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1.
Transbound Emerg Dis ; 66(5): 2025-2032, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31127981

RESUMO

Lagoviruses are an essential tool for managing wild rabbit populations in Australia. Our understanding of lagovirus epidemiology in Australia currently depends on members of the public submitting liver samples from dead lagomorphs (i.e. rabbits and hares) through a monitoring program called Rabbitscan. However, many wild lagomorphs die in inaccessible locations or are scavenged before sampling can occur, leading to considerable sampling bias. In this study, we screened field-caught carrion flies for the presence of lagoviruses to monitor virus circulation patterns in the landscape, with an aim to establish a less biased epidemiological surveillance tool. Carrion flies were collected from two study sites over a 22-month period and these samples were used to optimize and validate molecular testing methods in this sample type for the currently circulating lagovirus variants. Virus was clearly detectable in field-caught carrion flies using optimized SYBR-green RT-qPCR and RT-PCR assays. However, variant identification was frequently hindered by the low virus loads present in carrion fly samples and spurious RT-PCR amplification. This was overcome by frequent sampling, which effectively acts as replicate sampling to verify inconclusive results. There was generally good correlation between virus detections and variant identification in carrion flies and in samples recovered from wild lagomorphs. The methods reported here provide an additional surveillance tool to monitor lagovirus spread and circulation at a landscape scale, which in turn can help to guide more effective rabbit management programs.


Assuntos
Infecções por Caliciviridae/epidemiologia , Dípteros/virologia , Lebres/virologia , Lagovirus/isolamento & purificação , Espécies Sentinelas , Animais , Austrália/epidemiologia , Infecções por Caliciviridae/virologia , Monitoramento Epidemiológico , Vírus da Doença Hemorrágica de Coelhos/genética , Coelhos , Reação em Cadeia da Polimerase em Tempo Real
2.
Arch Virol ; 164(1): 279-283, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30284631

RESUMO

Rabbit hemorrhagic disease virus (RHDV) is highly lethal to the European rabbit (Oryctolagus cuniculus). It was first reported in 1984 in China, but in 2010, a new variant of the virus was detected (GI.2) in France. Several recombination events with pathogenic and non-pathogenic strains have been described. Here, we report the first sequences of RHDV in Africa, isolated from Moroccan rabbits, and these resemble GI.1b/GI.1b/GI.2 recombinants found in the Iberian Peninsula. Monitoring and characterization of strains from future outbreaks are advised to guarantee the success of current programs on small-rabbit production for poverty alleviation in African countries.


Assuntos
Infecções por Caliciviridae/veterinária , Lagovirus/genética , Lagovirus/isolamento & purificação , Coelhos/virologia , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Marrocos/epidemiologia , Filogenia
3.
BMC Vet Res ; 14(1): 367, 2018 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-30477499

RESUMO

BACKGROUND: Prior to 2010, the lagoviruses that cause rabbit hemorrhagic disease (RHD) in European rabbits (Oryctolagus cuniculus) and European brown hare syndrome (EBHS) in hares (Lepus spp.) were generally genus-specific. However, in 2010, rabbit hemorrhagic disease virus 2 (RHDV2), also known as Lagovirus europaeus GI.2, emerged and had the distinguishing ability to cause disease in both rabbits and certain hare species. The mountain hare (Lepus timidus) is native to Sweden and is susceptible to European brown hare syndrome virus (EBHSV), also called Lagovirus europaeus GII.1. While most mountain hare populations are found on the mainland, isolated populations also exist on islands. Here we investigate a mortality event in mountain hares on the small island of Hallands Väderö where other leporid species, including rabbits, are absent. RESULTS: Post-mortem and microscopic examination of three mountain hare carcasses collected from early November 2016 to mid-March 2017 revealed acute hepatic necrosis consistent with pathogenic lagovirus infection. Using immunohistochemistry, lagoviral capsid antigen was visualized within lesions, both in hepatocytes and macrophages. Genotyping and immunotyping of the virus independently confirmed infection with L. europaeus GI.2, not GII.1. Phylogenetic analyses of the vp60 gene grouped mountain hare strains together with a rabbit strain from an outbreak of GI.2 in July 2016, collected approximately 50 km away on the mainland. CONCLUSIONS: This is the first documented infection of GI.2 in mountain hares and further expands the host range of GI.2. Lesions and tissue distribution mimic those of GII.1 in mountain hares. The virus was most likely initially introduced from a concurrent, large-scale GI.2 outbreak in rabbits on the adjacent mainland, providing another example of how readily this virus can spread. The mortality event in mountain hares lasted for at least 4.5 months in the absence of rabbits, which would have required virus circulation among mountain hares, environmental persistence and/or multiple introductions. This marks the fourth Lepus species that can succumb to GI.2 infection, suggesting that susceptibility to GI.2 may be common in Lepus species. Measures to minimize the spread of GI.2 to vulnerable Lepus populations therefore are prudent.


