Seroprevalence of Swine Influenza A Virus (swIAV) Infections in Commercial Farrow-to-Finish Pig Farms in Greece.

Swine influenza is a highly contagious respiratory disease caused by influenza A virus infection. Pigs play an important role in the overall epidemiology of influenza because of their ability to transmit influenza viruses of avian and human origin, which plays a potential role in the emergence of zoonotic strains with pandemic potential. The aim of our study was to assess the seroprevalence of Swine Influenza Viruses (swIAVs) in commercial pig farms in Greece. A total of 1416 blood samples were collected from breeding animals (gilts and sows) and pigs aged 3 weeks to market age from 40 different swIAV vaccinated and unvaccinated commercial farrow-to-finish pig farms. For the detection of anti-SIV antibodies, sera were analyzed using an indirect ELISA kit CIVTEST SUIS INFLUENZA®, Hipra (Amer, Spain). Of the total 1416 animals tested, 498 were seropositive, indicating that the virus circulates in both vaccinated (54% seroprevalence) and unvaccinated Greek pig farms (23% seroprevalence). In addition, maternally derived antibody (MDA) levels were lower in pigs at 4 and 7 weeks of age in unvaccinated farms than in vaccinated farms. In conclusion, our results underscore the importance of vaccination as an effective tool for the prevention of swIAV infections in commercial farrow-to-finish pig farms.

Effects of Injectable Administration of Dexamethasone Alone or in Combination with Vitamin E/Se in Newborn Low Birth Weight Piglets.

Increasing litter size may lead to low-birth-weight piglets (LBW) and further negative long-term effects. This study aimed to evaluate the effects of intramuscular administration (IM) of dexamethasone (Dexa) alone or in combination with vitamin E/Se on LBW piglets during the early postnatal period. The study included a total of 100 LBW piglets that were divided into 5 groups (20 LBW piglets per group) and treated with IM Dexa alone or in combination with vitamin E/Se (Vit E/Se) after birth as follows: (a) Group A-Cont: Control group, (b) Group B-Dexa1: Dexa on D1 (1st day of life), (c) Group C-Dexa3: Dexa on D1, D2, D3 (D2: 2nd day of life, D3: 3rd day of life), (d) Group D-Dexa + VitE/S1: Dexa + Vit E/Se on D1, and (e) Group E-Dexa + VitE/S3: Dexa + Vit E/Se (IM) on D1, D2, D3. Body weight (BW) and the Average Daily Weight Gain (ADWG) were recorded for all piglets on days 1, 7, 14, and 25, and vitality score (VS) was recorded on days 1, 2, 3, 4, and 14. A significant increase in BW and ADWG in Group E-Dexa + VitE/S3 and a significant reduction in Group C-Dexa3 were noticed in comparison to other groups. VS in groups Group B-Dexa1 and Group C-Dexa3 were significantly lower in comparison to other groups. Furthermore, piglets of Group C-Dexa3 had a significantly higher frequency of clinical findings compared to other groups. In conclusion, the administration of Dexa and vitamin E/Se combined after the birth of LBW piglets for 1-3 days has beneficial effects on their growth and survival scores.

Angiotensin II Blood Serum Levels in Piglets, after Intra-Dermal or Intra-Muscular Vaccination against PRRSV.

The Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) induces apoptosis in different organs. Angiotensin II (Ang II) is the main effector of the renin-angiotensin system and participates in apoptosis. Thus, this study aimed to investigate changes in piglet serum Ang II levels following intradermal (ID) and intramuscular (IM) vaccination with a commercial PRRS modified live virus (MLV) vaccine. The trial was conducted in a commercial pig farm, including 104 piglets which were randomly allocated to four groups: Group A-Porcilis PRRS ID, Group B-Porcilis PRRS IM, Group C-Diluvac ID and Group D-Diluvac IM. The study piglets were either vaccinated or injected at 2 weeks of age and they were tested by qRT-PCR for PRRSV and by ELISA for Ang II. The results indicated differences in viremia of tested piglets at 7 weeks of age, while piglets at 10 weeks of age were all found qRT-PCR positive for PRRSV. In addition, significant differences were noticed in Ang II in 7-week-old piglets. In conclusion, the present study provides evidence that ID vaccination induces less tissue damage, based on the lower measurements of Ang II in the serum of ID vaccinated piglets.

Investigation of Fas (APO-1)-Related Apoptosis in Piglets Intradermally or Intramuscularly Vaccinated with a Commercial PRRSV MLV.

