Clinical and serological response of wild dogs (Lycaon pictus) to vaccination against canine distemper,canine parvovirus infection and rabies

Wild dogs Lycaon pictuis (n = 8) were vaccinated 4 times against canine distemper (n = 8) (initially with inactivated and subsequently with live attenuated strains of canine distemper) and canine parvovirus infection (n = 8) over a period of 360 days. Four of the wild dogs were also vaccinated 3 times against rabies using a live oral vaccine and 4 with an inactivated parenteral vaccine. Commercially-available canine distemper, canine parvovirus and parenteral rabies vaccines, intended for use in domestic dogs, were used. None of the vaccinated dogs showed any untoward clinical signs. The inactivated canine distemper vaccine did not result in seroconversion whereas the attenuated live vaccine resulted in seroconversion in all wild dogs. Presumably protective concentrations of antibodies to canine distemper virus were present in all wild dogs for at least 451 days. Canine parvovirus haemagglutination inhibition titres were present in all wild dogs prior to the administration of vaccine and protective concentrations persisted for at least 451 days. Vaccination against parvovirus infection resulted in a temporary increase in canine parvovirus haemagglutination inhibition titres in most dogs. Administration of both inactivated parenteral and live oral rabies vaccine initially resulted in seroconversion in 7 of 8 dogs. These titres, however, dropped to very low concentrations within 100 days. Booster administrations resulted in increased antibody concentrations in all dogs. It was concluded that the vaccines were safe to use in healthy subadult wild dogs and that a vaccination protocol in free-ranging wild dogs should at least incorporate booster vaccinations against rabies 3-6 months after the first inoculation.     

Cell-mediated immunity and age at vaccination associated with measles inoculation and protection of dogs against canine distemper.

The antibody-mediated immune response (AMIR) of dogs to measles and canine distemper viruses has been described. However, there is little information on the cell-mediated immune response (CMIR). The AMIR and the CMIR of dogs to canine distemper and to measles were examined. The CMIR was determined for 6 weeks by measuring the 3H-thymidine uptake by immune lymphocytes in the lymphocyte transformation test. Concurrently, canine distemper and measles virus serum-neutralization antibodies were measured by a microtitration serum-neutralization test. Dogs vaccinated with canine distemper virus had a CMIR and an AMIR to canine distemper. However, measles virus-vaccinated dogs had only a CMIR to canine distemper. A CMIR in the absence of an AMIR indicates that cell-mediated immunity is the most important immune mechanism in protecting measles virus-vaccinated dogs against canine distemper. Development of CMIR and AMIR to canine distemper and measles antigens depended on the age of the dog at the time of vaccination. Adult and juvenile dogs had immune responses to both canine distemper and measles. Neither virus, however, elicited an immune response in neonates.     

Evaluation of the efficacy and duration of immunity of a canine combination vaccine against virulent parvovirus, infectious canine hepatitis virus, and distemper virus experimental challenges

The results of this study confirmed that dogs vaccinated subcutaneously with a commercially available multivalent vaccine containing modified-live canine distemper virus, canine adenovirus type 2, canine parvovirus type 2b, and canine parainfluenza virus antigens were protected against sequential experimental challenge 55 to 57 months after initial vaccination given at 7 to 8 weeks of age. All 10 vaccinates were protected against clinical diseases and mortality following parvovirus and infectious canine hepatitis experimental infections. All vaccinates were protected against mortality and 90% against clinical disease following distemper challenge. These data support at least a 4-year duration of immunity for these three "core" fractions in the combination vaccine.     

