A.R. Peters

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

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Publications (9)7.95 Total impact

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    ABSTRACT: Two independent studies assessed the duration of immunity of an inactivated adjuvanted Mycoplasma hyopneumoniae vaccine against mycoplasmal pneumonia in seronegative (study A, n=52) and seropositive (study B, n=52) pigs. The pigs were allocated randomly to treatment and were then injected with a single dose of either the vaccine or a placebo at approximately 1 week of age. Twenty-five weeks after treatment administration, the pigs were challenged with a virulent strain (LI 36, Strain 232) of M. hyopneumoniae and the extent of lung lesions consistent with mycoplasmal pneumonia was assessed 4 weeks later. In study A, the geometric mean lung lesion score (expressed as least squares mean percentages of lung lesions) was significantly (P=0.0001) lower in vaccinated (0.3%, n=20) than in control pigs (5.9%, n=24) seronegative to M. hyopneumoniae at enrolment; similarly, in study B, the extent of lung lesions was significantly reduced (P=0.0385) in seropositive vaccinated pigs (2.0%, n=22) compared to controls (4.5%, n=26). At the end of the investigation period, 4 weeks after challenge, mean antibody sample-to-positive (S/P) ratios were significantly higher both in seronegative (P=0.0012) and seropositive (P=0.0001) vaccinated pigs (mean values=0.77 and 0.81, respectively) than in controls (mean values=0.51 and 0.38, respectively).
    No preview · Article · Jul 2008 · The Veterinary Journal
  • J S Salt · S J Thevasagayam · A Wiseman · A.R. Peters
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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).
    No preview · Article · Dec 2007 · The Veterinary Journal
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    ABSTRACT: The time of onset of immunity after a single vaccination of piglets at 5-10 days of age against Mycoplasma hyopneumoniae with the vaccine Stellamune® One (Respisure® One; Pfizer Inc.) was investigated. Fifty per cent of the test animals were challenged intranasally 14 and 15 days and the remaining 50% at 20 and 21 days after vaccination or following the administration of a placebo. Piglets challenged 14 and 15 days post vaccination had statistically significant fewer marked lesions compared to the controls (12.4% vs. 38.0%). This was also the case for piglets challenged 20 and 21 days post vaccination (13.9% vs. 34.0%) (p < 0.05). The percentage of animals with an increase in antibody titres against Mycoplasma hyopneumoniae by the end of the study was greater in the vaccinated groups than in the unvaccinated control groups (52.38% vs. 4.76% after challenge on days 14 and 15 and 62.5%. vs. 9.09% after challenge on days 20 and 21). The results of the study demonstrate an onset of immunity against Mycoplasma hyopneumoniae 2 weeks after a single vaccination of piglets at the age of approximately 1 week. The importance of the results for the control of the Porcine Respiratory Disease Complex (PRDC) is discussed.
    No preview · Article · Jun 2006
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    ABSTRACT: Bovine respiratory syncytial virus (BRSV) is a widespread cause of lower respiratory tract disease in cattle. Calves less than four months of age are often involved in outbreaks of respiratory disease. We evaluated the efficacy of a single intranasal dose of a bivalent modified live vaccine containing BRSV (Rispoval® RS+Pi3 Intranasal, Pfizer Ltd.) in three-week-old calves with and without maternal antibodies to BRSV. Two experimental challenge studies were undertaken. In the first study, the time to onset of protection following vaccination was determined in three-week-old colostrum deprived (maternal antibody negative) calves. Calves were challenged at 5, 10 or 21 days after vaccination. Onset of immunity was demonstrated within 5 days after vaccination. After challenge, clinical signs were mostly mild and differences between vaccinated calves and controls were small but the duration of coughing (indicative of upper respiratory tract disease) was significantly shorter in the vaccinates challenged 10 days after vaccination (P = 0.0059) and the duration of hyperpnoea (indicative of lower respiratory tract disease) was significantly shorter in the vaccinates challenged 5 days after vaccination (P = 0.0253). In the second study, the efficacy of the vaccine was assessed in three-week-old calves with maternal antibodies to BRSV. Vaccination significantly reduced BRSV nasal shedding after challenge 9 weeks post vaccination and a strong serological booster response was observed in the vaccinated calves following challenge. In addition, clinical signs of respiratory tract disease following challenge were less severe in the vaccinates than the controls with a lower number of mortalities in the vaccinated calves. It is concluded that a single intranasal dose of the bivalent modified live vaccine containing BRSV (Rispoval® RS+Pi3 Intranasal, Pfizer Ltd.) provided significant protection against BRSV shedding and disease in young calves both with and without maternal antibodies to BRSV.
    No preview · Article · Oct 2005 · Cattle Practice
  • AR Peters · S J Thevasagayam · A Wiseman · J S Salt
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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.
    No preview · Article · Jan 2005 · Preventive Veterinary Medicine
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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.
    No preview · Article · Jan 2004 · Tierärztliche Praxis. Ausgabe G, Grosstiere/Nutztiere
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    ABSTRACT: The efficacy of a single dose Mycoplasma hyopneumoniae vaccine (Stellamune® Mono injection, Pfizer Animal Health) was evaluated in 767 pigs aged between three and five weeks on the day of vaccination. The study was carried out in France under field conditions. The extent of lung lesions was significantly reduced in vaccinated animals (2.4%) compared with control animals (7.7%). Furthermore, the prevalence of lung lesions at slaughter was significantly lower in vaccinated pigs (50.0%) than in control pigs (73.4%). Finally, the average daily weight gain was significantly higher in vaccinated animals (660 g/day) than control animals (642 g/day). The results presented in this paper demonstrate the efficacy of Stellamune® Mono injection in conferring protection in pigs, aged three to five weeks on the day of vaccination, against enzootic pneumonia.
    Full-text · Article · Nov 2003
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    ABSTRACT: The efficacy of a single dose Mycoplasma hyopneumoniae vaccine (Stellamune® One, Pfizer Animal Health) was evaluated in pigs at approximately one week of age under field conditions. The study was conducted in two commercial farrowing-to-finishing farms located in Britanny (France). A total of 293 pigs was enrolled. They received either the vaccine or a saline placebo between 7 and 10 days of age. For the duration of the study, normal management pracrices were maintained in each herd. Criteria for the evaluation of efficacy included prevalence and extent of lung lesions at slaughter and growth performance. The extent of lung lesions was significantly (p = 0,0457) reduced in vaccinated animals (5,9 %) compared to control animals (9,1 %). Additionally, the prevalence of lung lesions at slaughter was lower in vaccinated pigs (65,8 %) than in control pigs (74,1 %). Average daily weight gain was higher in vaccinated pigs (618,5 g/day) compared to control pigs (607,3 g/day). The results presented in this paper demonstrate the efficacy of Stellamune® One in reducing the severity of lung lesions in pigs vaccinated at one week of age.
    No preview · Article · Jun 2003 · Tierärztliche Umschau
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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.
    Preview · Article · Dec 2002 · The Veterinary record