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.     

Rapid enzyme-linked immunosorbent assay for detecting antibodies to canine parvovirus

A rapid screening assay for determining antibodies to canine parvovirus in dog serum using monoclonal antibodies and enzyme-linked immunosorbent assay (ELISA) technology was developed. The ELISA could be read visually, and the results correlated well with serum neutralization (SN) and hemagglutination inhibition (HI) titers. Sera with SN less than or equal to 1:4 or HI less than or equal to 1:10 had an 87.9% correlation with ELISA and sera with SN greater than or equal to 1:64 or HI greater than or equal to 1:80 had a 94.4% correlation. The assay took only 10 to 15 minutes to perform and did not require specialized equipment. The ELISA should be useful in monitoring dogs for the presence of maternal antibodies against parvovirus and for determining seroconversion after vaccination.     

A modified live canine parvovirus vaccine. II. Immune response

The safety and efficacy of an attenuated canine parvovirus (A-CPV) vaccine was evaluated in both experimental and in field dogs. After parenteral vaccination, seronegative dogs developed hemagglutination-inhibition (HI) antibody titers as early as postvaccination (PV) day 2. Maximal titers occurred within 1 week. Immunity was associated with the persistence of HI antibody titers (titers greater than 80) that endured at least 2 years. Immune dogs challenged with virulent CPV did not shed virus in their feces. The A-CPV vaccine did not cause illness alone or in combination with living canine distemper (CD) and canine adenovirus type-2 (CAV-2) vaccines, nor did it interfere with the immune response to the other viruses. A high rate (greater than 98%) of immunity was engendered in seronegative pups. In contrast, maternal antibody interfered with the active immune response to the A-CPV. More than 95% of the dogs with HI titers less than 10 responded to the vaccine, but only 50% responded when titers were approximately 20. No animal with a titer greater than 80 at the time of vaccination became actively immunized. Susceptibility to virulent CPV during that period when maternal antibody no longer protects against infection, but still prevents active immunization, is the principal cause of vaccinal failure in breeding kennels where CPV is present. Reduction, but not complete elimination, of CPV disease in large breeding kennels occurred within 1-2 months of instituting an A-CPV vaccination program.     

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.     

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.     

Stray dogs as sentinels for canine parvovirus

An attempt to determine the prevalence of canine parvovirus in the stray dog population of Franklin County, Ohio (U.S.A.) was made by sampling dogs during the first 6 months of 1981. Serum and fecal samples, which were collected from 209 strays at time of euthanasia, were tested by serum hemagglutination inhibition (HI) and fecal hemagglutination (HA) techniques to determine canine parvovirus experience (seropositive) or fecal virus shedding, respectively. Sera collected from 93 strays for an unrelated study conducted in 1979 were used as the comparison group. All of the 1979 sera were HI negative (< 1:80) whereas, 139 of 201 (69.2%) sera suitable for testing from the 1981 group of strays were HI positive (? 1:80). The fecal HA results from the 1981 group revealed 26 of the 209 (12.4%) dogs were shedding parvovirus at time of euthanasia (HA titers ? 1:64). Of these 26 of the 209 (12.4%) dogs were shedding parvovirus at time of euthanasia were found to be seropositive. These results indicate that the stray population of Franklin County, Ohio, was not exposed in 1979, but by 1981 had experienced and for the most part, had recovered from canine parvovirus as indicated by a 69.2% seropositive dog population with 12.4% active virus shedders. The stray dog population, if sampled regularly, could thus serve as a sentinel for canine parvovirus activity in a community.     

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)     

Antibody levels and protection to canine parvovirus type 2

The relationship between maternally derived antibody (MDA) levels and protection to canine parvovirus (CPV) infection in pups is reported. Twelve pups with a wide range of haemagglutination inhibiting (HI) titres of MDA to CPV were divided into four groups, with each group balanced for antibody titres. The dogs were inoculated with a field CPV-2b strain and clinical signs, virus shedding and antibody response were assessed. The CPV was not detected in the faeces of dogs with HI titres of 320 at any time. In dogs with HI titres up to 160, active CPV replication after challenge was demonstrated by real-time polymerase chain reaction. The successful infection of dogs with HI titres of 80 and 160 was confirmed by seroconversion, evaluated at day 14 post-infection. These findings demonstrated that CPV infection could also occur in the presence of MDA HI titres (> or =80) usually considered fully protective.     

