Immunization of pups with maternally derived antibodies to canine parvovirus (CPV) using a modified-live variant (CPV-2b)

The results of vaccination trials carried out on pups with maternally derived antibodies (MDA) to canine parvovirus (CPV), using a modified-live CPV-2b variant vaccine (29-97/40 strain), are reported. The vaccine was able to overcome the obstacle of MDA, and to elicit protective immunity in 100% of the pups whose antibody titres were 1:10-1:40, 83% of the pups with titres of 1:80, 57% of the pups with titres of 1:160, and even in 60% of the pups with antibody titres of 1:320.     

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.     

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.     

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.     

Experiments with a homologous,inactivated canine parvovirus vaccine in vaccination programmes for dogs

Summary

The significance of canine parvovirus (CPV) infections as a permanent threat to susceptible dogs, in particular pups, made the authors develop three liquid homologous inactivated adjuvant CPV vaccines that were compatible with existing canine vaccines and could he incorporated in current vaccination programmes. One vaccine (Kavak Parvo) contained only the CPV component, the second product (Kavak i‐LP) also contained two inactivated leptospiral antigens, and the third vaccine (Kavak i‐HLP) contained in addition an inactivated canine hepatitis virus.

This paper reports on the studies conducted to test the safety and efficacy of the three products. They were used as such and as diluents for freeze dried vaccines containing live attenuated measles, distemper, and hepatitis viruses. The study was performed in a breeding kennel where all dogs were free from CPV antibodies and the nonvaccinated sentinels remained so for the course of the study. All vaccines proved to be safe in dogs of all ages, including pregnant bitches. The efficacy of the CPV component was studied both by monitoring antibody titres for more than a year and by challenge exposure of some dogs to virulent CPV. The results obtained from these studies prove that the CPV component used in the three vaccines can be incorporated as indicated in the recommended canine vaccination programmes. The observations that both the inactivated CPV and hepatitis components do induce an active immunity in pups that are still protected by low levels of maternally derived antibodies against these viruses, make those vaccines very suitable in breeding kennels. Additional studies on a comparative basis are being continued in endemically CPV infected breeding kennels to quantify the significance of these observations in these special conditions.     

Active use of coyotes (Canis latrans) to detect Bovine Tuberculosis in northeastern Michigan, USA

Seroconversion after early vaccination at four weeks against canine parvovirus (CPV) using a high antigen titre vaccine was evaluated in 121 puppies from three breeds of dogs housed in kennels representative of the private practitioner's environment. The trial included 52 German shepherd pups, 25 Rottweiler pups and 44 Boerboel pups. From each group 11, 4, and 18 puppies acted as control dogs, respectively. Depending on the different groups, puppies were vaccinated at 4, 6, 9 and 12 weeks. The experimental group differed from the control group in that they received the high titre vaccine at 4 weeks of age, whereas the control group was not vaccinated at 4 weeks. Blood was collected from all pups prior to vaccination to measure maternally derived colostral antibody. The results indicated that vaccination at 4 weeks of age in pups with high maternally derived antibody levels, results in seroconversion rates that may lead to a reduction in the window of susceptibility with respect to CPV infection. The implications of the findings with respect to dogs in heavily contaminated environments are discussed.     

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.     

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.     

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.     

FC‐16 Clinical and immunological effects of Newcastle disease virus vaccine on bovine papillomatosis

