Efficacy Studies against PCV-2 of a New Trivalent Vaccine including PCV-2a and PCV-2b Genotypes and Mycoplasma hyopneumoniae When Administered at 3 Weeks of Age.

This study aimed to evaluate the efficacy of a new trivalent vaccine containing inactivated Porcine Circovirus 1-2a and 1-2b chimeras and a Mycoplasma hyopneumoniae bacterin administered to pigs around 3 weeks of age. This trivalent vaccine has already been proved as efficacious in a split-dose regimen but has not been tested in a single-dose scenario. For this purpose, a total of four studies including two pre-clinical and two clinical studies were performed. Globally, a significant reduction in PCV-2 viraemia and faecal excretion was detected in vaccinated pigs compared to non-vaccinated animals, as well as lower histopathological lymphoid lesion plus PCV-2 immunohistochemistry scorings, and incidence of PCV-2-subclinical infection. Moreover, in field trial B, a significant increase in body weight and in average daily weight gain were detected in vaccinated animals compared to the non-vaccinated ones. Circulation of PCV-2b in field trial A and PCV-2a plus PCV-2d in field trial B was confirmed by virus sequencing. Hence, the efficacy of this new trivalent vaccine against a natural PCV-2a, PCV-2b or PCV-2d challenge was demonstrated in terms of reduction of histopathological lymphoid lesions and PCV-2 detection in tissues, serum and faeces, as well as improvement of production parameters.

Efficacy Studies of a Trivalent Vaccine Containing PCV-2a, PCV-2b Genotypes and Mycoplasma hyopneumoniae When Administered at 3 Days of Age and 3 Weeks Later against Porcine Circovirus 2 (PCV-2) Infection.

Four studies under preclinical and clinical conditions were performed to evaluate the efficacy of a new trivalent vaccine against Porcine circovirus 2 (PCV-2) infection. The product contained inactivated PCV-1/PCV-2a (cPCV-2a) and PCV-1/PCV-2b (cPCV-2b) chimeras, plus M. hyopneumoniae inactivated cell-free antigens, which was administered to piglets in a two-dose regime at 3 days of age and 3 weeks later. The overall results of preclinical and clinical studies show a significant reduction in PCV-2 viraemia and faecal excretion, and lower histopathological lymphoid lesions and PCV-2 immunohistochemistry scores in vaccinated pigs when compared to non-vaccinated ones. Furthermore, in field trial A, a statistically significant reduction in the incidence of PCV-2-subclinical infection, an increase in body weight from 16 weeks of age to slaughterhouse and an average daily weight gain over the whole period (from 3 days of age to slaughterhouse) was detected in the vaccinated group when compared to the non-vaccinated one. Circulation of PCV-2a in field trial A, and PCV-2b plus PCV-2d in field trial B was confirmed by virus sequencing. In conclusion, a double immunization with a cPCV-2a/cPCV-2b/M. hyopneumoniae vaccine was efficacious against PCV-2 infection by reducing the number of histopathological lymphoid lesions and PCV-2 detection in tissues, serum, and faeces, as well as reducing losses in productive parameters.

Vaccination of piglets up to 1 week of age with a single-dose Mycoplasma hyopneumoniae vaccine induces protective immunity within 2 weeks against virulent challenge in the presence of maternally derived antibodies.

