals vaccinated with lipopeptide-adjuvanted virus significantly higher vaccine virus loads were detected in nasopharyngeal lavages and peripheral blood mononuclear cells. In addition, these animals developed significantly higher CDV neutralizing antibody titers compared to animals vaccinated with non-adjuvanted vaccine. ConclusionsThis study demonstrates that the synthetic cationic lipopeptides Pam3CSK4 and PHCSK4 not only enhance paramyxovirus infection in vitro, but also in vivo. Given the observed enhancement of immunogenicity their potential as adjuvants for other live-attenuated paramyxovirus vaccines should be considered.

Accuracy of a point-of-care ELISA test kit for predicting the presence of protective canine parvovirus and canine distemper virus antibody concentrations in dogs

Canine parvovirus (CPV) and canine distemper virus (CDV) are highly infectious and often fatal diseases with worldwide distributions, and are important population management considerations in animal shelters. A point-of-care ELISA test kit is available to detect serum antibodies to CPV and CDV, and presumptively to predict protective status. The aim of this study was to determine the diagnostic accuracy of the test compared to CPV hemagglutination inhibition titers and CDV serum neutralization titers determined by a reference laboratory, using sera collected from dogs housed at animal shelters. The ELISA test was used under both field and laboratory conditions and duplicate specimens were processed using an extra wash step. The test kit yielded accurate results (CPV: sensitivity 92.3%, specificity 93.5%; CDV: sensitivity 75.7%, specificity 91.8%) under field conditions. CDV sensitivity was improved by performing the test under laboratory conditions and using an optical density (OD) meter (laboratory performed 94.0%; OD 88.1%). Point-of-care ELISA testing for serum CPV and CDV antibody titers was demonstrated to be a useful tool for determining antibody status when making decisions regarding the need for CPV and/or CDV vaccination and also in animal shelters for population management.

Development of a combined canine distemper virus specific RT-PCR protocol for the differentiation of infected and vaccinated animals (DIVA) and genetic characterization of the hemagglutinin gene of seven Chinese strains demonstrated in dogs

A combined reverse-transcription polymerase chain reaction (RT-PCR) method was developed for the detection and differentiation of wild-type and vaccine strains of the canine distemper virus (CDV). A pair of primers (P1/P2) was used to detect both CDV wild-type strains and vaccines. Another pair (P3/P4) was used to detect only CDV wild-type strains. A 335bp fragment was amplified from the genomic RNA of the vaccine and wild-type strains. A 555bp fragment was amplified specifically from the genomic RNA of the wild-type strains. No amplification was achieved for the uninfected cells, cells infected with canine parvovirus, canine coronavirus, or canine adenovirus. The combined RT-PCR method detected effectively and differentiated the CDV wild-type and vaccine strains by two separate RT-PCRs. The method can be used for clinical detection and epidemiological surveillance. The phylogenetic analysis of the hemagglutinin gene of the local wild-type CDV strains revealed that the seven local isolates all belonged to the Asia-1 lineage, and were clustered closely with one another at the same location. These results suggested that the CDV genotype Asia-1 is circulating currently in domestic dogs in China.

A multiplex reverse transcription-nested polymerase chain reaction for detection and differentiation of wild-type and vaccine strains of canine distemper virus

A multiplex reverse transcription-nested polymerase chain reaction (RT-nPCR) method was developed for the detection and differentiation of wild-type and vaccine strains of canine distemper virus (CDV). A pair of primers (P1 and P4) specific for CDV corresponding to the highly conserved region of the CDV genome were used as a common primer pair in the first-round PCR of the nested PCR. Primers P2 specific for CDV wild-type strains, were used as the forward primer together with the common reverse primer P4 in the second round of nested PCR. Primers P3, P5 specific for CDV wild-type strain or vaccine strain, were used as the forward primer together with the common reverse primer P4+P6 in the second round of nested PCR. A fragment of 177 bp was amplified from vaccine strain genomic RNA, and a fragment of 247 bp from wild-type strain genomic RNA in the RT-nPCR, and two fragments of 247 bp and 177 bp were amplified from the mixed samples of vaccine and wild-type strains. No amplification was achieved for uninfected cells, or cells infected with Newcastle disease virus (NDV), canine parvovirus (CPV), canine coronavirus (CCV), rabies virus (RV), or canine adenovirus (CAV). The RT-nPCR method was used to detect 30 field samples suspected of canine distemper from Heilongjiang and Jilin Provinces, and 51 samples in Shandong province. As a result of 30 samples, were found to be wild-type-like, and 5 to be vaccine-strain-like. The RT-nPCR method can be used to effectively detect and differentiate wild-type CDV-infected dogs from dogs vaccinated with CDV vaccine, and thus can be used in clinical detection and epidemiological surveillance.

