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.     

Contact rates between wild and domestic canids: no evidence of parvovirus or canine distemper virus in crab-eating foxes

Evaluating the risk of disease spill-over from domestic dogs to wildlife depends on knowledge of inter-specific contact rates and/or exposure to aetiological agents in dog environments. Here, contact rates of crab-eating foxes (Cerdocyon thous) with sympatric domestic dog populations were measured over 25months in Amazon Brazil. Foxes and dogs were serologically and clinically monitored for exposure to canine parvovirus (CPV-2) and canine distemper virus (CDV), pathogens known to have caused wildlife population declines elsewhere. Twenty-two of 24 (92%) tagged foxes visited one or more houses in a median 2 (range 1-3) villages per night where dog densities ranged from 7.2 to 15.4 per km(2) (mean 9.5 per km(2)). Foxes spent an average 6.4% (0-40.3%) of their 10h nocturnal activity period in villages, the equivalent of 38m (range 0-242) per night. The rate of potential exposure to disease agents was thus high, though varied by 3 orders of magnitude for individual foxes. Overall, 46% of the fox population was responsible for 80% of all contacts. None of the 37 monitored foxes however showed serological or clinical evidence of infection with CPV-2 or CDV. Seroprevalences for CPV-2 and CDV antibodies in the local domestic dog population were 13% (3/23) and 9% (2/23), respectively, and 89% of 97 monitored pups born during the study presented clinical signs consistent with active CPV-2 infection (haemorrhagic diarrhoea, vomiting, rapid morbidity and emaciation). Although there was no evidence for infection with either virus in foxes, the high level of contact of foxes with peridomestic habitats suggests that the probability of potential spill-over infections from dogs to foxes is high.     

Characterization of monoclonal antibodies directed against the canine distemper virus nucleocapsid protein

We have established four monoclonal antibodies (MAbs) against the nucleocapsid protein (NP) of canine distemper virus (CDV). A competitive binding assay has revealed that the MAbs are directed against two antigenic domains. An immunofluorescence assay using a series of deletion clones of the NP and an immunoprecipitation assay using the NP have revealed that two of the MAbs recognize the C-terminal region of the NP while the other two recognize the tertiary structure of the N-terminal domain. These MAbs reacted with all eight strains of CDV used in this study, but showed different reactivities against measles virus and rinderpest virus.     

犬瘟热与犬细小病毒混合感染的诊断与治疗

犬瘟热病毒与犬细小病毒分别引致犬瘟热和犬细小病毒病。这两种病毒对犬科动物危害大,发病率和死亡率都较高,且混合感染较为常见。通过临床诊断、血清学检测、血常规检测、影像学检查等方法,分析一例犬瘟热和犬细小病毒混合感染病例,并采用特异性血清与支持对症治疗相结合方法,提出综合防治措施。通过对该典型案例的深入分析,可为临床同类疾病诊断和治疗提供参考。     

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.     

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.     

抗犬瘟热病毒重组核衣壳蛋白单克隆抗体的制备及鉴定

以纯化的重组犬瘟热病毒(CDV)N蛋白免疫BALB/c小鼠,应用常规杂交瘤技术获得两株能稳定分泌特异性单克隆抗体的杂交瘤细胞系,分别命名为A_4C_6C_(12)和A_5B_8H_7。间接ELISA检测腹水效价分别为1:10~6、1:10~5;亚类鉴定结果分别为IgG2a、IgG2b,轻链均为κ型;Western blot和ELISA分析结果显示2株单克隆抗体均能与重组N蛋白和CDV发生反应,而与犬细小病毒及犬腺病毒等无交叉反应;ELISA叠加试验的增值结果表明两株单克隆抗体识别的抗原位点不同。特异性抗CDV-rN的单克隆抗体的获得,为进一步用于临床诊断研究奠定了基础。     

犬瘟热病毒单克隆抗体夹心ELISA检测方法的建立

为建立方便快捷的犬瘟热病毒(CDV)检测方法,本实验应用杂交瘤细胞融合技术,建立了4株分泌抗CDV单克隆抗体(MAb)的杂交瘤细胞株,分别命名为A2、F7、H4和G12.相加ELISA试验显示4株MAb作用于CDV不同的抗原表位.选取相加指数较高的两株MAb G12和A2分别作为捕获抗体和酶标检测抗体,建立检测CDV的夹心ELISA检测方法,并对实验条件进行了优化.结果显示,该方法与犬细小病毒、犬副流感病毒、犬腺病毒1型、犬冠状病毒等犬类病毒无交叉反应,敏感度为5 μg/mL,变异系数小于6％.利用该方法与RT-PCR方法同时检测57份临床样品,两种方法的符合率为100％.本实验建立的MAb夹心ELISA方法具有特异、敏感、方便快捷等优点,适用于大批量临床样品检测.     

