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

Michaela Vlasakova,Stefan Vilcek,Valeria Leskova,Anna Jackova,Ivan Sliz

doi:10.1186/s12917-014-0221-8

Michaela Vlasakova, Stefan Vilcek + Show 3 more

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https://doi.org/10.1186/s12917-014-0221-8

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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.

Highlights

Porcine circovirus type 2 (PCV2) is an etiological agent of porcine circovirus diseases (PCVDs)
Evaluation of virus prevalence in each animal group Each of the five groups of pigs was evaluated on the basis of the following parameters: 1) Individual detection of six viral pathogens (PCV2, Porcine reproductive and respiratory syndrome virus (PRRSV), Torque teno sus virus 1 (TTSuV1), Torque teno sus virus 2 (TTSuV2), Porcine teschovirus (PTV) and Porcine bocavirus 1 (PBoV1)), 2) Prevalence of significant co-infections in each pig and each group and 3) Total number of viruses detected in each animal
No animal was found to be positive for TTSuV2 or PTV

Summary

Introduction

Porcine 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. Porcine circovirus type 2 (PCV2) as an etiological agent of porcine circovirus diseases (PCVDs) was firstly identified in the 1990s in Canada [1], and was later detected and characterized in USA and Europe [2,3]. In the Czech Republic and Slovakia PCV2 in pigs was confirmed and genetically typed a few years later [4,5,6]. Over the last five years, due to the world financial depression, weak government support of farmers and infectious diseases, the number of pigs in Slovakia has decreased dramatically while numbers in the Czech Republic have remained stable. Pigs are mostly imported from Denmark and Netherlands to both countries

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