Newcastle disease virus (NDV) has antineoplastic and immunostimulatory properties, and it is currently being clinically tested in anticancer therapy. In order to analyse the immunostimulatory effects of NDV on bovine papillomatosis, we inoculated 14 cows subcutaneously with an attenuated vaccine containing the LaSota strain of NDV (LS‐NDV). Four cows with papillomatosis served as controls. Serum samples were collected from each animal 1 h preinoculation and 7 and 21 days postinoculation. In inoculated cows on days 7 and 21, the mean antibody titres were log₂ 2.43 ± 0.92 and 5.57 ± 0.72, respectively, by haemagglutination inhibition, and the mean levels of TNFα were 5.80 ± 4.19 and 5.39 ± 2.66 ng/mL, respectively, by WEHI‐164 cytotoxicity assay. Significant differences between inoculated and control animals were evident for antibody titres on day 21 and clinical scores on day 60. A correlation was evident between the TNFα activities and clinical scores on day 21. The clinical observations at day 60 showed that the papillomas in five cows had completely resolved (36%), one animal had no alterations on clinical appearance of the tumour (7%), and papillomas in eight cows had regressed (57%). In conclusion, these results demonstrated that inoculation of LS‐NDV vaccine stimulates an antibody response and a limited increase in TNFα activity and may enhance clinical recovery in bovine papillomatosis. Funding: Scientific Research Council of Akdeniz University.     

Prevalence of positive antibody test results for canine parvovirus (CPV) and canine distemper virus (CDV) and response to modified live vaccination against CPV and CDV in dogs entering animal shelters

Canine parvovirus (CPV) and canine distemper virus (CDV) infections are relatively common in animal shelters and are important population management issues since the immune status of incoming dogs is usually unknown. This study aimed to determine the prevalence of positive antibody test results for CPV and CDV in incoming dogs aged ≥ 4 months and to measure antibody response over 2 weeks following vaccination with a modified live vaccine (MLV). Dogs aged 4-24 months entering an adoption-guarantee shelter (Shelter 1, n=51) and aged ≥ 4 months entering a limited admission shelter (Shelter 2; n=51) were enrolled. Dogs from Shelter 1 had been vaccinated with MLV at a municipal shelter 5 days before enrollment, whereas dogs from Shelter 2 had no known history of vaccination at enrollment. Sera were obtained on day 1, immediately prior to CPV/CDV MLV, and tested using an in-clinic ELISA kit to detect CPV/CDV antibodies. Dogs negative for CPV and/or CDV were retested at day 6-8 and those dogs still negative at day 6-8 were retested at day 13-15. Prior to CPV/CDV MLV on day 1, more dogs tested positive for CPV (Shelter 1 - 68.6%; Shelter 2 - 84.3%) than for CDV (Shelter 1 - 37.3%; Shelter 2 - 41.2%). On day 1, prior to MLV, all spayed/neutered animals tested CPV antibody-positive (n=17/102) and CPV antibody-positive dogs were older than serologically negative dogs (Shelter 1, P=0.0029; Shelter 2, P=0.0042). By day 13-15, almost all dogs were CPV antibody-positive (Shelter 1 - 97.9%; Shelter 2 - 100.0%) and CDV antibody-positive (Shelter 1 - 93.8%; Shelter 2 - 97.8%). MLV induces protective antibody titers against CPV/CDV in almost all dogs after 13-15 days.     

Canine parvovirus type 2c identified from an outbreak of severe gastroenteritis in a litter in Sweden

A litter of recently-vaccinated puppies in Sweden experienced signs of severe haemorrhagic gastroenteritis. Canine parvovirus (CPV) was suspected as the cause of this outbreak on the basis of the clinical signs and the presence of parvoviral antigen in the faeces from one of the affected pups - confirmed using a commercial in-clinic faecal antigen ELISA test kit. A concern was raised about whether the vaccine (which contained a live, attenuated strain of CPV) could have caused the disease and so further faecal samples from the affected pups were submitted for laboratory virus isolation and identification.On cell culture, two out of four faecal samples were found to be virus-positive. This was confirmed as being canine parvovirus by immuno-staining with CPV specific monoclonal antibody. The virus was then tested using a series of PCR probes designed to confirm the identity of CPV and to distinguish the unique vaccine strain from field virus. This confirmed that the virus was indeed CPV but that it was not vaccine strain. The virus was then typed by sequencing the 426 amino acid region of the capsid gene which revealed this to be a type 2c virus.Since its emergence in the late 1970s, canine parvovirus 2 (CPV2) has spread worldwide and is recognised as an important canine pathogen in all countries. The original CPV2 rapidly evolved into two antigenic variants, CPV2a and CPV2b, which progressively replaced the original CPV2. More recently a new antigenic variant, CPV2c, has appeared. To date this variant has been identified in many countries worldwide but there have been no reports yet of its presence in any Scandinavian countries. This case report therefore represents the first published evidence of the involvement of CPV2c in a severe outbreak of typical haemorrhagic gastroenteritis in a susceptible litter of pups in Scandinavia.     