Evaluation of a dot ELISA kit for measuring immunoglobulin M antibodies to canine parvovirus and distemper virus

A dot ELISA for the detection of immunoglobulin M (IgM) antibodies to canine distemper virus (CDC) and canine parvovirus (CPV) was assessed. The titres of IgM antibodies to CDV and CPV in 100 dogs were measured by the Immunocomb ELISA kit and compared with the results derived from the immunofluorescence assay (IFA). There was a strong correlation between the results of the dot ELISA technique and the IFA (P < 0.001). The dot ELISA kit was also used to assess the changes in the levels of immunoglobulin G (IgG) and IgM antibodies to CPV and CDV in 10 puppies vaccinated with a polyvalent vaccine. High levels of IgM antibodies to CPV were first detected seven days after they were vaccinated, and after nine days all the pups had high titres of IgG antibodies to CPV. High levels of IgM antibodies to CDV were detected after nine days and the highest average titres were recorded after 12 days. IgG antibodies to CDV were present from nine days after vaccination.     

Compatibility of a bivalent modified-live vaccine against Bordetella bronchiseptica and CPiV, and a trivalent modified-live vaccine against CPV, CDV and CAV-2

Eight puppies (group 1) were vaccinated once with a bivalent modified-live vaccine against infectious tracheobronchitis by the intranasal route and at the same time with an injectable trivalent vaccine against canine parvovirus, canine distemper virus and canine adenovirus; a second group of eight puppies (group 2) was vaccinated only with the intranasal bivalent vaccine, and a further eight puppies (group 3) were vaccinated only with the injectable trivalent vaccine. Three weeks later they were all challenged with wildtype Bordetella bronchiseptica and canine parainfluenza virus by the aerosol route, and their antibody responses to the five vaccine organisms were determined. Oronasal swabs were taken regularly before and after the challenge for the isolation of bacteria and viruses, and the puppies were observed for clinical signs for three weeks after the challenge. There were no significant differences in the puppies' titres against canine parvovirus, canine distemper virus and canine adenovirus type 2 between the groups vaccinated with or without the bivalent intranasal vaccine. After the challenge the mean clinical scores of the two groups vaccinated with the intranasal vaccine were nearly 90 per cent lower (P=0.001) than the mean score of the group vaccinated with only the trivalent injectable vaccine, and the puppies in this group all became culture-positive for B bronchiseptica and canine parainfluenza virus. There were only small differences between the rates of isolation of B bronchiseptica from groups 1, 2 and 3, but significantly lower yields of canine parainfluenza virus were isolated from groups 1 and 2 than from group 3.     

Serum antibody response to canine parvovirus, canine adenovirus-1, and canine distemper virus in dogs with known status of immunization: study of dogs in Sweden

Serum antibody titers to canine parvovirus (CPV), canine adenovirus-1 (CAV-1), and canine distemper virus (CDV) were measured in dogs with known immunization status. The dogs represented 3 groups: nonvaccinated dogs less than 12 months old; vaccinated dogs less than 12 months old; and adult dogs greater than 12 months old. For practical reasons, the population from which the specimens were obtained could be considered as free from natural infection with CAV-1 and CDV. In nonvaccinated dogs less than 12 months old, antibodies against all 3 viruses were measured at the time the dogs were given their first vaccination. Altogether, 50.7% of the dogs had titer greater than or equal to 1:10 to CPV, and 26.1 and 46.2% had titer greater than or equal to 1:8 to CAV-1 and CDV, respectively. The concentration of maternal antibody seemed to be of major importance for failure of immunization with use of inactivated CPV vaccine, but not with CAV-1 and CDV vaccination. In dogs less than 12 months old and vaccinated against CPV infection with inactivated virus, only 11.5% had titer greater than or equal to 1:80. In dogs vaccinated against infectious canine hepatitis and canine distemper, 63.2 and 78.3%, respectively, had titer greater than or equal to 1:16. In adult dogs greater than 2 months old and vaccinated against CPV infection, less than 50% had titer greater than or equal to 1:80, regardless of time after vaccination. There was no significant difference in titer between vaccinated and nonvaccinated dogs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum antibody titres to canine parvovirus, adenovirus and distemper virus in dogs in the UK which had not been vaccinated for at least three years

Antibody titres to canine distemper (CDV), canine parvovirus (CPV) and canine adenovirus (CAV) were measured in 144 adult dogs that had not been vaccinated for between three and 15 years. Protective antibodies to CPV were present in 95 per cent of the population, to CDV in 71.5 per cent and to CAV in 82 per cent. The prevalence of protective titres did not decrease with increasing time interval from the last vaccination for any of the three diseases studied. Booster vaccination increased the dogs CAV titres. For comparative purposes, 199 puppies were sampled at the time of their first and second vaccination. In the case of CPV and CAV a significantly higher proportion of the adult dogs were protected than of the puppies immediately after they were vaccinated. Natural CPV boosting was strongly suspected because the dogs had significantly higher titres three years after their primary vaccination than two weeks after it and three unvaccinated dogs had acquired protective antibody levels uneventfully. There was no evidence of natural exposure to CDV.     

