Antibody response to modified-live canine adenovirus vaccine in African hunting dogs (Lycaon pictus).

Nine hunting dogs were bled pre and post vaccination with modified-live virus vaccine. Their antibody responses to canine adenovirus type 1 was measured by an indirect immunofluorescent antibody test. The vaccine proved to be both effective and safe.     

Response of pups to modified-live canine parvovirus component in a combination vaccine

Twenty-eight pups from a general pet population were vaccinated for canine parvovirus (CPV) with a combination vaccine every 3 weeks until the pups were 11 to 16 weeks old. Canine parvovirus antibody titers were measured by serum neutralization before each vaccination and greater than or equal to 2 weeks after the final vaccination. Eighteen pups that initially were seronegative for CPV seroconverted after 1 to 3 doses of modified-live virus CPV vaccine administered when the pups were between 8 and 16 weeks old; 16 of 18 seroconverted after the 1st dose. Of 10 pups that were seropositive for CPV at initial examination, 7 did not develop protective titers after 3 doses of vaccine, with the last dose given when the pups were 14 to 16 weeks old. Maternally derived antibody was the primary cause of vaccination failure.     

Safety, efficacy, and immunogenicity of a modified-live equine influenza virus vaccine in ponies after induction of exercise-induced immunosuppression

OBJECTIVE: To determine safety, efficacy, and immunogenicity of an intranasal cold-adapted modified-live equine influenza virus vaccine administered to ponies following induction of exercise-induced immunosuppression. DESIGN: Prospective study. ANIMALS: Fifteen 9- to 15-month old ponies that had not had influenza. PROCEDURE: Five ponies were vaccinated after 5 days of strenuous exercise on a high-speed treadmill, 5 were vaccinated without undergoing exercise, and 5 were not vaccinated or exercised and served as controls. Three months later, all ponies were challenged by nebulization of homologous equine influenza virus. Clinical and hematologic responses and viral shedding were monitored, and serum and nasal secretions were collected for determination of influenza-virus-specific antibody isotype responses. RESULTS: Exercise caused immunosuppression, as indicated by depression of lymphocyte proliferation in response to pokeweed mitogen. Vaccination did not result in adverse clinical effects, and none of the vaccinated ponies developed clinical signs of infection following challenge exposure. In contrast, challenge exposure caused marked clinical signs of respiratory tract disease in 4 control ponies. Vaccinated and control ponies shed virus after challenge exposure. Antibody responses to vaccination were restricted to serum IgGa and IgGb responses in both vaccination groups. After challenge exposure, ponies in all groups generated serum IgGa and IgGb and nasal IgA responses. Patterns of serum hemagglutination inhibition titers were similar to patterns of IgGa and IgGb responses. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that administration of this MLV vaccine to ponies with exercise-induced immunosuppression was safe and that administration of a single dose to ponies provided clinical protection 3 months later.     

Safety of a modified-live combination vaccine against respiratory and reproductive diseases in pregnant cows

A combination vaccine (Bovi-Shield FP4 + L5, Pfizer Animal Health) containing modified-live virus (MLV) components against bovine herpesvirus-1 (BHV-1), bovine viral diarrhea virus BVDV), parainfluenza virus-3 (PI3), bovine respiratory syncytial virus (BRSV), and inactivated cultures of Leptospira canicola, grippotyphosa, hardjo, icterohaemorrhagiae, and pomona was evaluated for safety in pregnant beef and dairy animals. Heifers vaccinated prebreeding with the minimum immunizing dose (lowest antigen level initiating immunizing effects) of the vaccine's MLV BHV-1 or BVDV components and during pregnancy (approximately 200 days of gestation) with vaccine containing 10x doses of the same BHV-1 and BVDV components delivered live, healthy calves that were determined to be serologically negative (titer less than 1:2) for neutralizing antibodies to BHV-1 and BVDV prior to nursing. Additionally, in three field safety studies, previously vaccinated cows and heifers that received a field dose (vaccine containing antigen levels required for commercial sale of the MLV combination vaccine during either the first, second, or third trimester of pregnancy had abortion rates similar to those of pregnant cows and heifers vaccinated during the same stage of pregnancy with sterile water diluent.     

High-cell-passage canine coronavirus vaccine providing sterilising immunity

OBJECTIVES: To evaluate the ability of a high-cell-passage canine coronavirus vaccine to immunise dogs against challenge with a field isolate of the virus. METHODS: Three dogs that had previously tested seronegative and virus-negative for canine coronavirus were inoculated twice, at 21-day intervals, with the vaccine and kept under observation. Two seronegative and virus-negative dogs served as unvaccinated controls. For safety tests, two additional dogs were inoculated oronasally with 10 times the vaccinal dose and no reactions were observed. Faecal samples were collected daily from the vaccinated dogs after the first and second inoculations. Both vaccinated and control dogs were challenged two weeks after the second vaccination with a field canine coronavirus strain. Blood samples were collected for serological tests before vaccination and at weekly intervals after vaccinations and challenge. RESULTS: Virus was not detected in faecal samples after the first or second vaccinations by virus isolation assays and PCR. Significantly, the vaccinated dogs did not have clinical signs after challenge and no virus shedding was observed. The two unvaccinated control dogs had moderate enteritis, and virus was detected in cell cultures starting from three days postchallenge (dog 1) and two days postchallenge (dog 2), and by PCR for 23 median days. CLINICAL SIGNIFICANCE: This study showed the efficacy of a high-cell-passage canine coronavirus vaccine in preventing infection of dogs by virulent virus and, specifically, its ability to induce sterilising immunity.     