Assuntos
Infecções por Caliciviridae/veterinária , Lebres , Lagovirus , Animais , Animais Selvagens , Infecções por Caliciviridae/mortalidade , Infecções por Caliciviridae/patologia , Surtos de Doenças/veterinária , Feminino , Lagovirus/classificação , Lagovirus/isolamento & purificação , Masculino , Tipagem Molecular , Filogenia , Sorotipagem/veterinária , Suécia
4.
J Virol ; 92(4)2018 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-29187537

RESUMO

Rabbit hemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV) are two lagoviruses from the family Caliciviridae that cause fatal diseases in two leporid genera, Oryctolagus and Lepus, respectively. In the last few years, several examples of host jumps of lagoviruses among leporids were recorded. In addition, a new pathogenic genotype of RHDV emerged, and many nonpathogenic strains of lagoviruses have been described. The molecular mechanisms behind host shifts and the emergence of virulence are unknown. Since RHDV uses glycans of the histo-blood group antigen type as attachment factors to initiate infection, we studied if glycan specificities of the new pathogenic RHDV genotype, nonpathogenic lagoviruses, and EBHSV potentially play a role in determining the host range and virulence of lagoviruses. We observed binding to A, B, or H antigens of the histo-blood group family for all strains known to primarily infect European rabbits (Oryctolagus cuniculus), which have recently been classified as GI strains. However, we could not explain the emergence of virulence, since similar glycan specificities were found in several pathogenic and nonpathogenic strains. In contrast, EBHSV, recently classified as GII.1, bound to terminal ß-linked N-acetylglucosamine residues of O-glycans. Expression of these attachment factors in the upper respiratory and digestive tracts in three lagomorph species (Oryctolagus cuniculus, Lepus europaeus, and Sylvilagus floridanus) showed species-specific patterns regarding susceptibility to infection by these viruses, indicating that species-specific glycan expression is likely a major contributor to lagovirus host specificity and range.IMPORTANCE Lagoviruses constitute a genus of the family Caliciviridae comprising highly pathogenic viruses, RHDV and EBHSV, that infect rabbits and hares, respectively. Recently, nonpathogenic strains were discovered and new pathogenic strains have emerged. In addition, host jumps between lagomorphs have been observed. The mechanisms responsible for the emergence of pathogenicity and host species range are unknown. Previous studies showed that RHDV strains attach to glycans expressed in the upper respiratory and digestive tracts of rabbits, the likely portals of virus entry. Here, we studied the glycan-binding properties of novel pathogenic and nonpathogenic strains looking for a link between glycan binding and virulence or between glycan specificity and host range. We found that glycan binding did not correlate with virulence. However, expression of glycan motifs in the upper respiratory and digestive tracts of lagomorphs revealed species-specific patterns associated with the host ranges of the virus strains, suggesting that glycan diversity contributes to lagovirus host ranges.


