Porcine circovirus type 2 potentiates morbidity of Salmonella enterica serovar Choleraesuis in Cesarean-derived, colostrum-deprived pigs

Porcine Lawsonia intracellularis Ileitis in Italy and Its Association with Porcine Circovirus Type 2 (PCV2) Infection

The objective of this study was to employ a diagnostic algorithm, which involves detecting positive farms by stool PCR followed by PCR and histology/immunohistochemistry on ileum samples, for diagnosing Lawsonia intracellularis proliferative enteritis in Northern Italy. The primary aim was to examine the relationship between the gold standard of L. intracellularis diagnostics, namely histology and immunohistochemistry, and PCR in acute and chronic cases of L. intracellularis enteritides. An additional goal was to investigate the coinfection of L. intracellularis with porcine circovirus type 2 (PCV2). Twenty-eight ileum samples, including four from acute cases and 24 from chronic cases, were collected. PCR yielded positive results in 19 cases (four acute and 15 chronic cases). In comparison, immunohistochemistry was positive in 16 cases (four acute and 12 chronic cases), with an observed agreement of 89%. The findings suggest that performing the two tests in series can increase the specificity of the causal diagnosis. PCR may be used as a screening tool to identify the presence of the microorganism, and only positive cases will be examined by histology and immunohistochemistry to confirm the causative role of L. intracellularis. Co-infection with PCV2 was demonstrate in two out of four acute cases and in two out of 24 chronic cases, providing further evidence to support the hypothesis that when the infection starts with ubiquitous pathogens such as L. intracellularis, it may boost the possibility of PCV2 replication, especially in acute cases. As a result, this may trigger a transition from subclinical to clinical forms of PCV2 disease.

Genome-wide analysis of long non-coding RNA expression profile in porcine circovirus 2-infected intestinal porcine epithelial cell line by RNA sequencing

Porcine circovirus-associated disease (PCVAD), which is induced by porcine circovirus type 2 (PCV2), is responsible for severe economic losses. Recently, the role of noncoding RNAs, and in particular microRNAs, in PCV2 infection has received great attention. However, the role of long noncoding RNA (lncRNA) in PCV2 infection is unclear. Here, for the first time, we describe the expression profiles of lncRNAs in an intestinal porcine epithelial cell line (IPEC-J2) after PCV2 infection, and analyze the features of differently expressed lncRNAs and their potential target genes. After strict filtering of approximately 150 million reads, we identified 13,520 lncRNAs, including 199 lncRNAs that were differentially expressed in non-infected and PCV2-infected cells. Furthermore, trans analysis found lncRNA-regulated target genes enriched for specific Gene Ontology terms (P < 0.05), such as DNA binding, RNA binding, and transcription factor activity, which are closely associated with PCV2 infection. In addition, we analyzed the predicted target genes of differentially expressed lncRNAs, including SOD2, TNFAIP3, and ARG1, all of which are involved in infectious diseases. Our study identifies many candidate lncRNAs involved in PCV2 infection and provides new insight into the mechanisms underlying the pathogenesis of PCVAD.

[Detection of Salmonella Choleraesuis var. Kunzendorf in a fattening pig with septicaemic salmonellosis. A case report]

The present case reports the detection of Salmonella (S.) Choleraesuis var. Kunzendorf and porcine circovirus type 2 in an organic fattening pig suffering from septicaemic salmonellosis and porcine dermatitis and nephropathy syndrome. Six weeks after pigs had been housed in an organic fattening farm, an increase in mortality, diarrhea and coughing was observed. In recent years, S. choleraesuis var. Kunzendorf has been frequently detected in wild boars in Germany, whereas the same serovar did not play an important role in the Western European domestic pig population. A direct transmission of this serovar from wild boars to domestic pigs in this case could not be proven. However, because wild boars are important reservoirs for the spread of epizootic diseases to the domestic pig population, this case emphasises the importance of taking epidemiological relationships under consideration and to comply with biosecurity measures according to German law (Schweinehaltungshygieneverordnung).

Concurrent infections are important for expression of porcine circovirus associated disease

Porcine circovirus type 2 (PCV2) is the essential component of porcine circovirus disease (PCVD) as the disease syndrome is referred to in Europe and porcine circovirus associated disease (PCVAD) as it is referred to in North America. Singular PCV2 infection rarely results in clinical disease; however, PCVAD is often accelerated in onset, enhanced in severity and prolonged in duration by concurrent viral or bacterial infections. Due to its effect on the immune system, PCV2 has also been shown to enhance protozoal, metazoal, and fungal infections. Several retrospective or cross-sectional studies have investigated the presence and prevalence of various infectious agents associated with PCVAD under field conditions. Experimental models confirm that PCV2 replication and associated lesions can be enhanced by concurrent infection with other viruses or bacteria. The exact mechanisms by which concurrent pathogens upregulate PCV2 are unknown. Co-infections may promote PCV2 infection by increasing immune host cell replication and accumulation in tissues thereby enhancing targets for PCV2 replication. It has also been proposed that co-infections interfere with PCV2 clearance by alteration of cytokine production and profiles. The outcome of differences in timing of co-infections in PCV2-infected pigs is also likely very important and is an area where more research is needed. Given the current knowledge base, it is important that veterinarians do a thorough diagnostic investigation on herds where PCVAD is a recurrent problem in order to implement the most appropriate and cost effective intervention strategies.