The introduction of a highly virulent PRRSV strain in pig farms is associated with a change in the pattern of influenza A virus infection in nurseries.

The present study aimed to determine the dynamics of influenza A virus (IAV) infection in two endemically infected farms (F1 and F2), where a longitudinal follow-up of piglets was performed from birth to 8-12 weeks of age. During the study, a highly virulent isolate of porcine reproductive and respiratory syndrome virus (PRRSV) was introduced on both farms. This allowed us to examine the impact of such introduction on the patterns of infection, disease, and the antibody response of pigs to IAV infection.

Selection of viral variants with enhanced transmission and reduced neutralization susceptibility alongside lateral introductions may explain the persistence of porcine reproductive and respiratory syndrome virus in vaccinated breeding herds.

This study investigates the long-term evolutionary dynamics of porcine reproductive and respiratory syndrome virus (PRRSV-1) in an endemically infected and vaccinated pig herd. Over a one year and a half period, piglets from seven farrowing batches in a 300-sow PRRSV-vaccinated farm were monitored from birth to nine weeks of age by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Eighty-five PRRSV-positive samples were subjected to whole genome sequencing (Illumina Miseq), and 251 samples to open reading frame 5 (ORF5) sequencing.

The scene of lung pathology during PRRSV-1 infection.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important infectious diseases for the pig industry worldwide. The disease was firstly reported in 1987 and became endemic in many countries. Since then, outbreaks caused by strains of high virulence have been reported several times in Asia, America and Europe.

Characterization of biosecurity practices among cattle transport drivers in Spain.

Transmission of pathogens between farms via animal transport vehicles is a potential concern; however, the available information on driver routines and biosecurity measures implemented during transport is limited. Given the above, the aim of this study was to describe and characterize the prevailing practices and biosecurity measures adopted by cattle transport drivers in Spain. Eighty-two drivers were surveyed via face-to-face or remotely.

Levels of neutralizing antibodies against resident farm strain or vaccine strain are not indicators of protection against PRRSV-1 vertical transmission under farm conditions.

Background: Vertical transmission is key for the maintenance of porcine reproductive and respiratory syndrome virus (PRRSV) infection. In vaccinated farms, vertical transmission can still occur despite sows having some level of immunity because of repeated vaccination or contact with the wild-type virus. The present study aimed to correlate the age of sows and the amplitude of neutralizing antibodies (Nab) (heterologous neutralization) with PRRSV-1 vertical transmission (VT).

High levels of maternally derived antibodies do not significantly interfere with the development of humoral and cell-mediated responses to Porcine circovirus 2 after intradermal vaccination.

Background: Vaccination of pigs against PCV2 is usually performed around weaning when animals still have maternally derived antibodies (MDA). The present study aimed to assess the possible interference of MDA in the development of the PCV2-specific immune response after vaccination of commercial weaners. For this purpose, a PRRS-negative 600-sow farrow-to-finish farm was selected.

Infection dynamics, transmission, and evolution after an outbreak of porcine reproductive and respiratory syndrome virus.

The present study was aimed at describing the infection dynamics, transmission, and evolution of porcine reproductive and respiratory syndrome virus (PRRSV) after an outbreak in a 300-sow farrow-to-wean farm that was implementing a vaccination program. Three subsequent batches of piglets (9-11 litters/batch) were followed 1.5 (Batch 1), 8 (Batch 2), and 12 months after (Batch 3) from birth to 9 weeks of age.

Systemic CD4 cytotoxic T cells improve protection against PRRSV-1 transplacental infection.

Background: (PRRSV) is one of the major swine pathogens causing reproductive failure in sows. Although modified-live virus (MLV) vaccines are available, only partial protection against heterologous strains is produced, thus vaccinated sows can be infected and cause transplacental infection. The immune effector mechanisms involved are largely unknown.

Introduction of a PRRSV-1 strain of increased virulence in a pig production structure in Spain: virus evolution and impact on production.

Background: A strain of Porcine reproductive and respiratory syndrome virus (PRRSV), showing characteristics of enhanced virulence, affected a pyramidal production system from Spain with 7600 sows in 4 genetic nuclei and 13,000 sows in multipliers. Different PRRSV strains circulating in this production system from December 2020 to October 2021 were detected and sequenced. The spread of each isolate was examined and their impact on health and production in three of the affected farms was evaluated.

Diversity of respiratory viruses present in nasal swabs under influenza suspicion in respiratory disease cases of weaned pigs.

Respiratory diseases in weaned pigs are a common problem, with a complex etiology involving both viruses and bacteria. In the present study, we investigated the presence of eleven viruses in nasal swabs, collected from nurseries (55 cases) under the suspicion of (swIAV) and submitted by swine veterinarians for diagnosis. The other ten viruses included in the study were influenza B (IBV) and D (IDV), (PRRSV), (PRCV), (PCMV), 2 (PCV2), 3 (PCV3) and 4 (PCV), (PPIV1) and (SOV).

In the presence of non-neutralising maternally derived antibodies, intradermal and intramuscular vaccination with a modified live vaccine against porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) induce similar levels of neutralising antibodies or interferon-gamma secreting cells.

The purpose of this study was to compare the immune response generated by the intramuscular and the intradermal vaccination route against the porcine reproductive and respiratory syndrome virus (PRRSV). Piglets from a seronegative and a seropositive farm were selected (n = 28 piglets per farm), and each group was divided into two groups and vaccinated after weaning with modified live vaccine Unistrain® PRRS (Laboratorios Hipra Amer, Spain) by the intramuscular (IM) or the intradermic (ID) route. For the following 6 weeks, animals were weekly bled to assess the humoral response by PRRSV-specific antibody ELISA and viral neutralisation test.