Assuntos
Infecções por Caliciviridae/virologia , Vírus da Doença Hemorrágica de Coelhos/fisiologia , Lagomorpha/virologia , Lagovirus/fisiologia , Polissacarídeos/metabolismo , Virulência , Ligação Viral , Animais , Infecções por Caliciviridae/metabolismo , Suscetibilidade a Doenças , Lebres , Lagomorpha/classificação , Lagomorpha/metabolismo , Filogenia , Coelhos , Especificidade da Espécie
5.
Res Vet Sci ; 117: 81-84, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29195228

RESUMO

European brown hare syndrome virus (EBHSV) was detected in a faecal swab collected from a wolf carcass in Northern Italy. The full-length genome of the EBHSV WOLF/17/2016/ITA strain was determined. In the VP60 capsid gene, the wolf strain displayed the highest genetic identity (99.2-99.1% nucleotide and 99.6-99.7% amino acid) with two EBHSV strains recently found in the intestinal content of a red fox and in the spleen and liver of a hare in Northern Italy. This finding poses interrogatives on the potential role of carnivores as EBHSV passive carriers, favoring the introduction and spread of the virus among different hare populations.


Assuntos
Infecções por Caliciviridae/veterinária , Lebres/virologia , Lagovirus/isolamento & purificação , Lobos/virologia , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/transmissão , Fezes/virologia , Itália/epidemiologia
6.
Vet Res ; 48(1): 70, 2017 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-29080562

RESUMO

Rabbit haemorrhagic disease virus (RHDV) is a lagovirus that causes rabbit haemorrhagic disease (RHD) in European rabbits (Oryctolagus cuniculus). In 2010, a new genotype called RHDV2 emerged in France. It exhibits a larger host range than classical RHDV strains by sporadically infecting different hare species, including the European hare (Lepus europaeus). Phylogenetic analyses revealed that closely related RHDV2 strains circulate locally in both hares and rabbits, and therefore that RHDV2 strains infecting hares do not belong to a lineage that has evolved only in this species. We showed that RHDV2 is widely distributed in France and that it was responsible for more than a third of cases of lagovirus disease in European hare populations in 2015. The oldest RHDV2 positive hare was sampled in November 2013 and we reported two hares co-infected by EBHSV and RHDV2. All together, our results raise important epidemiological and evolutionary issues. In particular, along with the potential emergence of recombinant EBHSV/RHDV2 strains in hares, the enlargement of the host range changes the host population structure of RHDV2 and may alter the impact of the virus on rabbit and hare populations.


Assuntos
Infecções por Caliciviridae/veterinária , Surtos de Doenças/veterinária , Lebres , Vírus da Doença Hemorrágica de Coelhos/genética , Lagovirus/genética , Coelhos , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , França/epidemiologia , Genótipo , Fígado/virologia , Epidemiologia Molecular , Filogenia , Prevalência
7.
J Gen Virol ; 98(7): 1658-1666, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28714849

RESUMO

Lagoviruses belong to the Caliciviridae family. They were first recognized as highly pathogenic viruses of the European rabbit (Oryctolagus cuniculus) and European brown hare (Lepus europaeus) that emerged in the 1970-1980s, namely, rabbit haemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV), according to the host species from which they had been first detected. However, the diversity of lagoviruses has recently expanded to include new related viruses with varying pathogenicity, geographic distribution and host ranges. Together with the frequent recombination observed amongst circulating viruses, there is a clear need to establish precise guidelines for classifying and naming lagovirus strains. Therefore, here we propose a new nomenclature based on phylogenetic relationships. In this new nomenclature, a single species of lagovirus would be recognized and called Lagovirus europaeus. The species would be divided into two genogroups that correspond to RHDV- and EBHSV-related viruses, respectively. Genogroups could be subdivided into genotypes, which could themselves be subdivided into phylogenetically well-supported variants. Based on available sequences, pairwise distance cutoffs have been defined, but with the accumulation of new sequences these cutoffs may need to be revised. We propose that an international working group could coordinate the nomenclature of lagoviruses and any proposals for revision.


