Jean-François Valarcher
Swedish University of Agricultural Sciences
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Publication
Featured researches published by Jean-François Valarcher.
Emerging Infectious Diseases | 2005
Nick J. Knowles; Alan R. Samuel; Paul R. Davies; Rebecca J. Midgley; Jean-François Valarcher
The PanAsia strain is spreading explosively in Asia and extending to parts of Africa and Europe.
Emerging Infectious Diseases | 2009
Jean-François Valarcher; Nick J. Knowles; Valery Zakharov; Alexey Scherbakov; Zhidong Zhang; Youjun Shang; Zaixin Liu; Xiangtao Liu; Aniket Sanyal; Divakar Hemadri; C. Tosh; T. J. Rasool; Bramhadev Pattnaik; Kate R. Schumann; Tammy R. Beckham; Wilai Linchongsubongkoch; Nigel P. Ferris; Peter L. Roeder; David J. Paton
Viruses in 6 genetic groups have caused recent outbreaks in Asia.Emerging outbreaks of zoonotic diseases are affecting humans at an alarming rate. Until the ecological factors associated with zoonoses are better understood, disease emergence will continue. For Lyme disease, disease suppression has been demonstrated by a dilution effect, whereby increasing species diversity decreases disease prevalence in host populations. To test the dilution effect in another disease, we examined 17 ecological variables associated with prevalence of the directly transmitted Sin Nombre virus (genus Hantavirus, etiologic agent of hantavirus pulmonary syndrome) in its wildlife host, the deer mouse (Peromyscus maniculatus). Only species diversity was statistically linked to infection prevalence: as species diversity decreased, infection prevalence increased. The increase was moderate, but prevalence increased exponentially at low levels of diversity, a phenomenon described as zoonotic release. The results suggest that species diversity affects disease emergence.
Transboundary and Emerging Diseases | 2008
Jean-François Valarcher; Yves Leforban; Mark Rweyemamu; Peter Roeder; Guillaume Gerbier; David Mackay; Keith J. Sumption; David J. Paton; Nick J. Knowles
Foot-and-mouth disease (FMD) is one of the biggest threats to animal health in European countries. In the last 22 years (1985-2006), FMD has occurred 37 times in 14 European countries. Serotype O was most frequently involved in these outbreaks followed by A, C and Asia 1. Sometimes, epidemics were very limited and at other times, they were the cause of devastating economic losses. In most cases (22/37), the origin of the outbreaks could not be determined. For some of these outbreaks, however, routes of introduction and spread were identified through epidemiological inquiries. Moreover, in some cases, the origin of the virus was also traced by phylogenetic analysis of the partial or complete sequences of VP1 genes. Lessons learned from the outbreaks are still useful as most of the same risk factors persist. However, efforts made by FMD-free countries to help those where the disease is endemic are a valuable strategy for the reduction of the global risk. The present and the future potential sources of FMD infection need to be identified to best focus European efforts.
Virus Genes | 2008
Kate R. Schumann; Nick J. Knowles; Paul R. Davies; Rebecca J. Midgley; Jean-François Valarcher; Abdul Quader Raoufi; Thomas S. McKenna; William Hurtle; James P. Burans; Barbara M. Martin; Luis L. Rodriguez; Tammy R. Beckham
Foot-and-mouth disease virus (FMDV) isolates collected from various geographic locations in Afghanistan between 2003 and 2005 were genetically characterized, and their phylogeny was reconstructed utilizing nucleotide sequences of the complete VP1 coding region. Three serotypes of FMDV (types A, O, and Asia 1) were identified as causing clinical disease in Afghanistan during this period. Phylogenetic analysis revealed that the type A viruses were most closely related to isolates collected in Iran during 2002–2004. This is the first published report of serotype A in Afghanistan since 1975, therefore indicating the need for inclusion of serotype A in vaccine formulations that will be used to control disease outbreaks in this country. Serotype O virus isolates were closely related to PanAsia strains, including those that originated from Bhutan and Nepal during 2003–2004. The Asia 1 viruses, collected along the northern and eastern borders of Afghanistan, were most closely related to FMDV isolates collected in Pakistan during 2003 and 2004. Data obtained from this study provide valuable information on the FMDV serotypes circulating in Afghanistan and their genetic relationship with strains causing FMD in neighboring countries.