Serological responses of adult dogs to revaccination against distemper, parvovirus and rabies

Serum antibody titres to canine distemper virus (CDV), canine parvovirus (CPV) and rabies were measured in dogs that had not been revaccinated annually and compared with the titres in a control group of regularly vaccinated animals; 83 per cent (171 of 207) of the dogs vaccinated against CDV one or more years earlier had serum neutralising antibody titres equal to or greater than 16; 64 per cent (136 of 213) of the dogs vaccinated against CPV one or more years earlier had haemagglutination inhibiting titres equal to or greater than 80; and 59 per cent (46 of 78) of the dogs vaccinated against rabies two or more years earlier had serum neutralising antibody titres equal to or greater than 0.5 iu/ml. Three weeks after a single booster vaccination the dogs' antibody titres against CDV had increased above the threshold level in 94 per cent of the dogs, against CPV in 68 per cent, and against rabies in 100 per cent.     

Three-year rabies duration of immunity in dogs following vaccination with a core combination vaccine against canine distemper virus, canine adenovirus type-1, canine parvovirus, and rabies virus

Thirty-two seronegative pups were vaccinated at 8 weeks of age with modified-live canine distemper virus (CDV), canine adenovirus type-2 (CAV-2), and canine parvovirus (CPV) vaccine and at 12 weeks with a modified-live CDV, CAV-2, CPV, and killed rabies virus vaccine. An additional 31 seronegative pups served as age-matched, nonvaccinated controls. All test dogs were strictly isolated for 3 years after receiving the second vaccination and then were challenged with virulent rabies virus. Clinical signs of rabies were prevented in 28 (88%) of the 32 vaccinated dogs. In contrast, 97% (30 of 31) of the control dogs died of rabies infection. These study results indicated that no immunogenic interference occurred between the modified-live vaccine components and the killed rabies virus component. Furthermore, these results indicated that the rabies component in the test vaccine provided protection against virulent rabies challenge in dogs 12 weeks of age or older for a minimum of 3 years following vaccination.     

Immunization effectiveness of the inactivated vaccine against infectious bovine rhinotracheitis (IBR) with an oily adjuvant]

The adjuvant vaccine against infectious bovine rhinotracheitis (IBR) was tested as to its innocuousness and immunogenicity. The immunity response induced by a single or double application of different vaccine doses was evaluated according to the content of neutralization antibodies (NP) in the blood serum. A direct dependence was revealed between the size of the inoculum and NP content in the blood serum, with NP titres of 1 : 9.3; 1 : 26.6, 1 : 80 and 1 : 149 after doubled application of 1, 2, 5, and 10 ml of the vaccine. The calves inoculated at an age of one week produced antibodies in the same titres as one- to five-month-old calves. Singly inoculated animals mostly showed zero-level or low antibody titres, but revaccination induced general serum-positivity with NP titres 1 : 4 to 1 : 128. The animals which had been in contact with the IBR virus and were serologically negative during inoculation or had an NP content in the blood serum at a titre of 1 : 4 or less, gave an anamnestic response to inoculation, but revaccination did not lead to a significant rise in antibody content. Double administration of 2 ml of vaccine in four production charges induced the production of antibodies with average titres of 1 : 36, 1 : 25; 1 : 31 and 1 : 24. Inoculation of susceptible animals in non-infected herds and of clinically healthy animals in infected herds did not cause any health disorders. IBR; inactivated adjuvant vaccine; different age; different doses; immunity response; neutralization antibodies.     

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.     