Response of pups with maternal derived antibody to modified-live canine parvovirus vaccine

The AA reports the results of vaccination against canine parvovirus (CPV) of pups with maternal antibody, utilizing a modified-live virus (MLV) CPV vaccine having a titer of 10⁷ TCID₅₀/dose. This vaccine was shown to be effective also when HI antibody titers of pups were ≤ 1:80.     

浒苔多糖对犬冠状病毒灭活苗的免疫增强作用

采用水煮醇沉法提取浒苔多糖,用PMP柱前衍生高效液相色谱串联质谱仪测浒苔多糖组成成分和含量,在犬冠状病毒(canine coronavirus,CCV)灭活苗中添加不同剂量的浒苔多糖,制备犬冠状病毒多糖灭活疫苗。选取30只40日龄的健康土狗随机分成6组,每组5只,Ⅰ~Ⅳ组为浒苔多糖疫苗组(浒苔多糖含量为10,20,30,40g/L),Ⅴ组为浒苔多糖对照组(浒苔多糖含量为30g/L),Ⅵ组为不含浒苔多糖组,各组分别于免疫后7,14,21,35,42,49,56d采血,进行犬冠状病毒抗体效价、淋巴细胞比率、淋巴细胞转化率、IL-2和IFN-γ各指标检测。结果表明,分离纯化后浒苔多糖含量为69.2%,浒苔多糖有6种成分,主要是鼠李糖和木糖;Ⅰ~Ⅴ组各指标均显著高于Ⅵ组(P<0.05),Ⅳ组各指标显著高于其他各组(P<0.05)。由此表明浒苔多糖可以显著提高犬对犬冠状病毒灭活疫苗的免疫作用,浒苔多糖用量对疫苗免疫作用有影响,这为浒苔多糖作为免疫增强剂的开发奠定基础。     

M gene evolution of canine coronavirus in naturally infected dogs

Two stray pups (A and B), three and five months old, respectively, both naturally infected with canine coronavirus (CCoV), were studied for 180 days. The virus was detected intermittently in the pups' faeces by PCR for periods of 156 and 146 days, respectively. Sequence analysis of a fragment of the gene encoding the M protein revealed that the viruses detected at the onset of the infection were very similar to typical strains of CCoV, whereas from 42 days after infection in pup A and 40 days after infection in pup B the viruses had nucleotide and amino acid mutations resembling sequences in feline coronavirus.     

The seroprevalence of canine respiratory coronavirus and canine influenza virus in dogs in New Zealand

Abstract

AIM: To determine whether canine respiratory coronavirus (CRCoV) and canine influenza virus (CIV) are present in dogs in New Zealand.

METHODS: Serum samples from 251 dogs of varying age, breed and clinical histories were tested for the presence of antibodies to CRCoV and CIV, using indirect fluorescent antibody (IFA) analysis. The population sampled represented a wide geographic area but principally encompassed the central and lower North Island of New Zealand.

RESULTS: Seventy-three of the 251 samples (29%) were seropositive for CRCoV. Dogs <2 years old were less likely to be seropositive for CRCoV than older dogs. None was seropositive for CIV.

CONCLUSIONS: This study revealed the presence of antibodies to CRCoV in dogs in New Zealand. Young dogs are less likely to be seropositive than older dogs, probably due to increased opportunity for exposure to CRCoV over time. Serum antibodies to CIV were not detected in any of the dogs sampled, suggesting that this virus is unlikely to be present in dogs in New Zealand.

CLINICAL RELEVENCE: Canine respiratory coronavirus is present in New Zealand. Although the role of this virus in canine infectious tracheobronchitis has not been fully elucidated, evidence suggests that it may have a causal role in this disease. Veterinarians should consider CRCoV as a differential diagnosis in cases of respiratory disease in dogs in New Zealand. While CIV appears not to be currently present in New Zealand, veterinarians should consider infection with this virus as a differential diagnosis in dogs presenting with respiratory signs.     

