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Studies of the molecular genetics and epidemiology of porcine rubulavirus infection

Cuevas Romero, Julieta Sandra (2015). Studies of the molecular genetics and epidemiology of porcine rubulavirus infection. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2015:51
ISBN 978-91-576-8300-7
eISBN 978-91-576-8301-4
[Doctoral thesis]

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Abstract

Porcine rubulavirus (PorPV) infection emerged spontaneously in pigs in Mexico in the early 1980s. Since the report of the initial outbreak of the disease, only one full-length genome from a strain isolated in 1984 (PorPV-LPMV/1984) has been sequenced. There is therefore limited information about the genetic variation of this virus. The overall objective of this thesis was to develop molecular techniques to help in the diagnostic field and to investigate in greater detail the full genomes of several isolates, and if possible, gain insights into the persistence, molecular epidemiology and the possible reservoirs of PorPV. In addition, a characterisation of the immune response during acute and persistent infection was included.

A real-time RT-PCR was developed for the detection of viral RNA from PorPV in clinical samples using TaqMan technology and primers for the P gene. This assay was highly sensitive (approximately 10 copies per reaction), specific, reproducible and a very useful tool for molecular diagnostics and for enabling studies of various aspects of PorPV throughout this thesis. RT-PCRs based on the NP and P genes were used to study the tissue distribution of the virus. Viral mRNA in the lymph nodes showed that the NP gene was consistently detected in the parotid, submaxilar, cervical and mesenteric nodes and the pancreas. Full-length genomes were sequenced from new isolates obtained from clinical cases of infected swine. The genetic comparison and phylogenetic analysis indicated that three different genetic variants of PorPV had spread in the swine population and that a new generation of circulating virus with a pronounced attenuation has begun to emerge in nature.

We also report the isolation of PorPV, or a related virus, from frugivorous, insectivorous, and hematophagous bats. A partial genome sequence analysis showed a 99.97 - 100% amino acid identity to the reference strain isolated from swine. However, larger parts of the genome must be sequenced to ascertain the genetic relationship between these viruses.

The study of the immune response during acute and persistent infection revealed enhanced levels of CD8+, CD4+ and CD2+ T-cells in all infected pigs at 10 days PI. CD8+ T-cell subpopulations were significantly higher (p<0.05) at 10 and 250 days PI, and CD4+ T-lymphocytes were also significant at 250 days PI.

In summary, this work developed molecular techniques that can be used to study the pathogenesis and molecular epidemiology of PorPV. The knowledge of the presence of different virus variants in nature, associated with a wildlife reservoir of PorPV can provide greater knowledge regarding the molecular genetic changes and useful data to establish new strategies in the control of this virus in Mexico.

Authors/Creators:Cuevas Romero, Julieta Sandra
Title:Studies of the molecular genetics and epidemiology of porcine rubulavirus infection
Alternative abstract:
LanguageAbstract
Spanish

Estudios de Epidemiología Molecular del Rubulavirus porcino

La infección del Rubulavirus porcino, se presenta como una nueva enfermedad de cerdos en Mexico a principios de los 80s. Este trabajo de investigación incluye el desarrollo de técnicas moleculares que permitieron realizar estudios relacionados a la persistencia del Rubulavirus porcino en cerdos naturalmente infectados, investigaciones sobre la epidemioloía molecular del virus en nuevos aislamientos y el estudio en bats como posibles reservorios del virus. Se concluye que el virus persiste en animals que se recuperan de una infección aguda y que el Rubulavirus porcino presenta mutaciones que originan la presencia de diferentes variantes genéticas con cierto grado de atenuación que actualmente circulan en las granjas de cerdos afectadas por esta infección. Así también se encuentran evidencias de la presencia de la circulación de este virus en murciélagos, como posibles reservorios.

Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :May 2015
Depositing date:16 April 2015
Volume:2015:51
Number of Pages:56
Papers/manuscripts:
NumberReferences
ISandra Cuevas-Romero, Anne-Lie Blomström, Arcelia Alvarado, Pablo Hernández-Jáuregui, Francisco Rivera-Benítez, Humberto Ramírez-Mendoza, Mikael Berg. (2013). Development of a real-time RT-PCR method for detection of Porcine rubulavirus (PorPV-LPMV). Journal of Virological Methods. 189, 1–6
IISandra Cuevas-Romero, E. Hernández-Baumgarten, S. Kennedy, P. Hernández-Jáuregui, M. Berg, J. Moreno-López. (2014). Long-term RNA persistence of Porcine rubulavirus (PorPV-LPMV) after an outbreak of a natural infection: The detection of viral mRNA in sentinel pigs suggests viral transmission. Virus Research 188, 155–161
IIISandra Cuevas, A. Rodríguez-Ropón, Seamus Kennedy, Jorge Moreno-López, Mikael Berg, Pablo Hernández-Jáuregui. (2009). Investigation of T-cell responses and viral mRNA persistence in lymph nodes of pigs infected with Porcine rubulavirus. Veterinary Immunology and Immunopathology 127, 148–152
Place of Publication:Uppsala
Publisher:Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8300-7
ISBN for electronic version:978-91-576-8301-4
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L73 Animal diseases
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 403 Veterinary Science > Medical Bioscience
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 403 Veterinary Science > Pathobiology
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 403 Veterinary Science > Clinical Science
Agrovoc terms:swine, chiroptera, paramyxoviridae, viroses, animal diseases, chronic course, immune response, infection, rna, genomes, genetic techniques, pcr
Keywords:Porcine rubulavirus, RNA, persistent infection, bays reservoir
URN:NBN:urn:nbn:se:slu:epsilon-e-2573
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-2573
ID Code:12126
Faculty:VH - Faculty of Veterinary Medicine and Animal Science
Department:(VH) > Dept. of Biomedical Sciences and Veterinary Public Health
Deposited By: PhD Julieta Sandra Cuevas-Romero
Deposited On:17 Apr 2015 10:14
Metadata Last Modified:22 Apr 2015 16:58

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