Assuntos
Lagovirus/classificação , RNA Viral/genética , Terminologia como Assunto , Animais , Infecções por Caliciviridae/virologia , Genótipo , Lebres , Lagovirus/genética , Lagovirus/patogenicidade , Filogenia , Coelhos
8.
J Gen Virol ; 98(1): 68-76, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27902397

RESUMO

Vesivirus 2117 is an adventitious agent that, in 2009, was identified as a contaminant of Chinese hamster ovary cells propagated in bioreactors at a pharmaceutical manufacturing plant belonging to Genzyme. The consequent interruption in supply of Fabrazyme and Cerezyme (drugs used to treat Fabry and Gaucher diseases, respectively) caused significant economic losses. Vesivirus 2117 is a member of the Caliciviridae, a family of small icosahedral viruses encoding a positive-sense RNA genome. We have used cryo-electron microscopy and three-dimensional image reconstruction to calculate a structure of vesivirus 2117 virus-like particles as well as feline calicivirus and a chimeric sapovirus. We present a structural comparison of several members of the Caliciviridae, showing that the distal P domain of vesivirus 2117 is morphologically distinct from that seen in other known vesivirus structures. Furthermore, at intermediate resolutions, we found a high level of structural similarity between vesivirus 2117 and Caliciviridae from other genera: sapovirus and rabbit hemorrhagic disease virus. Phylogenetic analysis confirms vesivirus 2117 as a vesivirus closely related to canine vesiviruses. We postulate that morphological differences in virion structure seen between vesivirus clades may reflect differences in receptor usage.


Assuntos
Capsídeo/ultraestrutura , Lagovirus/ultraestrutura , Sapovirus/ultraestrutura , Vesivirus/ultraestrutura , Animais , Cricetulus , Microscopia Crioeletrônica , Imageamento Tridimensional , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Vesivirus/genética
10.
Vet Res ; 46: 106, 2015 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-26403184

RESUMO

In 2010 a new Lagovirus related to rabbit haemorrhagic disease virus (RHDV) emerged in France and has since rapidly spread throughout domestic and wild rabbit populations of several European countries. The new virus, termed RHDV2, exhibits distinctive genetic, antigenic and pathogenic features. Notably, RHDV2 kills rabbits previously vaccinated with RHDV vaccines. Here we report for the first time the generation and characterization of RHDV2-specific virus-like particles (VLPs). Our results further confirmed the differential antigenic properties exhibited by RHDV and RHDV2, highlighting the need of using RHDV2-specific diagnostic assays to monitor the spread of this new virus.


Assuntos
Antígenos Virais/imunologia , Infecções por Caliciviridae/veterinária , Lagovirus/imunologia , Coelhos , Animais , Infecções por Caliciviridae/imunologia , Infecções por Caliciviridae/virologia , Vírus da Doença Hemorrágica de Coelhos/genética , Vírus da Doença Hemorrágica de Coelhos/imunologia , Lagovirus/genética , Filogenia , Análise de Sequência de DNA/veterinária
11.
Vet Res ; 46: 13, 2015 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-25828691

RESUMO

The eastern cottontail (Sylvilagus floridanus) is an American lagomorph. In 1966, it was introduced to Italy, where it is currently widespread. Its ecological niche is similar to those of native rabbits and hares and increasing overlap in distribution brings these species into ever closer contact. Therefore, cottontails are at risk of infection with the two lagoviruses endemically present in Italy: Rabbit Haemorrhagic Disease virus (RHDV) and European Brown Hare Syndrome Virus (EBHSV). To verify the susceptibility of Sylvilagus to these viruses, we analyzed 471 sera and 108 individuals from cottontail populations in 9 provinces of north-central Italy from 1999 to 2012. In total, 15-20% of the cottontails tested seropositive for EBHSV; most titres were low, but some were as high as 1/1280. All the cottontails virologically tested for RHDV and EBHSV were negative with the exception of one individual found dead with hares during a natural EBHS outbreak in December 2009. The cottontail and the hares showed typical EBHS lesions, and the EBHSV strain identified was the same in both species (99.9% identity). To experimentally confirm the diagnosis, we performed two trials in which we infected cottontails with both EBHSV and RHDV. One out of four cottontails infected with EBHSV died of an EBHS-like disease, and the three surviving animals developed high EBHSV antibody titres. In contrast, neither mortality nor seroconversion was detected after infection with RHDV. Taken together, these results suggest that Sylvilagus is susceptible to EBHSV infection, which occasionally evolves to EBHS-like disease; the eastern cottontail could therefore be considered a "spill over" or "dead end" host for EBHSV unless further evidence is found to confirm that it plays an active role in the epidemiology of EBHSV.