辽宁省警犬犬瘟热犬细小病毒和犬冠状病毒感染情况调查

犬传染病是危害养犬业健康发展的主要疾病,来自警犬方面的统计资料证实,全国每年免疫警犬的发病率为14％,其中传染病占60％以上,因传染病而死亡的犬超过死亡犬总数的80％。从近几年的临床实践和国外的有关报道来看,危害严重的犬病毒病主要有犬瘟热、犬细小病毒感染、犬传染性肝炎、犬冠状病毒病、犬副流感及狂犬病等6种疾病,     

Detection and genotyping of canine coronavirus RNA in diarrheic dogs in Japan

To clarify the prevalence of canine coronavirus (CCoV) infection in Japan, faecal samples from 109 dogs with diarrhoea were examined for CCoV RNA together with canine parvovirus type 2 (CPV-2) DNA. The detection rates of CCoV and CPV-2 for dogs aged less than 1 year were 66.3% and 43.8%, while those for dogs aged 1 year or older were 6.9% and 10.3%, respectively, which were significantly different (p < 0.0001 and p = 0.0003, respectively), indicating not CPV-2 but CCoV is an important diarrhoea-causing organism in juvenile dogs. Among the CCoV-positive dogs, 65.5% and 72.7% showed to be positive for CCoV types I and II, respectively, and simultaneous detection rate of both types was high at 40.0%. Furthermore, transmissible gastroenteritis virus (TGEV)-like CCoV RNA was detected from 8 dogs. These findings indicate that CCoV type I and TGEV-like CCoV are already circulating in Japan, though no reports have been presented to date.     

Pathogenicity of a modified-live pseudorabies vaccine virus in lambs

Subcutaneous injections of modified-live pseudorabies virus (PRV) vaccine into lambs caused clinical signs and death within 1 week after injection in 4 of 5 inoculated lambs. The clinical signs included depression, high fever, muscle fasciculations and convulsions, occasionally followed by death within 48 hours of the initial clinical signs. Histologic examinations and virus isolation procedures demonstrated PRV in the CNS of infected lambs. Sera from sick lambs remained negative for PRV antibodies. Two subsequent serial passages of the vaccine virus in lambs resulted in similar clinical signs and death in 6 of 10 inoculated lambs. Again, PRV was isolated from tissues of sick lambs, and the histopathologic findings were characteristic of the disease. Affected lambs remained seronegative to PRV, as did lambs that remained clinically normal after inoculation. There was no evidence of PRV transmission to uninoculated lambs and pigs housed with the infected lambs.     

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.     

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.     

牛冠状病毒灭活疫苗的免疫效力试验

为了评价制备的牛冠状病毒灭活疫苗的免疫效力,试验选用分离鉴定出来的牛冠状病毒(BCV-YC分离株)为制苗种毒,接种HRT-18细胞进行增殖,收集上清液进行超速离心浓缩,最后加入甲醛灭活制成油乳剂灭活疫苗,分别接种小鼠和妊娠母牛。结果表明,疫苗不仅使小鼠具有一定的保护力,而且使妊娠母牛也能产生较高的抗体水平,犊牛攻毒试验证明,产生的母源抗体能使初生犊牛抵抗牛冠状病毒的攻击。说明制备的牛冠状病毒灭活疫苗对抵抗牛冠状病毒感染具有良好的保护性。     

Fatal outbreaks in dogs associated with pantropic canine coronavirus in France and Belgium

Infection with pantropic canine coronavirus was detected during outbreaks in France and Belgium. This was concurrent in most cases with canine parvovirus 2c. One outbreak was a deadly acute systemic disease with a single pantropic canine coronavirus infection. This is the first report of a fatality associated with pantropic canine coronavirus alone outside Italy.     

Prevalence of canine enteric coronavirus in a cross-sectional survey of dogs presenting at veterinary practices

In order to determine the prevalence of canine enteric coronavirus (CECoV) in the general dog population, faecal samples were obtained in a cross-sectional study of 249 dogs presenting for any reason at veterinary practices randomly selected from across the UK. Demographic and clinical data was obtained for each of the samples, including signalment, number of dogs in the household, reason for visiting the practice, and any recent history of diarrhoea. The samples were tested by RT-PCR for the presence of both type I and type II CECoV. Seven samples were positive (three from dogs in the same household), a prevalence of 2.8% (95% confidence intervals 1.1–5.7). Phylogenetic analysis of partial M gene sequences revealed that all seven positive samples grouped with type I CECoV, the first report of this virus in the UK. None of the positive dogs presented for gastrointestinal disease. Interestingly five of the positive dogs from three separate households were aged over 6 years, suggesting that older dogs may play an important role in the persistence of CECoV in such populations.     

Seroconversion of pigs in contact with dogs exposed to canine coronavirus.

In order to determine if canine coronavirus (CCV) could be transmitted to pigs, two dogs were inoculated orally with virulent CCV. After 24 h, the dogs were moved to an isolation room that contained three three-day-old pigs. A wire mesh fence, allowing close contact between the animals, separated the dogs from the pigs. The dogs and pigs were observed for 14 days for clinical signs of disease. Samples of blood were obtained from dogs and pigs immediately before the dogs were inoculated with virus and 14 and 28 days later. The dogs developed mild clinical signs of an infection, but the pigs remained normal throughout the observation period. The dogs shed CCV for eight days after exposure. All three pigs developed neutralizing antibodies against CCV and transmissible gastroenteritis virus by 14 days after they were exposed to the dogs.