Immunohistochemical detection of aetiological agents of proliferative and necrotizing pneumonia in Italian pigs

Proliferative and necrotizing pneumonia (PNP) is a form of interstitial pneumonia that occurs in weaning and post-weaning pigs. PNP is characterized by hypertrophy and hyperplasia of type II pneumocytes and coagulative necrosis and granular debris within alveolar spaces. Canadian and European studies suggest that the porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are the main causes of the disease, but Aujezsky's disease virus (ADV) and swine influenza virus (SIV) have also been considered as potential aetiological agents. An immunohistochemical study was carried out on the lungs of 28 Italian pigs with PNP in order to evaluate the role of PRRSV, PCV2 and ADV in PNP lesions. PRRSV infection was identified in the lungs of 11 pigs, PCV2 in the lungs of four pigs and coinfection with both viruses in the lungs of eight pigs. Neither virus was detected in the lungs of the remaining five pigs. ADV antigen was not detected in any sample. The principle aetiological agent of PNP in Italy therefore appears to be PRRSV. Coinfection with PRRSV and PCV2 is characterized by more severe microscopical changes in affected lungs

Effectiveness of sow vaccination with CIRCOVAC\uae (Merial) in a PCV2-positive but PCVD-free herd under Italian conditions

The objective of this study was to assess the efficacy of CIRCOVAC sow vaccination, in reducing mortality and improving growth of the offspring, in a PCV2 positive, PMWS negative herd (absence of PCVD), under Italian conditions. Sow vaccination with CIRCOVAC, induced a significant improvement in overall piglet mortality rate and an increase of the ADWG was seen from 68 days to slaughter, confirming other works

Comparative evaluation of two PCV2 vaccines in piglets

Introduction. At present in Europe several commercial PCV2 vaccines are available for use in piglets. One of these is also licensed for sows. Under field conditions, all PCV2 vaccines available are effective, showing decreased mortality and cull rates and significantly improving average daily weight gain (ADWG). The objective of this study was to compare the efficacy of two PCV2 vaccines. Materials and methods. A controlled, blinded and randomized field study was performed on an Italian 420-sow farrow-to-finish farm without PCVD anamnesis. One thousand and fifty piglets, from five consecutive batches, were included in this trial. The piglets were stratified by sex, weight, parity of the sow and randomly allocated to 3 groups. At weaning, each piglet received 0.5 ml Circovac\uae i.m. (Group A) or 1 ml Circoflex\uae i.m. (Group B). The pigs in Group C were not vaccinated and kept as control animals. Control and vaccinated piglets stayed intermingled. All animals were vaccinated against M. hyopneumoniae 2 days before PCV2 vaccinations, with a one-shot W/O vaccine. The body weight was determined at 25, 110 and 225 days of age (d). All animals were monitored for clinical symptoms and mortality was recorded during the whole study period. Only batch 3 was chosen for collection of laboratory data in order to assess the impact of vaccination on viral pressure over time. Blood samples were collected monthly and serum samples of Circovac\uae vaccinated (n=12), Circoflex\uae vaccinated (n=13), as well as of control animals (n=11) were analyzed by a competitive ELISA. Pooled sera from at least 3 subjects were analyzed by quantitative PCR (qPCR). The ADWG from 25d to 105d, 105d to 220d and from 25d to 220d in the different groups were compared. The comparison was made by assessing any differences between: a) vaccinated subjects (groups A and B) to group C, b) vaccinated with Circovac\uae or with Circoflex\uae to non-vaccinated animals (group C), d) vaccinated with Circovac\uae to animals vaccinated with Circoflex\uae. Results. In the periods 25-105d, 105-220d and 25-220d the AWDG of vaccinated subjects were significantly higher (respectively: Mann-Whitney U=97767, p<0.01; U=97477, p<0.05; U=92101, p<0.01) than those of the control animals. Both animals vaccinated with Circovac\uae and those vaccinated with Circoflex\uae showed ADWG significantly higher (p<0.05) than those of the control group during the three considered periods. The difference between ADWG of group B and group A was not statistically significant for any of the three time periods. The percentage of 25-to-220-day dead pigs and runts: 5.73%, 6.26% and 6.28% for groups A, B and C, respectively, were very similar; however, incidence of underweight pigs was statistically lower in the vaccinated groups. Antibodies titre and serum viral load were statistically lower in vaccinated subjects. Discussion. Compared to the control group, vaccinated animals showed a significant increase of ADWG. Vaccinated animals had a lower titre of PCV2 specific antibodies and the vaccination seemed to reduce the viral pressure in the facilities. This observation is supported by the qPCR data, which showed, that vaccinated animals had a lower serum viral load. No statistically significant difference in the considered parameters was observed between the two vaccines

Scanner photography: effective technique to investigate needle free device injection dispersion pattern

Vaccination, allowing to contain infections and to prevent health problems is a crucial strategic management tool in today's pig industry. However, it also represents a cost item and therefore condition of vaccine application must be optimized. In the recent years needle free injection devices (NFID) have utilized various techniques for transcutaneous vaccine injections. Among the benefits to be highlighted there are: no broken needles in the meat, reduced inter animal transmission of diseases, respect of animal welfare. In this paper a scanographic (scanner photography) technique will be illustrated, for analyzing and quantifying transport / pattern of penetration and dispersion of a vaccine administered by NFID in piglets focussing on macroscopical visual injection outcome. Conventional piglets of 5-20 kg lbw were vaccinated on the left side of the neck with NFID Valery\uae (Giordano Poultry Plast, Caraglio Cuneo, Italy) with black china ink spiked CIRCOVAC\uae (MERIAL, Lyon, France), 1 cc ink/100 cc of vaccine), according to datasheet (0.5 ml/piglet) and immediately underwent euthanasia. Freezing of hanged piglets was carried out (48 h, -20\ub0C) and subsequently frozen cross-sectional slices were obtained (thickness about 1 cm). Images were acquired by means of an ordinary flatbed scanner protected by a glass platen (hp, Palo Alto-CA, USA). Mechanism of liquid jet injectors relies on the principle of forcing fluids through a small orifice, generating a high pressured stream that penetrates into the skin with high velocity. There are numerous predictive \u201cpreskin\u201d biophysical trials and predictive models, but there are rare models of evaluation of intramuscular penetration, and dispersion characteristics in vivo. Therefore the proposed method provides valuable and reliable information, is objective, repeatable and reproducible, not expensive, and allows the comparison of in vivo efficacy of various NFID