Canine distemper virus detection in asymptomatic and non vaccinated dogs

A quantitative real time polymerase chain reaction (PCR) revealed canine distemper virus presence in peripheral blood samples from asymptomatic and non vaccinated dogs. Samples from eleven domestic dogs with no signs of canine distemper and not vaccinated at the month of collection were used. Canine distemper virus vaccine samples in VERO cells were used as positive controls. RNA was isolated with Trizol®, and treated with a TURBO DNA-free kit. Primers were designed for canine distemper virus nucleocapsid protein coding region fragment amplification (84 bp). Canine b-actin (93 bp) was utilized as the endogenous control for normalization. Quantitative results of real time PCR generated by ABI Prism 7000 SDS Software showed that 54.5% of dogs with asymptomatic canine distemper were positive for canine distemper virus. Dissociation curves confirmed the specificity of the real time PCR fragments. This technique could detect even a few copies of viral RNA and identificate subclinically infected dogs providing accurate diagnosis of this disease at an early stage.

Early life DNA vaccination with the H gene of Canine distemper virus induces robust protection against distemper

Young mink kits (n=8) were vaccinated with DNA plasmids encoding the viral haemagglutinin protein (H) of a vaccine strain of Canine distemper virus (CDV). Virus neutralising (VN) antibodies were induced after 2 immunisations and after the third immunisation all kits had high VN antibody titres. The VN antibody titres remained high for more than 4 months and the mink were protected against viraemia, lymphopenia, clinical disease and changes in the percentage of IFN-γ producing peripheral blood leucocytes after challenge inoculation with a recent wild type strain of CDV. Essentially, these results demonstrate that early life DNA vaccination with the H gene of a CDV vaccine strain induced robust protective immunity against a recent wild type CDV.

Humoral and cell-mediated immune responses in DNA immunized mink challenged with wild-type canine distemper virus

The aim of the study was to investigate the different phases of the immune response after DNA immunization with the hemagglutinin and nucleoprotein genes from canine distemper virus (CDV). Although attenuated live CDV vaccines have effectively reduced the incidence of disease, canine distemper is still a problem worldwide. The broad host range of CDV creates a constant viral reservoir among wildlife animals. Our results demonstrated early humoral and cell-mediated immune responses (IFN-gamma) in DNA vaccinated mink compared to mock-vaccinated mink after challenge with a Danish wild-type CDV. The DNA vaccine-induced immunity protected the natural host against disease development.

Detecção do vírus da cinomose canina por RT-PCR utilizando-se oligonucleotídeos para os genes da fosfoproteína, hemaglutinina e neuraminidase

Empregou-se a técnica de reação em cadeia pela polimerase precedida de transcrição reversa para detecção do vírus da cinomose canina (CC). Para a padronização da técnica foram selecionados quatro pares de oligonucleotídeos (P1, P2, N1, H1), baseados em seqüências dos genes da fosfoproteína, neuraminidase e hemaglutinina, sendo utilizadas três cepas vacinais de vírus da CC como controles positivos. Foram analisadas três amostras isoladas de cães com cinomose e quatro amostras provenientes de cães com suspeita clínica de cinomose. Não houve amplificação nas amostras com suspeita clínica da doença. Os resultados obtidos com os oligonucleotídeos P1 e N1 foram superiores aos de H1. Os oligonucleotídeos P2 foram considerados inapropriados para a detecção do vírus da CC. Os amplicons obtidos com os oligonucleotídeos P1, N1 e H1 foram clivados com endonucleases de restrição, sendo os perfis das amostras virais comparados aos da amostra vacinal Lederle, utilizada como referência. Um padrão similar de restrição foi observado em todas as amostras analisadas.

