Investigation of chronic and persistent classical swine fever infections under field conditions and their impact on vaccine efficacy
Coronado, Liani (National Centre for Animal and Plant Health (CENSA). OIE Collaborating Centre for Disaster Risk Reduction in Animal Health)
Bohórquez Garzón, José Alejandro (Institut de Recerca i Tecnologia Agroalimentàries. Centre de Recerca en Sanitat Animal)
Muñoz González, Sara (Institut de Recerca i Tecnologia Agroalimentàries. Centre de Recerca en Sanitat Animal)
Pérez, Lester Josue (University of Illinois. College of Veterinary Science. Department of Clinical Veterinary Medicine)
Rosell, Rosa (Institut de Recerca i Tecnologia Agroalimentàries. Centre de Recerca en Sanitat Animal)
Fonseca, Osvaldo (National Centre for Animal and Plant Health (CENSA). OIE Collaborating Centre for Disaster Risk Reduction in Animal Health)
Delgado, Laiyen (National Centre for Animal and Plant Health (CENSA). OIE Collaborating Centre for Disaster Risk Reduction in Animal Health)
Perera, Carmen Laura (National Centre for Animal and Plant Health (CENSA). OIE Collaborating Centre for Disaster Risk Reduction in Animal Health)
Frías, María Teresa (National Centre for Animal and Plant Health (CENSA). OIE Collaborating Centre for Disaster Risk Reduction in Animal Health)
Ganges, Llilianne (Institut de Recerca i Tecnologia Agroalimentàries. Centre de Recerca en Sanitat Animal)

Fecha:	2019
Resumen:	Background: Recent studies have hypothesized that circulation of classical swine fever virus (CSFV) variants when the immunity induced by the vaccine is not sterilizing might favour viral persistence. Likewise, in addition to congenital viral persistence, CSFV has also been proven to generate postnatal viral persistence. Under experimental conditions, postnatal persistently infected pigs were unable to elicit a specific immune response to a CSFV live attenuated vaccine via the mechanism known as superinfection exclusion (SIE). Here, we study whether subclinical forms of classical swine fever (CSF) may be present in a conventional farm in an endemic country and evaluate vaccine efficacy under these types of infections in field conditions. Results: Six litters born from CSF-vaccinated gilts were randomly chosen from a commercial Cuban farm at 33 days of age (weaning). At this time, the piglets were vaccinated with a lapinized live attenuated CSFV C-strain vaccine. Virological and immunological analyses were performed before and after vaccination. The piglets were clinically healthy at weaning; however, 82% were viraemic, and the rectal swabs in most of the remaining 18% were positive. Only five piglets from one litter showed a specific antibody response. The tonsils and rectal swabs of five sows were CSFV positive, and only one of the sows showed an antibody response. After vaccination, 98% of the piglets were unable to clear the virus and to seroconvert, and some of the piglets showed polyarthritis and wasting after 36 days post vaccination. The CSFV E2 glycoprotein sequences recovered from one pig per litter were the same. The amino acid positions 72(R), 20(L) and 195(N) of E2 were identified in silico as positions associated with adaptive advantage. Conclusions: Circulation of chronic and persistent CSF infections was demonstrated in field conditions under a vaccination programme. Persistent infection was predominant. Here, we provide evidence that, in field conditions, subclinical infections are not detected by clinical diagnosis and, despite being infected with CSFV, the animals are vaccinated, rather than diagnosed and eliminated. These animals are refractory to vaccination, likely due to the SIE phenomenon. Improvement of vaccination strategies and diagnosis of subclinical forms of CSF is imperative for CSF eradication.
Ayudas:	Ministerio de Ciencia e Innovación RTI2018-100887-B-100 Ministerio de Economía y Competitividad AGL2015-66907
Nota:	This research was supported by Program I.1: Research grants for and about development from the MAEC-AECID programme of the Spanish government and by grants AGL2015-66907 and RTI2018-100887-B-100 from the Spanish government; the CERCA Programme, Generalitat de Catalunya, is also acknowledged for funding this research. The funding bodies did not play a role in the design of the study; collection, analysis, and interpretation of the data; or writing of the manuscript.
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	CSFV ; Chronic infection ; Persistent infection ; Vaccination failures ; Viral evolution
Publicado en:	BMC veterinary research, Vol. 15 Núm. 1 (July 2019) , p. 247, ISSN 1746-6148

DOI: 10.1186/s12917-019-1982-x
PMID: 31307464

13 p, 1.9 MB

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Documentos de investigación > Documentos de los grupos de investigación de la UAB > Centros y grupos de investigación (producción científica) > Ciencias de la salud y biociencias > Centre de Recerca en Sanitat Animal (CReSA-IRTA)
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