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- Stenberg, Hedvig, et al.
(author)
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A review of congenital tremor type A-II in piglets
- 2020
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In: Animal Health Research Reviews. - 1466-2523 .- 1475-2654. ; 21, s. 84-88
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Research review (peer-reviewed)abstract
- Congenital tremor (CT) is a neurological disease that affects new-born piglets. It was described in 1922 and six different forms, designated type AI-V and type B, are described based on the causative agents, as well as specific histological findings in the central nervous system (CNS). The various forms present with identical clinical signs consisting of mild to severe tremor of the head and body, sometimes complicated with ataxia. By definition, all A-forms have hypomyelination of the CNS, whereas there are no histopathological lesions with the B-form. The cause of the A-II form was long unknown, however, at present several different viruses have been proposed as the causative agent: porcine circovirus-II (PCV-II), astrovirus, PCV-like virus P1, and atypical porcine pestivirus (APPV). Currently, APPV is the only virus that has been proven to fulfill Mokili's Metagenomic Koch's Postulates. Following infection of the pregnant sow, the virus passes the placental barrier and infects the fetus. Interestingly, no clinical signs of disease have been associated with APPV in adult pigs. Furthermore, other viruses cannot be ruled out as additional potential causes of CT. Given the increased interest and research in CT type A-II, the aim of this review is to summarize current knowledge.
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| 2. |
- Stenberg, Hedvig, et al.
(author)
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Detection of atypical porcine pestivirus in Swedish piglets with congenital tremor type A-II
- 2020
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In: BMC Veterinary Research. - : Springer Science and Business Media LLC. - 1746-6148. ; 16
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Journal article (peer-reviewed)abstract
- BackgroundCongenital tremor (CT) type A-II is a neurological disorder characterized by tremor of the head and body of newborn piglets. The suggested causative agent of the disease is the recently found atypical porcine pestivirus (APPV). The virus has been detected in piglets suffering from congenital tremor in central Europe, South and North America and in China but no studies has so far been performed in the Nordic countries. The overarching goal of this study was to investigate if APPV is present in the brain tissue of Swedish piglets suffering from congenital tremor.From June 2017 - June 2018, 15 piglets from four Swedish farms with ongoing outbreaks of congenital tremor and 13 piglets with splay leg originating from four different farms, were investigated for presence of APPV RNA in brain tissue. Matched healthy control piglets (n=8) were also investigated. Two APPV-specific RT-qPCR methods targeting the NS3 and NS5B region, respectively, were used. A retrospective study was performed on material from Swedish piglets with congenital tremor sampled in 2004 (n=11) and 2011/2012 (n=3) using the described APPV-specific RT-qPCR methods. The total number of piglets with signs of CT in this study was 29.ResultsAtypical porcine pestivirus-RNA was detected in 93% (27/29) of the piglets suffering from congenital tremor. All piglets with congenital tremor from 2004 (n=11) and 2012 (n=3) were PCR-positive with respect to APPV, whereas, all of the healthy controls (n=11) were negative. The piglets with congenital tremor sampled 2017-2018 had an odds ratio of 91.8 (95% CI 3.9128 to 2153.7842, z=2.807, P=0.0050) to test positive for APPV by qRT-PCR compared to the healthy piglets (Fishers exact test p<0.0001). These findings make it interesting to continue investigating APPV in the Swedish pig-population.ConclusionThis is the first description of atypical porcine pestivirus in piglets suffering from congenital tremor type A-II in Sweden and the Nordic countries. The virus has been present in the Swedish pig population since at least 2004.
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