Assuntos
Infecções por Caliciviridae/veterinária , Surtos de Doenças/veterinária , Lagomorpha , Lagovirus/isolamento & purificação , Animais , Anticorpos Antivirais/sangue , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/transmissão , Infecções por Caliciviridae/virologia , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Vírus da Doença Hemorrágica de Coelhos/isolamento & purificação , Espécies Introduzidas , Itália/epidemiologia , Masculino , Estações do Ano
12.
Virology ; 468-470: 104-112, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25155199

RESUMO

European brown hare syndrome virus (EBHSV) is the aetiological agent of European brown hare syndrome (EBHS), a disease affecting Lepus europaeus and Lepus timidus first diagnosed in Sweden in 1980. To characterize EBHSV evolution we studied hare samples collected in Sweden between 1982 and 2008. Our molecular clock dating is compatible with EBHSV emergence in the 1970s. Phylogenetic analysis revealed two lineages: Group A persisted until 1989 when it apparently suffered extinction; Group B emerged in the mid-1980s and contains the most recent strains. Antigenic differences exist between groups, with loss of reactivity of some MAbs over time, which are associated with amino acid substitutions in recognized epitopes. A role for immune selection is also supported by the presence of positively selected codons in exposed regions of the capsid. Hence, EBHSV evolution is characterized by replacement of Group A by Group B viruses, suggesting that the latter possess a selective advantage.


Assuntos
Antígenos Virais/metabolismo , Evolução Molecular , Variação Genética , Lagovirus/genética , Animais , Anticorpos Monoclonais , Anticorpos Antivirais , Antígenos Virais/genética , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/veterinária , Infecções por Bunyaviridae/virologia , Epitopos/genética , Regulação Viral da Expressão Gênica/fisiologia , Lebres/virologia , Fígado/virologia , Modelos Moleculares , Filogenia , Conformação Proteica , Suécia/epidemiologia , Fatores de Tempo
13.
Pol J Vet Sci ; 17(2): 353-5, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24988863

RESUMO

In this paper we describe recently occurring outbreaks of European brown hare syndrome (EBHS) in a captive hare population. The aim of our study was to evaluate the phylogenetic position of detected Polish strains compared to other European strains of EBHSV. Investigations were undertaken in hares from different provinces of Poland. Liver or spleen samples were tested for viral RNA using the RT-nested PCR method and the products were subsequently sequenced. The genetic analysis was based on the fragment of gene encoding viral capsid protein; it revealed a high homology and close relationship between Polish and European EBHSV strains isolated between 2001 and 2011.


Assuntos
Infecções por Bunyaviridae/veterinária , Lebres , Lagovirus/genética , Animais , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/virologia , Lagovirus/isolamento & purificação , Filogenia , Polônia/epidemiologia
14.
PLoS One ; 8(9): e74360, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24069299