The effect of staphylococcal antigen on the output of cells from the popliteal lymph node of immunized sheep

Serum samples collected from dogs routinely presented at a clinic between June 1974 and October 1980 were tested for the presence of haemagglutination inhibition (HI) titres to canine parvovirus. The first positive titre (> 1:320) was demonstrated in serum collected in October 1979. The first confirmed clinical case of canine parvovirus enteritis was diagnosed by the authors in July 1979.

In addition, between 1st December 1980 and 1st March 1981, serum samples were collected from 106 healthy dogs which were presented for canine parvovirus vaccination for the first time. Twenty-four dogs (approx. 23%) showed HI titres > 1:320 indicating probable previous canine parvovirus infection. Therefore approx. 80% of dogs in the clinic area were at risk at that time and vaccination should have protected them from infection.     

Evaluation of different methods of inactivation of Newcastle disease virus and avian influenza virus in egg fluids and serum

Viruses conveyed in shipments of eggs, viral diagnostic reagents, or avian serum samples are a potential hazard for susceptible poultry. Different methods of treatment of those materials to eliminate the hazard of virulent and avirulent strains of Newcastle disease virus (NDV) or avian influenza virus (AIV) were evaluated. The NDV strains tested were more thermostable than the AIV strains. The results suggest that standard pasteurization methods would not reliably inactivate the concentrations of NDV used. beta-Propiolactone (BPL) (greater than or equal to 0.025%) inactivated NDV or AIV in allantoic fluid, but higher concentrations were needed to inactivate virus diluted in serum. Hemagglutination (HA) of NDV and AIV and hemolysis (HL) activity of NDV were reduced or eliminated by 0.4% BPL. Formalin (greater than or equal to 0.04%) inactivated either virus but adversely affected HA and HL activity. NDV or AIV was inactivated by binary ethylenimine (BEI) (0.01 M) with no adverse effect on HA or HL. Heat (56 C) or BEI (0.01 M) had no apparent effect on hemagglutination-inhibition (HI) titers of NDV and AIV antisera, the effect of formalin (0.1%) was variable, and BPL (greater than or equal to 0.25%) depressed the HI titers of both antisera. The optimum method should achieve virus inactivation without harming the treated material.     

A longitudinal serological survey of parvovirus infection in dogs

Serum samples collected from dogs routinely presented at a clinic between June 1974 and October 1980 were tested for the presence of haemagglutination inhibition (HI) titres to canine parvovirus. The first positive titre (>1:320) was demonstrated in serum collected in October 1979. The first confirmed clinical case of canine parvovirus enteritis was diagnosed by the authors in July 1979. In addition, between 1st December 1980 and 1st March 1981, serum samples were collected from 106 healthy dogs which were presented for canine parvovirus vaccination for the first time. Twenty-four dogs (approx. 23%) showed HI titres >1:320 indicating probable previous canine parvovirus infection. Therefore approx. 80% of dogs in the clinic area were at risk at that time and vaccination should have protected them from infection.     

Clinical and pathologic features of parvoviral diarrhea in pound-source dogs

From June 1980 through May 1982, 161 pound-source dogs that developed diarrhea while being used in research were evaluated to determine whether canine parvovirus (CPV) type 2 was the etiologic agent. Evaluation included notation of clinical signs, determination of serum CPV-specific immunoglobulin (Ig) M and IgG titers, virus isolation attempts, and histologic examination of tissues. Criteria for diagnosis of canine parvoviral enteritis were serum CPV-specific IgM antibodies, isolation of CPV from feces, and histologic evidence of intestinal crypt cell necrosis. Upon arrival, 67 clinically normal pound-source dogs were evaluated to determine the prevalence of fecal shedding of CPV and to determine their antibody titers to CPV. Parvovirus was not isolated from any of these dogs, although 76% had IgG antibodies and 3% had IgM antibodies. Of the 161 dogs with diarrhea, 40 (25%) had parvoviral enteritis. Of dogs with parvoviral enteritis, 71% had IgG antibodies and 68% had IgM antibodies. Canine parvovirus was isolated from 18 dogs. Serum IgG antibodies were found in 85% of dogs with diarrhea due to other causes. The geometric mean titer of IgG antibodies to CPV was not significantly different among the 3 groups. Clinical signs that appeared significantly (P less than 0.05) more often in dogs with parvoviral enteritis included bloody diarrhea, anorexia, fever (greater than or equal to 39.4 C), and leukopenia (WBC less than 6,000/mm3). Cases occurred throughout the year, without apparent seasonal variation. The duration between arrival and onset of diarrhea was significantly (P less than 0.05) shorter for dogs with parvoviral enteritis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serological profiles of commercial broiler breeders and their progeny. 2. Newcastle disease virus