Porcine reproductive and respiratory syndrome virus (PRRSV) induces apoptosis through the activation of death receptors, including cell-surface Fas receptor. The aim of this study was to investigate the impact of intradermal (ID) and intramuscular (IM) vaccination with a commercial PRRSV-modified live vaccine in piglets on Fas-related apoptosis. The study included 104 suckling piglets from a commercial farrow-to-finish pig farm, suffering from positive unstable PRRSV status. Animals were assigned in four groups: group A-Porcilis PRRS ID-vaccinated pigs, group B-Porcilis PRRS IM-vaccinated pigs, group C-Diluvac ID adjuvant-administered pigs, and group D-Diluvac IM adjuvant-administered pigs. Vaccines were administered at 2 weeks of age. Blood samples were collected from the same pigs at 4, 7, and 10 weeks of age. Sera were examined by quantitative real-time reverse transcription-PCR (qRT-PCR) for PRRSV and by ELISA for soluble Fas (sFas). At 4 weeks of age, all groups were negative qRT-PCR for PRRSV; at 7 weeks only group A was negative; and at 10 weeks all groups were positive. sFas was significantly increased in groups C (4 vs. 7, 4 vs. 10, and 7 vs. 10 weeks) and D (7 vs. 10 weeks). Significant differences among groups were noticed only at 10 weeks (A vs. C, A vs. D, B vs. C, B vs. D). A significant positive and moderate correlation between PRRSV viral load and Fas level was observed. In unvaccinated piglets, increased serum sFas levels reveal apoptotic suppression compared with vaccinated piglets. In the latter, vaccine-derived antibodies limit the infection and may attribute to the reduced Fas expression, suggesting a weak induction of lymphocyte-mediated cytotoxicity.

Evaluation of Intradermal PRRSV MLV Vaccination of Suckling Piglets on Health and Performance Parameters under Field Conditions.

Porcine reproductive and respiratory syndrome virus (PRRSV) causes respiratory disease in weaning and growing pigs. A vaccination against PRRSV is one of the most important control measures. This trial aimed to evaluate the effect of the intradermal (ID) administration of a PRRSV-1 modified live virus (MLV) vaccine in comparison to the intramuscular (IM) administration on the piglets' health and performance. A total of 187 suckling piglets of a PRRSV-positive commercial farrow-to-finish farm were assigned to four groups: group A­PRRSV ID, group B­PRRSV IM, group C­control ID, and group D­control IM. At 2 weeks of age, all the study piglets were either vaccinated with a PRRSV-1 MLV vaccine or injected with the vaccine adjuvant (controls). The collected blood serum samples were tested by ELISA and qRT-PCR. The side effects, body weight (BW), average daily gain (ADG), mortality rate, and lung and pleurisy lesions scores (LLS, PLS) were also recorded. The ELISA results indicated that the vaccination induced an important seroconversion at 4 and 7 weeks. Significant differences in the qRT-PCR results were noticed only at 10 weeks in group A vs. group C (p < 0.01) and group B vs. group C (p < 0.05). High viral loads, as evidenced by the qRT-PCR Ct values, were noticed in animals of both non-vaccinated groups at 7, 10, and 13 weeks. An ID vaccination has a positive impact on the BW at the piglets' slaughter, while both an ID and IM vaccination had a positive impact on the ADG. The mortality rate was lower in vaccinated groups at the finishing stage. The LLS and PLS were significantly lower in the vaccinated groups. In conclusion, our study demonstrated that the ID vaccination of suckling piglets with a PRRSV-1 MLV vaccine has a positive effect on the piglets' health and performance, including an improved BW and a lower LLS and PLS index at their slaughter, as well as a decreased mortality rate at the growing/finishing stage.

First-Time Detection of Porcine Reproductive and Respiratory Syndrome Virus and Porcine Circovirus 2 in an Albanian Farrow-to-Finish Herd.

The purpose of this case report is to describe for the first time concurrent porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus 2 (PCV-2) infections in a commercial farrow-to-finish pig farm in Albania, as well as the phylogenetical analysis of isolated PRRSV strain. The present study reports on a farrow-to-finish commercial pig farm, located in South Albania. In a percentage of about 40% of weaners in each batch (60-70 piglets per batch), clinical signs, including fever, severe respiratory signs, wasting, jaundice, rough hairy coat, palpable inguinal lymphadenopathy, and high mortality rate, were performed. The clinical signs of sows included sporadic premature farrowings (22%), with increased number of stillbirth (3.3%) and weak piglets (4.1%) based on the record system of the farm. Blood samples were obtained from 8 sows (4 lactating and 4 dry-period sows), 25 piglets of 5 different batches (5 at 15-20 days, 5 at 40 days, 5 at 50 days, 5 of 60 days, and 5 of 70 days), and 5 finishers of 130-150 days of age. Moreover, tissue samples were collected from five weaners at 20-70 days of age. Histopathological examination of lung and lymph node sections revealed findings compatible with PRRSV and PCV-2 infection. Pigs between 15 and 130-140 days of age were positive for type 1 (European) PRRSV and pigs between 50 and 130-140 days of age were positive for PCV-2. Blood serum samples were tested by real-time polymerase chain reaction (PCR) for PCV-2 and one real-time reverse transcription-PCR-positive sample was selected for subsequent complete ORF5 (Gp5) gene sequencing. The results of this case report confirm the detection of PRRSV and PCV-2 concurrent infection in an Albanian farrow-to-finish pig farm. The full-length ORF5 sequence of the detected PRRSV strain (named "Mursi/AL/15") was successfully determined, revealing high nucleotide identity with other type 1 European isolates.