A R Peters

Institute of Animal Health and Veterinary Biologicals, Bowringpet, Karnataka, India

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Publications (6)8.47 Total impact

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    ABSTRACT: Two experimental bovine respiratory syncytial virus (BRSV) challenge studies were undertaken to evaluate the efficacy of a single intranasal dose of a bivalent modified live vaccine containing BRSV in 3-week-old calves. In the first study, vaccine efficacy was evaluated in colostrum deprived (maternal antibody negative) calves 5, 10 and 21 days after vaccination. Nasal shedding of BRSV was significantly reduced in vaccinated calves challenged 10 or 21 days after vaccination. Virus excretion titres were also reduced in vaccinates challenged 5 days after vaccination but reduction in duration of shedding and total amount of virus shed were not statistically significant. Clinical disease after challenge in this study was mild. In the second study, vaccine efficacy was assessed in calves with maternal antibodies against BRSV by challenge 66 days post-vaccination. Vaccination significantly reduced nasal shedding after challenge and the severity of clinical disease was also reduced.
    The Veterinary Journal 12/2007; 174(3):627-35. · 2.17 Impact Factor
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    ABSTRACT: The efficacy of a quadrivalent vaccine against viral bovine respiratory diseases (BRD) was assessed in four experimental studies. Calves between 2 and 9 months of age were allocated to one of two treatment groups (n=9-15) and then received either the vaccine or sterile saline in two doses approximately 3 weeks apart. Three to 5 weeks after the second injection, animals were challenged experimentally with one of the viruses, bovine herpes-virus-1 (BHV-1), parainfluenza type-3 virus (PI(3)V), bovine viral-diarrhoea virus type 1 (BVDV), or bovine respiratory syncytial virus (BRSV) and were then monitored for at least 2 weeks. The administration of the vaccine was associated with enhanced antibody response to all four viruses post-challenge, with the reduction of the amount or duration (or both) of virus shedding in the BHV-1, PI(3)V, BVDV and BRSV studies and with an improvement of some clinical signs in the BHV-1 (nasal discharge, and rectal temperature) and the PI(3)V studies (abnormal respiration, and depression).
    The Veterinary Journal 12/2007; 174(3):616-26. · 2.17 Impact Factor
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    ABSTRACT: Several laboratory studies assessed the duration of immunity of a quadrivalent vaccine (Rispoval 4, Pfizer Animal Health) against bovine respiratory diseases (BRD) caused by bovine herpes-virus type-1 (BHV-1), parainfluenza type-3 virus (PI3V), bovine viral-diarrhoea virus type 1 (BVDV), or bovine respiratory syncytial virus (BRSV). Calves between 7 weeks and 6 months of age were allocated to treatment and then were injected with two doses of either the vaccine or the placebo 3 weeks apart. Six to 12 months after the second injection, animals were challenged with BHV-1 (n=16), PI3V (n=31), BVDV (n=16), or BRSV (n=20) and the course of viral infection was monitored by serological, haematological (in the BVDV study only), clinical, and virological means for > or =2 weeks. Infection induced mild clinical signs of respiratory disease and elevated rectal temperature in both vaccinated and control animals and was followed by a dramatic rise in neutralising antibodies in all treatment groups. Titres reached higher levels in vaccinated calves than in control calves after challenge with BHV-1, BVDV, or BRSV. On day 3 after PI3V challenge, virus shedding was reduced from 3.64 log10TCID50 in control animals to 2.59 log10TCID50 in vaccinated animals. On days 6 and 8 after BRSV challenge, there were fewer vaccinated animals (n=2/10 and 0/10, respectively) shedding the virus than control animals (n=8/10 and 3/10, respectively). Moreover, after challenge, the mean duration of virus shedding was reduced from 3.8 days in control animals to 1 day in vaccinated animals in the BVDV study and from 3.4 days in control animals to 1.2 days in vaccinated animals in the BRSV study. The duration of immunity of >or =6 months for PI3V, BHV-1 and BVDV, and 12 months for BRSV, after vaccination with Rispoval 4, was associated mainly with enhanced post-challenge antibody response to all four viruses and reduction of the amount or duration of virus shedding or both.
    Preventive Veterinary Medicine 01/2005; 66(1-4):63-77. · 2.51 Impact Factor
