title: Astrovirus as a possible cause of congenital tremor type AII in piglets?
abstract: BACKGROUND
  Congenital tremor is associated with demyelination of the brain and spinal cord and is clinically noted as outbreaks of trembling and shaking in newborn piglets during a limited time-period. Six forms of the disease have been described, where form AII may be caused by an, as yet, unidentified viral infection. This study aimed to investigate the presence of astrovirus and circovirus by sequencing and polymerase chain reaction (PCR) analysis and by relating the findings to the occurrence of disease and lesions in the brain, in 4-6 days-old piglets obtained from a clinical outbreak of congenital tremor.
  
  
  RESULTS
  In piglets with congenital tremor, there were mild to moderate vacuolar changes of the white matter in the cerebrum, brain stem and cerebellum. In healthy piglets, less conspicuous vacuolar changes were detected. One healthy and one diseased piglet were positive for porcine circovirus type 2. The nested pan-PCR showed the presence of astrovirus in at least one brain region in all piglets and by sequencing, two different porcine astrovirus lineages were identified.
  
  
  CONCLUSIONS
  The results do not support previous studies identifying porcine circovirus type 2 as the cause of congenital tremor. The demonstration of astrovirus in the brain of piglets suffering from congenital tremor is interesting. However, astrovirus was demonstrated in both healthy and diseased individuals and therefore, further studies are warranted to determine the possible involvement of astrovirus in the pathogenesis of congenital tremor in pigs.
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden. anne-lie.blomstrom@slu.se.
authors.forename: Anne-Lie
authors.initials: AL
authors.lastname: Blomström
authors.affiliation: Department of Biomedical Sciences and Veterinary Public Health, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden. cecilia.ley@slu.se.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Ley
authors.affiliation: Department of Clinical Sciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden. magdalena.jacobson@slu.se.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Jacobson
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000821:virology*; D019350:Astroviridae Infections / Q000151:congenital / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D001921:Brain / Q000473:pathology; D018173:Circoviridae Infections / Q000151:congenital / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D017925:Circovirus / Q000235:genetics / Q000302:isolation & purification; D001257:Mamastrovirus / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary; D017423:Sequence Analysis, RNA / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000151:congenital / Q000473:pathology / Q000821:virology*; D014202:Tremor / Q000151:congenital / Q000473:pathology / Q000662:veterinary*; D014764:Viral Proteins / Q000235:genetics
chemical_list: D014764:Viral Proteins