Porcine Lawsonia intracellularis Ileitis in Italy and Its Association with Porcine Circovirus Type 2 (PCV2) Infection
Author:
D’Annunzio Giulia12ORCID, Ostanello Fabio1ORCID, Muscatello Luisa Vera1ORCID, Orioles Massimo3ORCID, Bacci Barbara1, Jacumin Niccolò4, Leotti Giorgio4, Tommasini Nicola4, Alborali Giovanni Loris2, Luppi Andrea2ORCID, Vio Denis5, Mandrioli Luciana1ORCID, Sarli Giuseppe1ORCID
Affiliation:
1. Dipartimento di Scienze Mediche Veterinarie, Università di Bologna, 40126 Bologna, Italy 2. Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, 25124 Brescia, Italy 3. Dipartimento di Scienze Agroalimentari, Ambientali e Animali, 33100 Udine, Italy 4. Boehringer Ingelheim Animal Health Italia SpA, 20139 Milano, Italy 5. Istituto Zooprofilattico Sperimentale delle Venezie, 33030 Udine, Italy
Abstract
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.
Subject
General Veterinary,Animal Science and Zoology
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