Application of a protocol for the diagnosis of postweaning multisystemic wasting syndrome in Italy

Abstract

Samples of superficial inguinal and bronchial lymph nodes, ileum, tonsil and lung were taken from three to five pigs on each of 61 farms with a clinical history of postweaning multisystemic wasting syndrome (PMWS). The samples were examined histologically and by immunohistochemistry for porcine circovirus type 2 (PCV-2). PMWS was diagnosed in two stages: first, an evaluation of the haematoxylin and eosin-stained sections that identified the cases in which the characteristic PCV-2 cytoplasmic inclusion bodies were apparent, and secondly, a conclusive step in which immunohistochemistry was applied to confirm PMWS in the cases in which there were positive immunohistochemical results that coincided with lesions indicative of PMWS in at least one of the lymphoid and/or lung tissues. The location of PCV-2 in specific lesions (cell depletion in lymphoid organs and interstitial pneumonia) confirmed PMWS in 45 of the 61 farms, 31 of which were also infected with porcine reproductive and respiratory syndrome virus. The lymphoid tissues were more reliable than the lungs for the diagnosis of PMWS, both in individual pigs and in groups of pigs, and farm diagnoses based on a group of pigs were more reliable than diagnoses based on single pigs.

Immunohistochemical Detection of Aetiological Agents of Proliferative and Necrotizing Pneumonia in Italian Pigs

“…Focal necrotizing bronchiolitis was present in four lungs, while 14 lungs had complicating bronchopneumonia. Twenty-two out of the 28 cases (78.6%) with PNP were pigs from farms confirmed as affected by PMWS (Sarli et al, 2009), whereas six were derived from farms unaffected by PMWS.…”

“…The study involved immunohistochemical assessment of samples of lung from 28 pigs with PNP. These affected animals were part of an investigation of porcine post-weaning multisystemic wasting syndrome (PMWS) on farms in northern and central Italy (Sarli et al, 2009). Only one of these pigs was SIV seropositive (unpublished data).…”

“…Serial sections (4 mm) for immunohistochemistry (IHC) were prepared from blocks of paraffin wax-embedded formalin-fixed tissue. Immunohistochemical labelling for PCV2 antigen was performed as described by Sarli et al (2009). Labelling for PRRSV antigen was performed by application of specific murine monoclonal antibody (clone SDOW 17-A, IgG1 isotype; Rural Technology Inc., Brookings, South Dakota) and labelling for ADV was also by murine monoclonal antibody (clone 2H6, IgG1 isotype; Grieco et al, 1997).…”

Porcine circovirus type 2 (PCV2) antigen localisation and post-weaning multisystemic wasting syndrome (PMWS) in free-ranging wild boar (Sus scrofa ssp scrofa) in Italy

“…The PCV2 host range is limited to the genus Sus (Segalés et al 2005) comprising both wild boar and domestic pigs. Serological surveys (Rose et al 2002), immunohistochemistry (IHC) (Ghebremariam and Gruys 2005;Sarli et al 2009) and in situ hybridization (ISH) (Ghebremariam and Gruys 2005) show that PCV2 is ubiquitous and may be encountered in herds both with and without PMWS. Wild boar (Sus scrofa ssp scrofa) can also be infected by PCV2 (Hungary, Cságola et al 2006;Belgium, Sanchez et al 2001;Slovenia, Toplak et al 2004;Spain, Vicente et al 2004;Germany, Knell et al 2005) and suffer from PMWS (Canada, Ellis et al 2003;Germany, Schulze et al 2004;Brasil, Correa et al 2006;Croatia, Lipej et al 2007; Greece, Sofia et al 2008).…”

Exploratory Epidemiological Study on Porcine Circovirus Type 2 Infection and Postweaning Multisystemic Wasting Syndrome in the Czech Republic

“…Pathological assessment of body condition shows that many of the pigs selected for necropsy were in terminal health condition and samples for microscopic examinations by IHC might be false negative. Recent studies have shown that the diagnosis of PMWS and other affections connected with PCV2 infections in pigs is more reliable when applied to larger groups of pigs (Sarli et al 2008).…”