Veterinary Microbiology | 2009
Syseng Khounsy; James V. Conlan; Laurence J. Gleeson; H.A. Westbury; Axel Colling; David J. Paton; Nigel P. Ferris; Jean-François Valarcher; Jemma Wadsworth; Nick J. Knowles; Stuart D. Blacksell
Foot-and-mouth disease (FMD) causes sporadic disease outbreaks in the Lao Peoples Democratic Republic (Lao PDR) and appears to be endemic within a livestock population largely susceptible to infection. As Lao PDR is a major thoroughfare for transboundary animal movement, regular FMD outbreaks occur causing economic hardship for farmers and their families. The dominant serotype causing outbreaks between 1998 and 2006 was type O. Using phylogenetic analysis, type O isolated viruses were divided into two topotypes: South East Asia (SEA) and the Middle East-South Asia (ME-SA). Type A virus was reported only in 2003 and 2006 and type Asia 1 only in 1996 and 1998.
Vaccine | 2011
Sara Hägglund; Ke-Fei Hu; Karin Vargmar; Lesly Poré; Ann-Sophie Olofson; Krister Blodörn; Jenna Anderson; Parvin Ahooghalandari; John Pringle; Geraldine Taylor; Jean-François Valarcher
Abstract Bovine respiratory syncytial virus (BRSV) is a major cause of bronchiolitis and pneumonia in cattle and causes yearly outbreaks with high morbidity in Europe. Commercial vaccines against this virus needs improvement of efficacy, especially in calves with BRSV-specific maternally derived antibodies (MDA). We previously reported that an experimental BRSV-ISCOM vaccine, but not a commercial vaccine, induced strong clinical and virological protection in calves with MDA, immunized at 7–15 weeks of age. The aim of the present study was to characterize the immune responses, as well as to investigate the efficacy and safety in younger animals, representing the target population for vaccination. Four groups of five 3–8 week old calves with variable levels of BRSV-specific MDA were immunized s.c. twice at a 3 weeks interval with (i) BRSV immunostimulating complexes (BRSV-ISCOMs), (ii) BRSV-protein, (iii) adjuvant, or (iv) PBS. All calves were challenged with virulent BRSV by aerosol 2 weeks later and euthanized on day 6 after infection. The cellular and humoral responses were monitored as well as the clinical signs, the viral excretion and the pathology following challenge. Despite presence of MDA at the time of the immunization, only a minimum of clinical signs were observed in the BRSV-ISCOM group after challenge. In contrast, in all control groups, clinical signs of disease were observed in most of the animals (respiratory rates up to 76min−1 and rectal temperatures up to 41°C). The clinical protection was associated to a highly significant reduction of virus replication in the upper and lower respiratory tract of calves, rapid systemic and local antibody responses and T helper cell responses dominated by IFNγ production. Animals that did not shed virus detectable by PCR or cell culture following challenge possessed particularly high levels of pulmonary IgA. The protective immunological responses to BRSV proteins and the ability to overcome the inhibiting effect of MDA were dependent on ISCOM borne antigen presentation.
Veterinary Microbiology | 2015
Helena Back; Karin Ullman; Louise Treiberg Berndtsson; Miia Riihimäki; Johanna Penell; Karl Ståhl; Jean-François Valarcher; John Pringle
The equine gamma herpesviruses 2 and 5 (EHV-2 and -5) have frequently been observed in the equine population and until recently presumed low to nonpathogenic. However, recent reports linking presence of equine gamma herpesviruses with clinical signs of mild to severe lung disease, suggest that the role of these viruses in respiratory disease and poor performance syndrome is still unclear. Moreover, baseline data regarding the temporal pattern of shedding of EHV-2 and EHV-5 within stables and within individual actively racing horses have been lacking. In a prospective longitudinal study, we followed elite racing Standardbred trotters at monthly intervals for 13 months, to investigate whether the amount of EHV-2 and EHV-5 shedded in nasal secretions varied over time within and between individual horses. Sixty-six elite horses were investigated by analyzing nasal swabs and serum samples, a health check and evaluation of athletic performance monthly during the study period. Nasal swabs were analyzed with two newly developed qPCR assays for EHV-2 and EHV-5, respectively. Of 663 samples, 197 (30%) were positive for EHV-2 and 492 (74%) positive for EHV-5. Furthermore, 176 (27%) of the samples were positive for both EHV-2 and EHV-5 simultaneously. There was considerable variation in the amount and frequency of shedding of EHV-2 and EHV-5 within and between individual horses. Viral load varied seasonally, but neither EHV-2 nor EHV-5 viral peaks were associated with clinical respiratory disease and/or poor performance in racing Standardbred trotters.
