Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs with particular emphasis on the causative agent, the mode of transmission, the diagnostic tools and the control measures. A review

Abstract

Postweaning multisystemic wasting syndrome (PMWS) is a worldwide emerging disease of weaned piglets. The objective of this review is to summarize the current knowledge regarding PMWS, its causative agent, mode of transmission, diagnostic techniques to detect PCV-2, the possible control measures, and the association of PMWS and PCV-2 with porcine dermatitis and nephropathy syndrome (PDNS). The causative agent of PMWS is porcine circovirus type 2 (PCV-2), however, not all pigs infected with PCV-2 develop the syndrome. PCV-2 is consistently associated with PMWS and PMWS is considered not to occur without it. Both the syndrome and the virus are not regarded as new. Co-factors that could activate PCV-2 to cause PMWS are considered. This enigmatic nature of both the syndrome and the virus is triggering a concern towards uncertainties of the viral transmission, its introduction in to the herd, effective tools of diagnosis, and control strategies.

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

“…PCV2 has a mainly horizontal transmission (both direct and indirect) in the pig by oro-nasal secretions, faeces and urine (Ghebremariam and Gruys 2005), but a vertical transmission has also been described (Park et al 2005). The PCV2 host range is limited to the genus Sus (Segalés et al 2005) comprising both wild boar and domestic pigs.…”

“…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).…”

“…The concomitant presence of three disease characteristics, i.e. clinical signs and especially histological lesions, and PCV2 within the lesions (in lymphoid tissue and/or lung) are the hallmarks for PCVAD diagnosis (Ghebremariam and Gruys 2005;Sarli et al 2009;Segalés 2002;Sorden 2000). However, since clinical data in wild boar are usually not available, the diagnosis can only depend on pathological findings and demonstration of PCV2 within lesions (Schulze et al 2004).…”

“…The diagnosis of PMWS and PCVAD is hampered by numerous sub-clinical infections. Nowadays, IHC and ISH are considered the gold standard for detecting PCV2 as part of the diagnosis of PCVAD (Ghebremariam and Gruys 2005). The concomitant presence of three disease characteristics, i.e.…”

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

“…The high prevalence of the infection and the poor diagnostic indications from serology and PCR-related diseases make histological examinations essential for the diagnosis of PCV- 2-related diseases, to demonstrate the typical lesions and presence of the virus (capsid proteins or viral genome) in the lesions (Chae 2004, Ghebremariam and Gruys 2005, Segalés and others 2005). …”