Enzootic pneumonia, resulting from infection with Mycoplasma hyopneumoniae, is of considerable economic importance to the pig industry and normally is controlled through active vaccination of piglets. We have demonstrated that administration of an inactivated Mycoplasma hyopneumoniae vaccine to piglets less than 1 week old is efficacious under field conditions and reduces the level of lung lesions observed in comparison to that in control pigs. Here, the results of two separate studies, one in piglets with and the second one in piglets without maternal antibodies, conducted to satisfy the requirements of the European Pharmacopoeia (monograph no. 07/2009:2448), are reported. Piglets received either minimal titer Suvaxyn MH-One or saline at less than 1 week of age and were challenged with Mycoplasma hyopneumoniae 2 weeks later. The number of lung lesions was recorded 4 weeks after challenge, and bronchial swab and lung tissue specimens were analyzed for quantification of Mycoplasma hyopneumoniae DNA. In the presence and absence of maternal antibodies, vaccination of piglets at less than 1 week of age was efficacious, with vaccinated piglets having significantly lower percentages of lung with lesions and lower Mycoplasma hyopneumoniae counts detected in bronchial swab and lung tissue specimens at necropsy. In conclusion, the vaccination of piglets at 1 week of age with Suvaxyn MH-One is efficacious in the presence of high levels of maternal antibodies.

Vaccination of piglets at 1 week of age with an inactivated Mycoplasma hyopneumoniae vaccine reduces lung lesions and improves average daily gain in body weight.

The field efficacy and safety of a single-dose inactivated Mycoplasma hyopneumoniae vaccine, Suvaxyn MH-One, was evaluated in 4-5-day-old piglets on a commercial farm with a history of Mycoplasma disease in Southern Germany. The piglets were injected intramuscularly with the vaccine or saline (control group) and raised under commercial conditions to slaughter weight. The efficacy of the vaccine was determined by comparing the lung lesions associated with infection by M. hyopneumoniae in control and vaccinated pigs post mortem. In this analysis the vaccinated pigs had the lower mean percentage lung lesion at 5% compared to 9% in controls. Of the vaccinated pigs 52.3% were shown to have low levels of lung lesions between 0% and 5% and no more than 5.4% were shown to have levels above 20%. In contrast, the pigs administered saline showed 36.5% in the lower category (0-5%), while 18.3% showed lesions greater than 20%. There were significant differences in the mean body weight of pigs at the final two weight measurements at approximately 21 weeks and 26 weeks of age, with those receiving Suvaxyn MH-One being on average 5 kg heavier at each time point. There was also a significant increase in average daily gain in the vaccinated animals compared to the control group, particularly in the period from vaccination to the final two body weight measurements on day 138 and 166, from weaning at day 28 to the final two body measurements and from mid-way during finishing at day 84 to the final two body weight measurements. Vaccination had no adverse impact on appetite, although small numbers of vaccinated and control pigs did show mild signs of coughing, sneezing, respiratory distress or depression. There was no adverse impact on rectal temperatures and no signs of injection site reactions during the course of the study. We can conclude that vaccination with Suvaxyn MH-One to pigs at less than 1 week of age is effective in reducing lung lesions resulting from M. hyopneumoniae and also aids growth performance by reducing weight losses and improving average daily gain.

Difficulties in demonstrating long term immunity in FeLV vaccinated cats due to increasing age-related resistance to infection.

BACKGROUND: Feline leukaemia virus (FeLV) is a pathogen causing fatal illness in cats worldwide, and as such there is a high demand for products to protect against disease. The duration of immunity provided by an inactivated FeLV vaccine, Versifel FeLV, when administered to cats of the target age was determined. Kittens received two vaccinations when aged 7 to 9 weeks old, and were subsequently challenged up to 36 months later with the FeLV-A Glasgow isolate. RESULTS: In all studies, all of the younger aged control kittens showed persistent FeLV p27 antigenaemia confirming that the challenge virus was severe and efficacious. In contrast, the control cats did not show the required level of persistent antigenaemia, with a maximum of 45% cats affected in the middle duration study and only 10% in the longer study. However, apart from one animal in the short duration study, all of the cats vaccinated with Versifel FeLV were negative for persistent antigenaemia and can be considered treatment successes. CONCLUSION: In conclusion, we have shown that although age-related resistance to infection with a virulent FeLV challenge is evident from as early as 10 months of age, vaccination with Versifel FeLV may aid in the protection of cats from FeLV related disease up to three years after primary vaccination as kittens.