Immunization of Puppies in the Presence of Maternally Derived Antibodies Against Canine Distemper Virus

SummaryVaccination of dams with modified-live canine distemper virus (CDV) vaccines will elicit high concentrations of colostral antibody, that although vital for protection of the pup during the first weeks of life, can interfere with active vaccination against the virus. In the present study, 12 pups, 7–9 weeks of age, with maternally derived immunity to CDV, were vaccinated with a canarypox-vectored CDV vaccine. These pups were protected against intravenous challenge with CDV. Three littermate pups that were unvaccinated all developed clinical signs of infection after challenge, and two of these control pups died.

SEROLOGIC RESPONSE TO A CANARYPOX-VECTORED CANINE DISTEMPER VIRUS VACCINE IN THE GIANT PANDA (AILUROPODA MELANOLEUCA)

The giant panda (Ailuropoda melanoleuca) is known to be susceptible to natural infection with canine distemper virus (CDV). Vaccination of giant pandas with conventional modified live CDV vaccines has been avoided due to the numerous carnivore species known to have become infected with CDV after vaccination. Serum-neutralizing antibodies to CDV were measured after s.c. and i.m. annual vaccination with a canarypox-vectored recombinant CDV vaccine in an adult male and female giant panda over the period of 2 yr. The vaccine proved to be safe, and serum-neutralizing antibody titers interpreted as protective against CDV disease were measured in each animal.

SEROLOGIC RESPONSES AFTER VACCINATION OF FENNEC FOXES (VULPES ZERDA) AND MEERKATS (SURICATA SURICATTA) WITH A LIVE, CANARYPOX-VECTORED CANINE DISTEMPER VIRUS VACCINE

Fennec foxes (Vulpes zerda) and meerkats (Suricata suricatta) are considered to be susceptible to canine distemper virus (CDV) infection. Although no definitive clinical cases of natural CDV infections have been reported, mortalities due to CDV have been suspected and are reported in other closely related species. A commercially available monovalent, live, canarypox-vectored CDV vaccine induced neutralizing antibody titers that were maintained for at least a year in both fennec foxes and meerkats.

The fusion protein of wild-type canine distemper virus is a major determinant of persistent infection

The wild-type A75/17 canine distemper virus (CDV) strain induces a persistent infection in the central nervous system but infects cell lines very inefficiently. In contrast, the genetically more distant Onderstepoort CDV vaccine strain (OP-CDV) induces extensive syncytia formation. Here, we investigated the roles of wild-type fusion (F WT) and attachment (H WT) proteins in Vero cells expressing, or not, the canine SLAM receptor by transfection experiments and by studying recombinants viruses expressing different combinations of wild-type and OP-CDV glycoproteins. We show that low fusogenicity is not due to a defect of the envelope proteins to reach the cell surface and that H WT determines persistent infection in a receptor-dependent manner, emphasizing the role of SLAM as a potent enhancer of fusogenicity. However, importantly, F WT reduced cell-to-cell fusion independently of the cell surface receptor, thus demonstrating that the fusion protein of the neurovirulent A75/17-CDV strain plays a key role in determining persistent infection.

Induction of castration by immunization of male dogs with recombinant gonadotropin-releasing hormone (GnRH)-canine distemper virus (CDV) T helper cell epitope p35

Immunocastration is a considerable alternative to a surgical castration method especially in male animal species for alleviating unwanted male behaviors and characteristics. Induction of high titer of antibody specific for gonadotropin-releasing hormone (GnRH) correlates with the regression of testes. Fusion proteins composed of canine GnRH and T helper (Th) cell epitope p35 originated from canine distemper virus (CDV) F protein and goat rotavirus VP6 protein were produced in E. coli. When these fusion proteins were injected to male dogs which were previously immunized with CDV vaccine, the fusion protein of GnRH-CDV Th cell epitope p35 induced much higher antibody than that of GnRH-rotavirus VP6 protein or GnRH alone. The degeneration of spermatogenesis was also verified in the male dogs immunized with the fusion protein of GnRH-CDV Th cell epitope p35. These results indicate that canine GnRH conjugated to CDV Th cell epitope p35 acted as a strong immunogen and the antibody to GnRH specifically neutralized GnRH in the testes. This study also implies a potential application of GnRH-based vaccines for immunocastration of male pets.