同时检测犬瘟热病毒和犬细小病毒双重PCR方法的建立

为建立可以同时检测犬瘟热病毒(CDV)和犬细小病毒(CPV)的双重PCR方法,本研究根据GenBank登录的CDV N蛋白序列和CPV NS基因保守序列,设计合成2对特异性引物。通过优化反应条件,对CDV阳性病毒株反转录后的cDNA模板和CPV的DNA模板进行双重PCR扩增,同时得到2条与试验设计相符的669 bp(CDV)和392 bp(CPV)特异性条带,建立了同时检测CDV和CPV的双重PCR方法。实验结果表明:在同一PCR反应体系中可以同时检测这2种病毒,而对犬腺病毒Ⅰ型、犬腺病毒Ⅱ型、狂犬病毒检测均为阴性;CDV和CPV的最低检出限分别为101.8TCID50和101.4TCID50。采用该方法对在黑龙江省不同地区所采集的30份犬病料样品进行检测,CDV阳性率为30%;CPV阳性率为23.33%,表明建立的PCR方法可以用于临床诊断。     

抗犬细小病毒单克隆抗体的制备及初步应用

犬细小病毒 ( Canine Parvirus,CPV)感染是近年来发现的犬的一种烈性传染病 ,可引起犬出血性肠炎和心肌炎 ,并使白细胞大量死亡 ,在幼犬中的发病率和死亡率均很高 ,目前已成为犬的一种重要传染病 ,我国亦有本病的暴发流行 ,并已分离出多株病毒 ,研究报道日趋增多。目前该病还没有好的治疗方法 ,只有高价免疫球蛋白在发病早期具有较好效果。为此 ,我们制备了该病毒的单克隆抗体 ( Monoclonal antibody,Mc Ab) ,从建立的 3株 CPV Mc Ab细胞株中筛选得到了 1株只有中和活性的特异的抗 CPV Mc Ab细胞株 ,并应用于治疗中早期 CPV感染犬…     

Antibodies against canine parvovirus in wolves of Minnesota: a serologic study from 1975 through 1985

Serum samples (n = 137) from 47 wild wolves (Canis lupus; 21 pups and 26 adults) were evaluated from 1975 to 1985 for antibodies against canine parvovirus, using the hemagglutination inhibition (HI) test. In addition, several blood samples (n = 35) from 14 of these wolves (6 pups and 8 adults) were evaluated simultaneously for erythrocyte and leukocyte counts, and for hemoglobin and blood urea nitrogen concentrations. Sixty-nine (50%) of the serum samples (35 wolves) had HI titers of greater than or equal to 256, whereas 68 (50%) of the samples (16 wolves) had HI titers of less than or equal to 128. Significant differences in the geometric mean titers were not found between pups and adults or between males and females. Of the 47 wolves evaluated, 12 (25%) developed a greater than or equal to fourfold increase in antibody titers during the 11-year period, with 2 wolves developing serologic conversions in 1976. The data indicate that canine parvovirus may have begun infecting wolves before or at the same time that it began infecting the dog population in the United States.     

Epizootic canine distemper virus infection among wild mammals

In the spring of 2007, seven raccoon dogs and a weasel were captured near the city of Tanabe in Wakayama prefecture, Japan. The causative agent of the animals' death 1-2 days after capture was identified as canine distemper virus (CDV) by virus isolation, immunostaining with an anti-CDV polyclonal antibody, and a commercially available CDV antigen-detection kit. Sequence analysis of hemagglutinin genes indicated the isolated viruses belong to genotype Asia-1 and possess the substitution from tyrosine (Y) to histidine (H) at position 549 that is associated with the spread of CDV to non-canine hosts. A serosurvey for CDV was then conducted among wild animals in the region. The animals assayed consisted of 104 raccoons, 41 wild boars, 19 raccoon dogs, five Sika deer, two badgers, one weasel, one marten, one Siberian weasel and one fox. Virus-neutralization (VN) tests showed that, except for fox and weasel, all of the species assayed had VN antibodies to CDV. Interestingly, 11 of the 41 wild boars (27%) and two of the five Sika deer assayed possessed VN antibodies to CDV. These findings indicate that CDV infection was widespread among wild mammals during this epizootic.     

Seroconversion of puppies to canine parvovirus and canine distemper virus: a comparison of two combination vaccines

Sixty puppies were randomly assigned to receive one of two commercially available combination vaccines, and responses to the canine parvovirus and canine distemper virus components of the vaccines were determined by measuring serum antibody titers. The percentage of puppies that seroconverted to canine parvovirus was significantly higher and the mean time for seroconversion was significantly shorter for puppies that received one of the vaccines than for puppies that received the other vaccine. Percentages of puppies that seroconverted to canine distemper virus were not significantly different.     

Presence of antibodies to canine distemper virus, canine parvovirus and canine adenovirus type 1 in free-ranging jackals (Canis adustus and Canis mesomelas) in Zimbabwe

A survey of free-ranging jackals (Canis adustus and Canis mesomelas) in Zimbabwe was conducted to determine the prevalence of serum antibodies to canine distemper virus (CDV), canine parvovirus (CPV) and canine adenovirus type 1 (CAV-1). Sera from 16 Canis adustus and 22 Canis mesomelas were collected from 1990 to 1993 from various regions of Zimbabwe and assayed by means of immunofluorescent techniques. Seroprevalence in C. adustus and C. mesomelas respectively were 50% and 63.6% for CDV, 12.5% and 18.2% for CPV and 37.5 and 9.1 for CAV-1. These results demonstrate that jackals are infected with these viruses and may act as reservoirs of them, although their susceptibility to the viruses is not known.     

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.