DNA Immunization Against Very Virulent Infectious Bursal Disease Virus with VP2‐4‐3 Gene and Chicken IL‐6 Gene

The present study was to investigate the feasibility and efficiency of the DNA vaccine to protect chickens against very virulent infectious bursal disease virus (vvIBDV) infection. A plasmid DNA carrying VP2‐4‐3 genes of vvIBDV SH95 and a plasmid DNA carrying chicken interleukin‐6 (ChIL‐6) genes were constructed and designated as pALTER‐MAX‐VP2‐4‐3 and pALTER‐MAX‐ChIL‐6 respectively. Several DNA vaccination experiments were performed: 1‐week‐old chickens were intramuscularly injected with only plasmid pcDNA3‐VP2, pALTER‐MAX‐VP2‐4‐3 or mixture with pALTER‐MAX‐ChIL‐6. The chickens at 4 weeks old were orally inoculated with vvIBDV SH95. The results showed that immunization with the mixture of pALTER‐MAX‐VP2‐4‐3 and pALTER‐MAX‐ChIL‐6 three times conferred protection for 90% of chickens. Enzyme‐linked immunosorbent assay (ELISA) antibody titres in chickens immunized together with pALTER‐MAX‐ChIL‐6 were higher than those immunized simply with plasmid pcDNA3‐VP2 or pALTER‐MAX‐VP2‐4‐3. IBDV was not detected in the bursa of the protected chickens at 8 days after challenge by RT‐PCR. The results indicate that protection against vvIBDV can be achieved by using the VP2‐4‐3 gene of vvIBDV as a DNA vaccine. Furthermore, the simultaneous injection of ChIL‐6 plasmid significantly increased the protection after challenge with the very virulent strain.     

Prevalence of antibodies to four major canine viral diseases in dogs in a Liverpool hospital population

To determine the prevalence of antibodies to four major canine viruses, serum samples were obtained from 190 dogs presented to the Small Animal Hospital at the University of Liverpool. Antibodies to canine coronavirus (CCV), canine distemper virus (CDV), canine parvovirus (CPV) and rotavirus (RV) were assayed using serum neutralisation (CCV and CDV), haemagglutina-tion inhibition (CPV) and indirect fluorescent antibody (RV) techniques. Overall 54 per cent of dogs were seropositive to CCV, 84 per cent to CDV, 70 per cent to CPV and 86 per cent to RV, The antibody titres obtained were analysed with respect to a number of different parameters including: age, sex, breed, vaccination status, exercise regime, diet, Liverpool district in which the dog resided and the presence of diarrhoea, The prevalence and titres of antibodies to CCV, CDV and RV appeared to be influenced by age, CDV by vaccination status, and CCV by the presence of diarrhoea; no other influencing parameters were found.     

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)     

Serosurvey of ex situ giant pandas (Ailuropoda melanoleuca) and red pandas (Ailurus fulgens) in China with implications for species conservation.

Conservation strategies for the giant panda (Ailuropoda melanoleuca) include the development of a self-sustaining ex situ population. This study examined the potential significance of infectious pathogens in giant pandas ex situ. Serologic antibody titers against canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus (CAV), canine coronavirus (CCV), canine herpesvirus, canine parainfluenza virus (CPIV), Toxoplasma gondii, Neospora caninum, and Leptospira interrogans were measured in 44 samples taken from 19 giant pandas between 1998 and 2003 at the Chengdu Research Base of Giant Panda Breeding in Sichuan, China. Seroassays also included samples obtained in 2003 from eight red pandas (Ailurus fulgens) housed at the same institution. All individuals had been vaccinated with a Chinese canine vaccine that included modified live CDV, CPV, CAV, CCV, and CPIV. Positive antibody titers were found only against CDV, CPV, and T. gondii. Sera were negative for antibodies against the other six pathogens. Results indicate that the quality of the vaccine may not be reliable and that it should not be considered protective or safe in giant pandas and red pandas. Positive antibody titers against T. gondii were found in seven of the 19 giant pandas. The clinical, subclinical, or epidemiologic significance of infection with these pathogens via natural exposure or from modified live vaccines in giant pandas is unknown. Research in this area is imperative to sustaining a viable population of giant pandas and other endangered species.