The presence of six potentially pathogenic viruses in pigs suffering from post-weaning multisystemic wasting syndrome

Abstract

BackgroundPorcine circovirus type 2 (PCV2) is an etiological agent of porcine circovirus diseases (PCVDs). Post-weaning multisystemic wasting syndrome (PMWS) as the most important PCVD is considered a multifactorial disease. It was demonstrated that not only PCV2 but several viruses are associated with PMWS. Studies of viral co-infections in PMWS pigs led often to controversial results. The aim of this work was to determine the presence of emerging (PRRSV), re-emerging (PTV) and newly-emerging (TTSuV1, TTSuV2, PBoV1) viruses in samples of dead pigs suffering from PMWS. The impact of vaccination against PCV2 and the influence of age on the occurrence of single and multiple viral infections in pigs were also investigated.ResultsViruses were detected by PCR, RT-PCR and real-time PCR in the pooled tissue samples (lymph nodes, liver and spleen) of pigs with PMWS (n = 56) which were divided into three groups: suckling piglets, post-weaning pigs and fattening pigs. In addition, lymph node samples were collected from apparently healthy fattening pigs (n = 59). The effect of vaccination against PCV2 with Ingelvac CircoFlex vaccine was also investigated. Between non-vaccinated pigs, the highest prevalence of individual viruses and multiple viral infections were found in diseased post-weaning and fattening animals with PMWS. Severe clinical disease was observed in swine co-infected with PCV2 and PRRSV. The prevalence of TTSuV1 and TTSuV2 was high in all groups of pigs and did not appear to have a significant effect on the syndrome. Simultaneous infection with TTSuV1 and PBoV1 was frequently confirmed in pigs with PMWS. No healthy pig was found to be infected with PRRSV, PTV or PBoV1. Vaccination against PCV2 did not influence the prevalence of TTSuVs, but significantly protected pigs against multiple viral infections.ConclusionsPost-weaning PMWS pigs were more often co-infected with viral pathogens than suckling or fattening pigs. Co-infection with PRRSV enforces clinical signs of PMWS, the influence of other viral co-infections is not clear. Vaccination against PCV2 significantly reduced viral co-infections in pigs.

Molecular characterization of the ORF2 of Torque teno sus virus 1a and Torque teno sus virus 1b detected in cases of postweaning multisystemic wasting syndrome in Mexico

“…Nevertheless, Brazil (Teixeira et al., ), Cuba (Pérez et al., ) and Japan (Taira et al., ) showed prevalence values of 48%, 40% and 30%, respectively. Conversely, the data regarding TTSUV1b are even more contrasting, as Spain has reported a frequency of 91% (Kekarainen et al., ; Nieto et al., ) to 100% (Aramouni et al., ), consistent with the 94% reported in Sweden (Blömstrom et al., ) and 64% found in Great Britain (McMenamy et al., ) and Slovakia (Vlasakova et al., ). Such prevalence is considerably dissimilar to that found in a Mexican retrospective study in which lower frequencies of both Iotatorquevirus species than shown in other reports were found.…”

“…Additionally, porcine dermatitis and nephropathy syndrome (PDNS) was reproduced in PCV2‐negative pigs previously inoculated with TTSuV1a and porcine respiratory and reproductive syndrome virus (PRRSv; Krakowka & Ellis, ). In Europe, the TTSuV1a DNA prevalence has been high in serum, being 66%–76% in Spain (Kekarainen et al., ; Aramouni et al., ; Aramouni, Kekarainen, Ganges, Tarradas, & Segalés, ; Nieto, Aramouni, Grau‐Roma, Segalés, & Kekarainen, ), 77% in Sweden (Blömstrom et al., ) and 71.4% in Slovakia (Vlasakova, Leskova, Sliz, Jackova, & Vilcek, ), while in TTSuV1a, prevalence in fresh tissue samples was 41%–48% in Great Britain (McMenamy et al., ). Nevertheless, Brazil (Teixeira et al., ), Cuba (Pérez et al., ) and Japan (Taira et al., ) showed prevalence values of 48%, 40% and 30%, respectively.…”

Investigation of Porcine Circovirus type 2 (PCV2) antibodies in clinically healthy boars from Serbian commercial farms

“…of their genetic background (Opriessnig et al, 2008). Moreover, the fact that PCV2 needs one or more co-factors for the development of PCV2-SD (Lohse et al, 2008) make etiopathogenesis of PCV2 related diseases even more complex than previously assumed (Magar et al, 2000, Savić et al, 2010, Vlasakova et al, 2014.…”

Two novel porcine teschovirus strains as the causative agents of encephalomyelitis in the Netherlands

“…However, this virulent manifestation is now considered rare and only milder forms of neurologic disease associated with PTV-1 or other PTV serotypes have been reported in growing pigs in Canada, Spain and Brazil during the last years [2,5,8]. Although co-infections were not detected in these cases, immunosuppressive pathogens, such as porcine circovirus type 2 (PCV-2) and/or porcine reproductive and respiratory syndrome virus (PRRSV) could predispose animals to develop neurologic PTV disease [3,18]. It is therefore important to screen for immunosuppressive pathogens when PTV is suspected to be associated with neurologic signs.…”