Newcastle disease virus (NDV) hemagglutination-inhibition (HI) titers were determined for serum samples from eight commercial broiler breeder flocks and their progeny. The chickens sampled had been vaccinated and reared by different producers in different regions of the United States. Breeder flocks had the highest number of NDV-positive HI titers (greater than or equal to 1:10). Eighty percent or more of the samples from six of eight breeder flocks were positive; the geometric mean titers (GMTs) for those six breeder flocks ranged from 19 to 92. Only 3 of 8 broiler flocks had an increased frequency of positive titers and higher GMTs after vaccination. The frequency of positive titers was greater than 80% in only 2 of 8 of the oldest broiler flocks. The number of NDV-negative titers (less than 1:10) increased with age in most broiler flocks, even though all had been vaccinated once or more with live NDV vaccines.     

Canine distemper virus in coyotes: a serologic survey

Serum samples from 228 coyotes were selected randomly from a serum bank assembled from Texas from 1975 to 1984 and were evaluated serologically for neutralizing antibodies against canine distemper virus (CDV). One hundred and twenty-eight (56%) of the 228 coyotes had antibody titers of greater than or equal to 1:5 against CDV (seropositive). The serologic prevalence (seroprevalence) of antibodies against CDV infection was higher in the spring (62%) than in the fall (40%). The seroprevalence of CDV in various age groups was different; 25 of 101 coyotes (25%) were seropositive at less than 1 year of age, 35 of 52 (67%) were positive between 1 and 2 years of age, and 68 of 75 (91%) were positive at greater than or equal to 2 years of age. The results indicated that CDV was enzootic in coyote populations of southern Texas, with an increasing number of seropositive coyotes noted annually. The sex of the coyote did not appear to be related to the seroprevalence against CDV.     

Immune response of the llama (Lama glama) to tetanus toxoid vaccination

An ELISA was developed to measure serum concentrations of tetanus toxoid-specific immunoglobulins. The titers obtained with this assay were compatible with those obtained by the standard mouse toxin-neutralization test. Serum samples from 123 llamas were analyzed for ELISA titers to tetanus toxoid. Of the 82 vaccinated adults, 75 (91%) had titers greater than or equal to 1:50. The vaccination status and titers of weanlings and juveniles (3 to 12 months old) varied; of the 21 vaccinated, 17 (81%) had titers greater than or equal to 1:50 and 7 of 9 (78%) unvaccinated llamas had titers less than 1:50. The ELISA titers of unvaccinated llamas less than 8 weeks old (crias) were matched with the maternal titers. All crias with titers less than 1:50 had dams with titers greater than or equal to 1:50.     

Viral antibody studies of laboratory dogs with diarrheal disease

Viral antibody studies were done on laboratory dogs in an epizootic of gastrointestinal disease. Increased hemagglutination-inhibition antibody titers to a parvovirus (PV) antigenically related to feline panleukopenia virus were found in convalescent serum specimens of 78% (20/26) of the affected dogs and in 83% (5/6) of apparently healthy dogs. With one exception, all dogs tested had significant levels of hemagglutination-inhibition antibody to this PV. Similar increased antibody titers were found to feline panleukopenia virus. Also, neutralizing antibody responses were detected to the canine coronavirus in 24% (6/25) and canine herpesvirus in 45% (10/22) of the affected dogs. However, antibody titers did not increase to canine distemper virus, infectious canine hepatitis virus, canine parainfluenza virus, or minute virus of canines. Subsequent serotesting of the colony provided evidence that additional PV infections occurred in pups from each of 8 litters born 3 to 8 months after the epizootic. These findings indicated the continued presence of the PV for more than 1 year in the infected colony. Of 19 laboratory personnel who worked with the affected dogs, none, including 4 with a concurrent diarrheal disease, developed or had antibodies to the PV or canine coronavirus.     