RESUMO

A study was conducted in order to determine the occurrence of European Brown Hare Syndrome virus (EBHSV) in Denmark and possible relation between disease pathogenesis and Major Histocompatibility Complex (MHC) host genotype. Liver samples were examined from 170 brown hares (hunted, found sick or dead), collected between 2004 and 2009. Macroscopical and histopathological findings consistent with EBHS were detected in 24 (14.1%) hares; 35 (20.6%) had liver lesions not typical of the syndrome, 50 (29.4%) had lesions in other tissues and 61 (35.9%) had no lesions. Sixty five (38.2%) of 170 samples were found to be EBHSV-positive (RT-PCR, VP60 gene). In order to investigate associations between viral pathogenesis and host genotype, variation within the exon 2 DQA gene of MHC was assessed. DQA exon 2 analysis revealed the occurrence of seven different alleles in Denmark. Consistent with other populations examined so far in Europe, observed heterozygosity of DQA (H o = 0.1180) was lower than expected (H e = 0.5835). The overall variation for both nucleotide and amino acid differences (2.9% and 14.9%, respectively) were lower in Denmark than those assessed in other European countries (8.3% and 16.9%, respectively). Within the peptide binding region codons the number of nonsynonymous substitutions (dN) was much higher than synonymous substitutions (dS), which would be expected for MHC alleles under balancing selection. Allele frequencies did not significantly differ between EBHSV-positive and -negative hares. However, allele Leeu-DQA*30 was detected in significantly higher (P = 0.000006) frequency among the positive hares found dead with severe histopathological lesions than among those found sick or apparently healthy. In contrast, the latter group was characterized by a higher frequency of the allele Leeu-DQA*14 as well as the proportion of heterozygous individuals (P = 0.000006 and P = 0.027). These data reveal a polarisation between EBHSV pathogenesis and MHC class II genotype within the European brown hare in Denmark.


Assuntos
Doenças dos Animais/genética , Infecções por Bunyaviridae/veterinária , Genes MHC da Classe II , Genótipo , Lagovirus/classificação , Alelos , Sequência de Aminoácidos , Doenças dos Animais/epidemiologia , Doenças dos Animais/virologia , Animais , Dinamarca , Éxons , Genes Virais , Predisposição Genética para Doença , Variação Genética , Geografia , Lebres/genética , Lebres/virologia , Lagovirus/genética , Lagovirus/isolamento & purificação , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência
15.
Arch Virol ; 158(10): 2193-6, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23640583

RESUMO

European brown hare syndrome (EBHS) is characterised by high mortality of European brown hares (Lepus europaeus) and mountain hares (Lepus timidus). European brown hare syndrome virus (EBHSV) and the closely related rabbit haemorrhagic disease virus (RHDV) comprise the genus Lagovirus, family Caliciviridae. In contrast to RHDV, which is well studied, with more than 30 complete genome sequences available, the only complete genome sequence available for EBHSV was obtained from a strain isolated in 1989 in France. EBHS was originally diagnosed in Sweden in 1980. Here, we report the complete coding sequences of two EBHSV strains isolated from European brown hares that died with liver lesions characteristic of EBHS in Sweden in 1982. These sequences represent the oldest complete coding sequences of EBHSV isolated from the original area of virus diagnosis. The genomic organisation is similar to that of the published French sequence. Comparison with this sequence revealed several nucleotide substitutions, corresponding to 6 % divergence. At the amino acid level, the Swedish strains are 2 % different from the French strain. Most amino acid substitutions were located within the major capsid protein VP60, but when considering the amino acid sequence length of each protein, VP10 is the protein with the highest percentage of amino acid differences. The same result was obtained when Swedish strains were compared. This evolutionary pattern has not been described previously for members of the genus Lagovirus.


Assuntos
Infecções por Bunyaviridae/veterinária , Lebres , Lagovirus/classificação , Lagovirus/genética , Animais , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/virologia , Genoma Viral , Dados de Sequência Molecular , RNA Viral/genética , Suécia/epidemiologia
16.
J Virol Methods ; 188(1-2): 148-52, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23261802

RESUMO

Recently, a new lagovirus enzootic in Australian wild rabbits was identified and described as rabbit calicivirus Australia-1 (RCV-A1). Unlike the closely related Rabbit Haemorrhagic Disease Virus (RHDV), which causes fulminant hepatitis and rabbit death, RCV-A1 does not appear to induce any clinical disease. RCV-A1 has been postulated to act as an imperfect natural vaccine to RHDV thus reducing RHDV-induced rabbit mortality, which is detrimental for bio-control of rabbits in Australia. This study was carried out to determine in which cells RCV-A1 replication occurs. An in situ hybridisation (ISH) protocol was developed using a RCV-A1 specific probe to localise the virus in rabbit tissues. The results were compared to those obtained with a quantitative RT-PCR assay that had previously been developed to measure RCV-A1 RNA in rabbit tissues. The histology of the tissues was also examined. ISH showed that virus replication, inferred by the presence of detectable RNA, was limited to a small number of epithelial cells towards the tip of the villi in the duodenum. Quantitative RT-PCR detected RCV-A1 RNA in jejunum, ileum and lymphoid tissue at day 3, 4 and 7 post-infection, but no hybridisation was detected in these tissues.