Serologic response of maned wolves (Chrysocyon brachyurus) to canine and canine parvovirus vaccination distemper virus.

This study evaluated the immune response of 47 (22 males, 25 females) captive maned wolves (Chrysocyon brachyurus) to modified-live canine parvovirus and canine distemper virus (Onderstepoort and Rockborn strains) vaccines. Sera were collected from 33 adults and 14 pups, including five free-ranging pups captured at 1 yr of age or younger. All the adults and four captive-born pups had been vaccinated prior to this first blood collection. Virus neutralization and hemagglutination-inhibition assays were performed for quantitating antibodies against canine distemper and canine parvovirus, respectively. Distemper antibody titers > or = 100 were present in 57% of adults and 14% of pups. All adults and 29% of pups had parvovirus antibody titers > or = 80. After vaccination, 72% of the wolves developed antibody titers > or = 100 against distemper and 98% developed titers > or = 80 against parvovirus. Both vaccines used were safe and immunogenic to juvenile and adult maned wolves, regardless of prior vaccination history.     

The humoral immune response to recombinant nucleocapsid antigen of canine distemper virus in dogs vaccinated with attenuated distemper virus or DNA encoding the nucleocapsid of wild-type virus

This study compared the humoral immune response against the nucleocapsid-(N) protein of canine distemper virus (CDV) of dogs vaccinated with a multivalent vaccine against parvo-, adeno-, and parainfluenza virus and leptospira combined with either the attenuated CDV Onderstepoort strain (n = 15) or an expression plasmid containing the N-gene of CDV (n = 30). The vaccinations were applied intramuscularly three times at 2-week intervals beginning at the age of 6 weeks. None of the pre-immune sera recognized the recombinant N-protein, confirming the lack of maternal antibodies at this age. Immunization with DNA vaccine for CDV resulted in positive serum N-specific IgG response. However, their IgG (and IgA) titres were lower than those of CDV-vaccinated dogs. Likewise, DNA-vaccinated dogs did not show an IgM peak. There was no increase in N-specific serum IgE titres in either group. Serum titres to the other multivalent vaccine components were similar in both groups.     

Evaluation of ELISA based on the conserved and functional middle region of nucleocapsid protein to detect distemper infection in dogs

A 287 bp fragment from the middle region of the nucleocapsid protein of canine distemper virus (CDV) was amplified from the conjunctival samples of distemper-infected dogs and was cloned into pRSET B vector. The recombinant protein was expressed as a 16-kDa-fusion protein with histidine tag in E. coli. Sera of distemper-infected and vaccinated dogs contained IgG antibodies against the purified recombinant protein as observed by enzyme linked immunosorbent assays (ELISA) and showed a strong correlation (r = 0.882, p < 0.0001 at 95% CI) and good agreement (kappa = 0.718) with the conventional tissue culture viral antigen based ELISA. Further, the results of recombinant protein based ELISA and Western blotting with the sera from the infected and vaccinated dogs correlated well (kappa = 0.8226). These findings recommend the use of the recombinant protein in the serodiagnosis of canine distemper virus infection in dogs.     

