SCiEntifiC REPORTS | 7: 16555 | DOI:10.1038/s41598-017-16407-0
ultrastructural evidence of
spontaneous Senecavirus A-induced
lesions at the choroid plexus of
Thalita E. S. Oliveira
, Mariana M. Z. Michelazzo
, Thiago Fernandes
, Admilton G. de
, Raquel A. Leme
, Alice F. Aleri
, Amauri A. Aleri
& Selwyn A. Headley
Epidemic Transient Neonatal Losses (ETNL) is a disease of piglets caused by Senecavirus A (SVA)
in which the method of dissemination and associated lesions are not well-dened. This study
investigated the possible SVA-induced lesions by examining spontaneous infections in newborn
piglets. Histopathology revealed ballooning degeneration of transitional epithelium, nonsuppurative
meningoencephalitis, plexus choroiditis, and atrophic enteritis. RT-PCR identied SVA in all tissues
evaluated and sequencing conrmed these results. Positive immunoreactivity to SVA was observed in
endothelial and epithelial tissues of all organs evaluated. Semithin analysis revealed vacuolization of
apical enterocytes of the small intestine, balloon degeneration and necrosis of endothelial cells of the
choroid plexus (CP) and nonsuppurative choroid plexitis. Ultrathin evaluation demonstrated hydropic
degeneration of apical enterocytes, degeneration and necrosis of endothelium of CP fenestrated
capillaries, degeneration of ependymocytes associated with intralesional viral particles. It is proposed
that SVA initially infects apical enterocytes of newborn piglets and probably enters the circulatory
system with entry to the brain via the CP, by rst producing an initial inammatory reaction, with
subsequent encephalitic dissemination. Consequently, SVA probably uses an enteric-neurological
method of dissemination.
Senecavirus A (SVA), formerly known as Seneca Valley virus, is the only representative of the genus Senecavirus,
. SVA is currently associated with the syndrome known as Epidemic Transient Neonatal
Losses (ETNL), which is clinically manifested by lethargy, cutaneous hyperaemia, diarrhoea, neurological signs
and/or sudden death in newborn piglets in pig farms from Brazil
, North American
. Furthermore, ETNL was reported as aecting piglets under 10 days of age
. Piglet mortality due to
SVA in Brazil has been estimated as 20–30% in the states of Paraná and Santa Catarina
, and 30–70% in the states
of Minas Gerais and Goiás
. Additionally, in Brazil the disease in piglets and sows occur simultaneously
Laboratory of Animal Pathology, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina,
P.O. Box 10011, 86057-970, Londrina, Paraná, Brazil.
Laboratory of Electron Microscopy and Microanalysis, Central
of Multi-User Research Laboratories, Universidade Estadual de Londrina, Londrina, Paraná, Brazil.
Microbial Biotechnology, Department of Microbiology, Universidade Estadual de Londrina, Londrina, Paraná, Brazil.
Laboratory of Animal Virology, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina,
Londrina, Paraná, Brazil.
Molecular Biology Unit, Multi-User Animal Health Laboratory, Department of Veterinary
Preventive Medicine, Universidade Estadual de Londrina, Londrina, Paraná, Brazil.
Tissue Processing Unit, Multi-
User Animal Health Laboratory, Department of Veterinary Preventive Medicine, Universidade Estadual de Londrina,
Londrina, Paraná, Brazil. Correspondence and requests for materials should be addressed to S.A.H. (email: selwyn.
Received: 16 August 2017
Accepted: 12 November 2017
Published: xx xx xxxx