Description of a New Clade within Subtype 1 of Causing Severe Outbreaks in Spain.

This report describes 28 genome sequences from a new clade within subtype 1 of , formerly known as porcine reproductive and respiratory syndrome virus 1. All share a potential recombinant pattern, with a highly pathogenic Italian strain as the putative major parental sequence and three other possible parents.

The use of a whole inactivated PRRS virus vaccine administered in sows and impact on maternally derived immunity and timing of PRRS virus infection in piglets.

Background: Porcine reproductive and respiratory syndrome virus (PRRSV) vaccination is usually based on administering periodically PRRS modified live virus (MLV) in sows throughout their life. Using this schedule, transfer of maternally derived antibodies to the offspring is limited. The aim of the present study was to test the concept of priming with an MLV and boosting with a commercial inactivated virus vaccine in sows to reduce PRRSV incidence and improve productivity.

Impact of Cryopreservation on Viability, Phenotype, and Functionality of Porcine PBMC.

The use of frozen peripheral blood mononuclear cells (PBMC) is common in immunological studies. The impact of freezing PBMC has been assessed using human and mice cells, but little information is available regarding domestic animals. In the present study, the phenotype and functionality of frozen porcine PBMC were examined.

Development of an antigen Enzyme-Linked AptaSorbent Assay (ELASA) for the detection of swine influenza virus in field samples.

Influenza viruses are highly variable pathogens that infect a wide range of mammalian and avian species. According to the internal conserved proteins (nucleoprotein: NP, and matrix proteins: M), these viruses are classified into type A, B, C, and D. Influenza A virus in swine is of significant importance to the industry since it is responsible for endemic infections that lead to high economic loses derived from poor weight gain, reproductive disorders, and the role it plays in Porcine Respiratory Disease Complex (PRDC).

Swine Dendritic Cell Response to Porcine Reproductive and Respiratory Syndrome Virus: An Update.

Dendritic cells (DCs) are the most potent antigen-presenting cells, unique to initiate and coordinate the adaptive immune response. In pigs, conventional DCs (cDCs), plasmacytoid DCs (pDCs), and monocyte-derived DCs (moDCs) have been described in blood and tissues. Different pathogens, such as viruses, could infect these cells, and in some cases, compromise their response.

Interaction of Type 1 Porcine Reproductive and Respiratory Syndrome Virus With Derived Conventional Dendritic Cells.

The present study delineates the interaction of a typical PRRSV1.1 isolate 3267 (moderate virulence) with derived pig conventional dendritic cells, cDC1, cDC2, and a CD14 population (designated as CD14 DCs). cDC1 and cDC2 were not susceptible to 3267 infection, but a fraction of CD14 DCs were infected.

Immune response does not prevent homologous Porcine epidemic diarrhoea virus reinfection five months after the initial challenge.

The aim of the present study was to evaluate the duration of protective immunity against Porcine epidemic diarrhoea virus (PEDV). To do so, a two phases study was performed. In the first phase, 75 four-week-old pigs (group A) were orally inoculated (0 days post-inoculation; dpi) with a European PEDV G1b strain and 14 were kept as controls (group B).

Porcine reproductive and respiratory syndrome virus impacts on gut microbiome in a strain virulence-dependent fashion.

Porcine reproductive and respiratory syndrome (PRRS) is a viral disease defined by reproductive problems, respiratory distress and a negative impact on growth rate and general condition. Virulent PRRS virus (PRRSV) strains have emerged in the last years with evident knowledge gaps in their impact on the host immune response. Thus, the present study examines the impact of acute PRRS virus (PRRSV) infection, with two strains of different virulence, on selected immune parameters and on the gut microbiota composition of infected pigs using 16S rRNA compositional sequencing.

Activation of regulated cell death in the lung of piglets infected with virulent PRRSV-1 Lena strain occurs earlier and mediated by cleaved Caspase-8.

PRRSV-1 virulent strains cause high fever, marked respiratory disease and severe lesions in lung and lymphoid organs. Regulated cell death (RCD), such as apoptosis, necroptosis and pyroptosis, is triggered by the host to interrupt viral replication eliminating infected cells, however, although it seems to play a central role in the immunopathogenesis of PRRSV, there are significant gaps regarding their sequence and activation upon PRRSV-infection. The present study evaluated RCD events by means of caspases expression in the lung of PRRSV-1-infected pigs and their impact on pulmonary macrophage subpopulations and lung lesion.

Biosecurity in pig farms: a review.

The perception of the importance of animal health and its relationship with biosecurity has increased in recent years with the emergence and re-emergence of several diseases difficult to control. This is particularly evident in the case of pig farming as shown by the recent episodes of African swine fever or porcine epidemic diarrhoea. Moreover, a better biosecurity may help to improve productivity and may contribute to reducing the use of antibiotics.

Development of Pig Conventional Dendritic Cells From Bone Marrow Hematopoietic Cells .

In recent years, porcine dendritic cells (DCs) have been identified from pig tissues. However, studying the interaction of porcine DCs with pathogens is still difficult due to the scarcity of DCs in tissues. In the present work, the Flt3-ligand (Flt3L)-based derivation system was further characterized and compared with other cytokine derivation models using a combination of factors: stem cell factor (SCF), GM-CSF, and IL-4.

Diversity of influenza A viruses retrieved from respiratory disease outbreaks and subclinically infected herds in Spain (2017-2019).

The present study was aimed to assess the diversity of influenza A viruses (IAV) circulating in pig farms in the Iberian Peninsula. The study included two different situations: farms suffering respiratory disease outbreaks compatible with IAV (n = 211) and randomly selected farms without overt respiratory disease (n = 19). Initially, the presence of IAV and lineage determination was assessed by qRT-PCR using nasal swabs.