犬瘟热的诊断及其预防免疫的研究进展

本文对犬瘟热（CD）的诊断、预防免疫和免疫失败的影响因素及犬瘟热病毒（CDV）的宿主范围进行了综述。CDV不仅感染陆生食肉动物，而且也感染水生食肉动物，并且其宿主范围还在不断扩大。CDV感染主要采用病毒分离、特异性病毒抗原或特异性核酸检测等方法确诊。疫苗包括灭活的CDV疫苗、麻疹病毒（MV）异源苗及CDV弱毒活苗。疫苗接种犬的免疫反应主要取决于毒株特性及犬的应答能力，只有弱毒活苗能诱导产生持久而坚强的保护力。尽管多年来CDV弱毒活苗的使用控制了CD的发生，但最近免疫过的犬发生CD的病例并不少见。分析免疫失败的原因，主要是母源抗体干扰、疫苗质量差、其它病毒的免疫抑制以及CDV流行株可能发生了变异等因素的影响。     

Development of hypertrophic osteodystrophy and antibody response in a litter of vaccinated Weimaraner puppies

Two different vaccination protocols were compared with regard to the development of hypertrophic osteodystrophy (HOD) (also termed metaphyseal osteopathy) and effectiveness of immunisation in a litter of 10 Weimaraner puppies. Five puppies (group 1) were vaccinated with a modified live canine parvovirus vaccine (CPV) and then two weeks later with a trivalent vaccine containing modified live canine distemper virus and adenovirus type 2 combined with a Leptospira bacterin (DHL). The CPV and DHL vaccine protocols were administered a further two times, at two-week intervals. Group 2 was vaccinated with three consecutive multivalent vaccines containing modified live canine distemper virus, canine parvovirus, parainfluenza and adenovirus type 2 combined with a Leptospira bacterin, at four-week intervals. All puppies were first vaccinated at the age of eight weeks. Three dogs in group 1 developed HOD, while all five dogs in group 2 developed HOD during the study period. Dogs in group 2 had more episodes of HOD than those in group 1. Dogs in group 1 developed higher antibody titres to canine distemper virus and parvovirus compared with those in group 2. Only two out of the 10 dogs developed protective antibody titres to parvovirus. The results of this study suggest that the two different vaccination protocols affected the pattern of appearance of HOD and immunisation in this litter of Weimaraner puppies. The results obtained and the previously reported data suggest that a larger controlled study is needed to further elucidate the effect of different vaccination protocols on HOD and immunisation in Weimaraner puppies.     

Natural distemper in vaccinated and unvaccinated dogs in Warsaw

Two hundred and twenty-four dogs with clinical signs of distemper were examined for the presence of canine distemper virus (CDV) in mucous membranes by direct immunofluorescence assay. The study showed that 22% of the animals were CDV-positive. Most (33/50; 66%) of the infected dogs had never been vaccinated against distemper, whereas only 11 of 50 (22%) CDV-positive animals were immunized at least once. The difference in the infection rate between vaccinated and unvaccinated animals was statistically significant (P < 0.001), as assessed by the chi2 test. It is concluded that distemper is an important disease among dogs in Warsaw and the vaccination significantly reduces the risk of this disease.     

Measles vaccine in dogs: efficacy against aerosol challenge with virulent canine distemper virus.

Fifty young Beagle pups were used in studies on the efficacy of measles virus vaccine in providing protection against virulent canine distemper (CD) virus given intranasally. Among 29 dogs vaccinated with measles virus vaccine and subsequently exposed to virulent CD virus, 1 died, 7 developed relatively severe signs of CD, 15 had mild signs of distemper, and 6 remained clinically normal. Of 15 unvaccinated dogs similarly exposed to virulent CD virus, 11 succumbed to distemper. Six pups vaccinated with modified live-virus (MLV) CD virus vaccine remained clinically normal following immunity challenge.     

Detection of canine distemper viral antigen in formalin-fixed and paraffin-embedded tissue of a fitch (Mustela putorius), using an immunoperoxidase technique

The present study describes how a naturally infected fitch (Mustela putorius) caused an outbreak of canine distemper in a colony of insufficiently vaccinated dogs. The detection of canine distemper virus (CDV) on paraffin sections of different organs of the fitch and one of the dead dogs was achieved using a monoclonal antibody against the nucleocapsid protein (NP) of CDV and the avidin-biotin-peroxidase complex (ABC) technique.     