Early DNA vaccination of puppies against canine distemper in the presence of maternally derived immunity

Canine distemper (CD) is a disease in carnivores caused by CD virus (CDV), a member of the morbillivirus genus. It still is a threat to the carnivore and ferret population. The currently used modified attenuated live vaccines have several drawbacks of which lack of appropriate protection from severe infection is the most outstanding one. In addition, puppies up to the age of 6–8 weeks cannot be immunized efficiently due to the presence of maternal antibodies. In this study, a DNA prime modified live vaccine boost strategy was investigated in puppies in order to determine if vaccinated neonatal dogs induce a neutralizing immune response which is supposed to protect animals from a CDV challenge. Furthermore, a single DNA vaccination of puppies, 14 days after birth and in the presence of high titers of CDV neutralizing maternal antibodies, induced a clear and significant priming effect observed as early as 3 days after the subsequent booster with a conventional CDV vaccine. It was shown that the priming effect develops faster and to higher titers in puppies preimmunized with DNA 14 days after birth than in those vaccinated 28 days after birth. Our results demonstrate that despite the presence of maternal antibodies puppies can be vaccinated using the CDV DNA vaccine, and that this vaccination has a clear priming effect leading to a solid immune response after a booster with a conventional CDV vaccine.

Incidence of adverse events in ferrets vaccinated with distemper or rabies vaccine: 143 cases (1995-2001).

To determine the incidence of adverse events in ferrets vaccinated with a modified-live avian cell culture canine distemper virus vaccine licensed for use in ferrets, an inactivated rabies vaccine licensed for use in ferrets, or both. Retrospective study. 143 ferrets. Medical records were reviewed to identify ferrets that had an adverse event after vaccination. Adverse events developed within 25 minutes after vaccination in 13 ferrets. One ferret developed an adverse event after receiving a distemper and a rabies vaccine simultaneously and developed a second adverse event the following year after receiving the rabies vaccine alone. Therefore, a total of 14 adverse events were identified. All adverse events were an anaphylactic reaction characterized by generalized hyperemia, hypersalivation, and vomiting. Ten of the 14 anaphylactic reactions occurred after ferrets received both vaccines, 3 occurred after ferrets received the distemper vaccine alone, and 1 occurred after a ferret received the rabies vaccine alone. Incidences of adverse events after administration of both vaccines, the distemper vaccine alone, and the rabies vaccine alone were 5.6, 5.9, and 5.6%, respectively. Ferrets that had an anaphylactic reaction were significantly older at the time of vaccination than were ferrets that did not. Results suggest that there may be a high incidence of anaphylactic reactions after vaccination of domestic ferrets. Ferrets should be observed for at least 25 minutes after vaccination, and veterinarians who vaccinate ferrets should be prepared to treat anaphylactic reactions.

Vaccination of puppies with a lipid-formulated plasmid vaccine protects against a severe canine distemper virus challenge

We assessed whether the formulation of a DNA vaccine expressing the canine distemper virus (CDV) hemagglutinin (HA) and fusion (F) immunogens with the cationic lipid DMRIE-DOPE could induce serological responses and protection against a severe CDV challenge in the dog. Although clear protection was observed in dogs vaccinated with formulated plasmids only limited CDV specific antibody titers were observed in protected dogs before challenge, suggesting that protection could be explained by cell-mediated immunity and/or by a strong antibody-based memory response (priming) triggered by the infectious challenge. The high level of protection achieved in this study, demonstrated that formulated DNA CDV vaccines can generate in dogs a level a protection comparable to conventional CDV vaccines.