3种犬细小病毒感染诊断方法比较

本研究应用犬细小病毒抗原快速检测试剂盒、血凝/血凝抑制试验和PCR方法对120份具有腹泻/呕吐症状的患犬粪便样本进行了犬细小病毒检测。结果显示,3种方法检测阳性份数分别为60,49,68。犬细小病毒抗原快速检测试剂盒与血凝/血凝抑制(HA/HI)试验相比较,敏感性、特异性及总符合率分别为100.0%,84.5%,90.8%;与PCR法相比较,敏感性、特异性及总符合率分别为85.3%,96.2%,90.0%。从试验结果看,HA/HI法具有较高的特异性,但敏感性较低;PCR具有高度敏感性和特异性,但不适合临床推广;细小病毒抗原快速检测试剂盒,在正确操作下结果可靠,是临床诊断犬细小病毒感染的首选方法。     

Evaluation of serologic methods for the detection of antibodies to encephalomyocarditis virus in swine fetal thoracic fluids.

Hemagglutination inhibition (HI) and agar gel immunodiffusion (AGID) tests were compared to the serum neutralization (SN) test to evaluate their ability to detect antibodies to encephalomyocarditis virus (EMCV). Swine fetal thoracic fluids of known EMCV SN antibody titers (200 samples greater than or equal to 1:2, 100 samples less than 1:2) were selected from a collection of field cases. The thoracic fluids were tested for EMCV antibodies by HI and AGID, and the results were compared to those of the SN test. Of 200 SN antibody-positive samples, 183 (91.5%) and 173 (86.5%) were positive in HI and AGID tests, respectively. Of 100 SN-negative samples, 81 (81%) and 94 (94%) were negative in HI and AGID tests, respectively. Agreement between the tests was analyzed by calculating Kappa values. The values were 0.73 between SN and HI tests and 0.77 between SN and AGID tests, indicating very good to excellent agreement for HI and AGID tests with the SN test. Of 200 SN-positive samples, 19 samples with low SN titers (1:2-1:16) were further tested by Western immunoblotting, and all were confirmed as positive. Interpretation of the present results suggests that both HI and AGID tests can be used as alternatives to the SN test.     

Clinical and virological findings in pups naturally infected by canine parvovirus type 2 Glu-426 mutant.

An outbreak of canine parvovirus type 2 infection caused by the Glu-426 mutant in 2 litters of pups is reported. The infected pups (n = 6) were monitored daily for evidence of clinical signs and hematological changes and for the evaluation of viral shedding in the feces. The disease induced by the Glu-426 mutant was mild in all the infected pups. Vomiting and hemorrhagic diarrhea were not observed; however, the pups developed mucoid diarrhea (3.5 median days), depression (1.5 median days), and relative leukopenia and lymphopenia (2.5 median days). Fever and loss of appetite were observed only in 2 pups. Virus was detected in the feces for 4.5, 6.5, and 46 median days by hemagglutination, virus isolation on cell cultures, and real-time polymerase chain reaction (PCR), respectively. By real-time PCR, the highest viral DNA titers were detected in the feces of both litters at day 10, reaching median values of more than 10(10) DNA copies/mg of feces.     

Antibody responses of guinea-pigs, rabbits and pigs to inactivated porcine parvovirus vaccines

Antibody responses were compared in guinea-pigs, rabbits and pigs following vaccination with inactivated porcine parvovirus (PPV) vaccines. Mean PPV hemagglutination inhibition (HI) antibody titers of 52, 56 and 36 at 1 week after first vaccination and 896, 640 and 512 at 2 weeks after second vaccination were detected in guinea-pigs, rabbits and pigs, respectively. PPV vaccines prepared with greater concentrations of virus, as determined by hemagglutination (HA) units, and of aluminum hydroxide gel adjuvant, induced higher HI antibody titers in guinea-pigs. Optimal concentrations for inducing consistently high antibody titers consisted of vaccine virus with a HA titer of 256/0.1 ml and gel adjuvant at a final concentration of 50%. A second vaccination at 4 weeks compared to 2 or 3 weeks after first vaccination resulted in higher mean HI titers. These data provide preliminary information on the use of guinea-pigs or rabbits as laboratory animal models for testing the potency of PPV vaccines.