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    ABSTRACT: Objective: Aim of the present study was to demonstrate the relevance of the vaccine strain of a new BVD vaccine, PregSure® BVD, for its use in Europe. Furthermore the vaccine¿s ability to protect from pregnancy losses due to an early infection with BVDV after artificial insemination was determined. Material and methods: The immune sera used in the in-vitro cross neutralisation were collected from 20 heifers three weeks after the completion of the primary vaccination schedule with PregSure® BVD (two vaccinations given 21 days apart). The BVDV cross-neutralising activity of these postvaccinal sera was tested by virus neutralisation employing a panel of different predominantly European BVDV type I and II strains. Furthermore, two fertility studies were carried out, where heifers between 14 and 39 months of age were primovaccinated with PregSure® BVD or left untreated as control, respectively. All animals had their oestrus cycles synchronised and were artificially inseminated. Four days after the initial artificial insemination and again three days later, all animals of experimental group 1 were challenged intranasally with two heterologous noncytopathic BVDV type I strains, whereas animals from group 2 received a type I and a type II BVDV strain. Sixty-nine to 72 days after the challenge, all dams were slaughtered and their foetuses collected. Differences in pregnancy rates between the vaccinated and the control group were assessed and then analysed using Fisher¿s Exact Test. Results: Heifers vaccinated with a novel inactivated BVDV vaccine containing a cytopathic BVDV type I strain 5960, were shown to have serum neutralising antibody titres between 5.5 to 12.3 log2 against all BVDV strains tested, three weeks after the completion of their primary vaccination course. In the first fertility experiment, pregnancy rates assessed 69-72 days after a double challenge with two different BVDV type I strains were 95.5% in the vaccinated group versus only 40.9% in the control group. A level of cross-protection against a severe BVDV type II challenge was shown in the second experiment with pregnancy rates of 47.6% in the vaccinated group and only 4.4% in the control group. Conclusions and clinical relevance: The broad cross neutralising activity shown in this study demonstrates the relevance of the vaccine strain 5960 for use in Europe. Furthermore as shown with significantly improved pregnancy in the two fertility experiments, PregSure® BVD vaccinated heifers are protected against fertility losses caused by acute BVDV infections.
    Tierarztliche Praxis Ausgabe Grosstiere Nutztiere. Ausgabe G: Großtiere, Nutztiere 32 (2004) 4. 01/2004;
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    ABSTRACT: The field efficacy and safety of a single-dose Mycoplasma hyopneumoniae vaccine were evaluated in three-to five-week-old pigs. Two field efficacy studies were conducted, one in England with 673 pigs, and one in Germany with 719 pigs. The pigs were injected intramuscularly with either the vaccine or saline (control) at a ratio of 2:1 and reared under commercial conditions to slaughter weight. The efficacy of the vaccine was evaluated by comparing the lung lesions associated with infection with M. hyopneumoniae in the control and vaccinated animals postmortem. In both countries the vaccinated pigs had a significantly lower percentage of lung lesion scores, in England 5.7 v 10.2 per cent (P = 0.0022) and in Germany 3.9 v 7.7 per cent (P = 0.0056). In Germany the average daily weight gain (ADG) of the vaccinated pigs was significantly higher (639 g v 616 g) (P = 0.0205). In both countries and in both the treated and control animals there was a significant negative correlation between the ADG and the lung lesion score (P = 0.0001). Two safety trials were conducted, one in England and one in Germany, each with 75 pigs, and in each case 50 pigs were given the maximum batch release antigen titre of the vaccine and 25 were given saline. The safety of the vaccine was evaluated by observation for local and systemic reactions and any increases in rectal temperature. No abnormal reactions were observed in the vaccinated pigs and there was no significant difference between the mean peak rectal temperatures of the vaccinated and control pigs in either trial.
    The Veterinary record 12/2002; 151(18):535-8. · 1.63 Impact Factor
  • Cattle practice: The Journal of the British Cattle Veterinary Association 174 (2005) 13.