Chronic encephalomyelitis caused by canine distemper virus in a Bengal tiger

A chronic progressive neurologic disease was observed and monitored for 18 months in a young, tamed Bengal tiger. Clinical, serologic, and neuropathologic evidence of canine distemper virus infection was seen. Clinical signs included convulsions, myoclonus, and slowly progressive ataxia. Marked increases in neutralizing antibodies against canine distemper virus were seen in the serum and cerebrospinal fluid. Neuropathologic findings were nonsuppurative meningoencephalomyelitis, with perivascular cuffing, demyelination, and inclusion bodies typical of canine distemper virus. It was concluded that, in light of this case and an earlier report of canine distemper in lion cubs, vaccination of this subgroup of carnivores with a killed vaccine may be beneficial if exposure to other animals susceptible to canine distemper is anticipated.     

Prophylactic, postinfectious and neonatal vaccination against canine distemper in mink.

Mink were vaccinated against canine distemper and challenged with the Snyder Hill strain of canine distemper virus. Protection was acquired if vaccination took place more than a few days before challenge. If vaccination took place even early during incubation mortality was higher than in the unvaccinated controls. Full protection of kits may be achieved even at an age of 16 to 20 days provided the kits had not passively acquired immunity from their mothers. Kits surviving distemper because of passively acquired immunity may not actively acquire immunity during infection and may die at a later exposure.     

Three-year duration of immunity in dogs following vaccination against canine adenovirus type-1, canine parvovirus, and canine distemper virus

A challenge-of-immunity study was conducted to demonstrate immunity in dogs 3 years after their second vaccination with a new multivalent, modified-live vaccine containing canine adenovirus type 2 (CAV-2), canine parvovirus (CPV), and canine distemper virus (CDV). Twenty-three seronegative pups were vaccinated at 7 and 11 weeks of age. Eighteen seronegative pups, randomized into groups of six dogs, served as challenge controls. Dogs were kept in strict isolation for 3 years following the vaccination and then challenged sequentially with virulent canine adenovirus type 1 (CAV-1), CPV, and CDV. For each viral challenge, a separate group of six control dogs was also challenged. Clinical signs of CAV-1, CPV, and CDV infections were prevented in 100% of vaccinated dogs, demonstrating that the multivalent, modified-live test vaccine provided protection against virulent CAV-1, CPV, and CDV challenge in dogs 7 weeks of age or older for a minimum of 3 years following second vaccination.     

水貂犬瘟热流行病学调查

为了调查山东省水貂犬瘟热的流行病学情况,对2010年8月－2012年8月期间由诸城、文登等地养貂场送诊的996份水貂病例进行了临床诊断和病原学检查。结果显示,共检出犬瘟热病毒阳性病料223份,阳性率为22.39%。其中,犬瘟热病毒与其他病原混合感染136例,占阳性病例的60.99%;阳性样本中未免疫病例116个;诸城检出阳性病例数最多,为147例;3月龄水貂发病率最高,占阳性病例的43.0%;水貂感染犬瘟热病毒主要症状为眼、鼻黏液性分泌物增多、脚垫增厚、呼吸困难;主要病理变化为肠、脑部出血。结果表明,犬瘟热依然是危害水貂养殖的重要疫病,且犬瘟热病毒易与其他病原混合感染;免疫接种能有效预防水貂犬瘟热,且宜在3月龄以前进行。     

Lymphocyte-associated immune responses to canine distemper and measles viruses in distemper-infected gnotobiotic dogs.

Cellular immune responses of peripheral blood lymphocytes to canine distemper virus and measles virus were determined in vaccinated or infected gnotobiotic dogs, using the technique of syncytia inhibition. Cross-reactivity between viruses was detected in both groups of dogs. Peak responses in vaccinated dogs occurred 11 days after vaccination and declined to base-line levels by 3 weeks, whereas responses in infected dogs were present 30 days after inoculation. Fractionation experiments with peripheral blood lymphocytes indicated that synctia inhibition is probably mediated by T lymphocytes.