Journal of General Virology | 2016
Helena Back; Karin Ullman; Mikael Leijon; Robert Söderlund; Johanna Penell; Karl Ståhl; John Pringle; Jean-François Valarcher
Equid herpesvirus 5 (EHV-5) is related to the human Epstein-Barr virus (human herpesvirus 4) and has frequently been observed in equine populations worldwide. EHV-5 was previously assumed to be low to non-pathogenic; however, studies have also related the virus to the severe lung disease equine multinodular pulmonary fibrosis (EMPF). Genetic information of EHV-5 is scanty: the whole genome was recently described and only limited nucleotide sequences are available. In this study, samples were taken twice 1 year apart from eight healthy horses at the same professional training yard and samples from a ninth horse that was diagnosed with EMPF with samples taken pre- and post-mortem to analyse partial glycoprotein B (gB) gene of EHV-5 by using next-generation sequencing. The analysis resulted in 27 partial gB gene sequences, 11 unique sequence types and five amino acid sequences. These sequences could be classified within four genotypes (I-IV) of the EHV-5 gB gene based on the degree of similarity of the nucleotide and amino acid sequences, and in this work horses were shown to be identified with up to three different genotypes simultaneously. The observations showed a range of interactions between EHV-5 and the host over time, where the same virus persists in some horses, whereas others have a more dynamic infection pattern including strains from different genotypes. This study provides insight into the genetic variation and dynamics of EHV-5, and highlights that further work is needed to understand the EHV-5 interaction with its host.
Journal of Veterinary Diagnostic Investigation | 2018
Gunilla Blomqvist; Karin Ullman; Thomas Segall; Elenor Hauzenberger; Lena Renström; Karin Persson-Waller; Mikael Leijon; Jean-François Valarcher
Species Pseudocowpox virus (PCPV; family Poxviridae) is known to cause pustular cutaneous disease in cattle. We describe an outbreak of pseudocowpox with an unusual clinical picture in a free-stall dairy herd of ~80 cows. Approximately 90% of the cows had vesicles, erosions, papules, and scabs on the vulva and vaginal mucosa. Histologic analysis of biopsy tissues indicated a primary, although not specified, viral infection. Transmission electron microscopy revealed parapoxvirus particles in both tissue and vesicular materials. Deep sequencing analysis of extracted DNA from swabbed vesicle areas gave a contig of nearly 120,000 nucleotides, matching the PCPV strain VR 634 with 100% identity. Analyses confirmed the absence of other potential causes of pustular vulvovaginitis such as bovine herpesvirus 1 and Ureaplasma diversum. A rolling cow brush was suspected to be the fomite.
Reproductive Biology | 2017
Metasu Chanrot; Gunilla Blomqvist; Yongzhi Guo; Karin Ullman; Mikael Juremalm; Renée Båge; Gaetano Donofrio; Jean-François Valarcher; P. Humblot
Bovine herpes virus type 4 (BoHV-4) can be transmitted by contaminated semen to cows at the time of breeding and may cause uterine disease. The aim of this study was to characterize the susceptibility of bovine endometrial epithelial cells (bEEC) to BoHV-4 by using an in vitro model. When bEEC were challenged with different multiplicity of infection (MOI; from 0.001 to 10) of BoHV-4 for 6days, a significant decrease in cell survival with increasing MOI was observed. The bEEC were subsequently challenged with BoHV-4 MOI 0.1 for 7days. During the first 4days, numbers increased in a similar way in controls and infected group (p<0.01 when compared to Day 0). After Day 4, numbers of live cells in infected samples decreased when compared to controls and were lower than control at Day 7 (p<0.01). From titration and qPCR, increasing number of viral particles was observed from Day 1, and reached a plateau at Day 5. Concentrations of IL-8 increased with time and were higher in supernatants from infected cells than in controls (p<0.0001). TNF-α concentrations presented similar profile as cell survival ones. In conclusion, the survival of bEEC was strongly impaired by BoHV-4 infection in a time and dose dependent manner and supernatant cytokine profiles were altered. This information supports BoHV-4 implication in clinical cases of uterine diseases and the existence of a risk of BoHV-4 transmission from infected males through animal breeding.