Assuntos
Infecções por Bunyaviridae/veterinária , Hibridização In Situ , Lagovirus/isolamento & purificação , Animais , Infecções por Bunyaviridae/virologia , Histocitoquímica , Íleo/virologia , Jejuno/virologia , Lagovirus/genética , Tecido Linfoide/virologia , Coelhos , Reação em Cadeia da Polimerase em Tempo Real
17.
Vet Microbiol ; 157(3-4): 345-54, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-22333288

RESUMO

Serological cross reactivity between the virulent rabbit haemorrhagic disease virus (RHDV) and the closely related but non-pathogenic rabbit calicivirus (RCV) makes it difficult to study the epidemiology of each virus and the interaction between them when both viruses co-circulate in wild rabbit populations. ELISA methods for the diagnosis of RHDV infection are well characterized, but no specific serological tests for RCV have been developed. Following the characterization of Australian non-pathogenic RCV-A1 strains, we used virus-like-particles (VLPs) and anti-RCV-A1 specific antibodies to establish a set of isotype ELISAs for detection of IgG, IgA and IgM in rabbit sera and secretory mucosal IgA in rectal swabs, and two competition ELISAs. These assays were used to discriminate between anti-RCV-A1 and anti-RHDV antibodies in rabbits. The isotype ELISAs were highly sensitive for detection of anti-RCV-A1 antibodies, but varying levels of cross reactivity from anti-RHDV antibodies occurred in the isotype ELISAs and one competition ELISA. However, the second competition ELISA specifically detected antibodies to RCV-A1 and showed no cross reactivity to anti-RHDV sera. These ELISAs provide important tools to monitor RCV-A1 infection when it occurs alone, and to discriminate between RHDV and RCV-A1 infection when they occur in the same rabbit population. When used in parallel with RHDV serology, they could be used to monitor the dynamics of these two closely related but pathogenically distinct viruses in wild and domestic rabbit populations.


Assuntos
Infecções por Bunyaviridae/veterinária , Infecções por Bunyaviridae/virologia , Infecções por Caliciviridae/veterinária , Infecções por Caliciviridae/virologia , Ensaio de Imunoadsorção Enzimática/métodos , Vírus da Doença Hemorrágica de Coelhos/isolamento & purificação , Lagovirus/isolamento & purificação , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Especificidade de Anticorpos , Austrália/epidemiologia , Infecções por Bunyaviridae/diagnóstico , Infecções por Bunyaviridae/epidemiologia , Infecções por Caliciviridae/diagnóstico , Infecções por Caliciviridae/epidemiologia , Reações Cruzadas , Vírus da Doença Hemorrágica de Coelhos/imunologia , Lagovirus/imunologia , Coelhos
18.
Vet Microbiol ; 154(1-2): 37-48, 2011 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-21831541

RESUMO

Here we describe an outbreak of European brown hare syndrome (EBHS) in a captive hare population. The EBHS outbreak occurred in March 2009, at the beginning of the breeding season. Overall mortality was 53% out of an original population of 61 animals. Animals between five and eleven months showed a significantly higher mortality rate than other age classes. Pregnant females either aborted their foetuses and survived or died pregnant. All foetuses (n=10) of the pregnant hares were PCR positive for EBHSV. Only one offspring born during the outbreak survived. Shortly after the outbreak, the surviving hares developed a specific anti-EBHSV titre between 1:80 and 1:2560, which dropped to 1:10-1:160 nine months later. Hares between one and three years of age developed a significantly higher titre than hares younger than one year or older than four years. Offspring born after the outbreak showed a lower titre of 1:10, indicating passive antibody transfer via placenta and milk. After two months, the titre was not detectable any longer. In December 2009, the captive population was vaccinated against EBHS virus with inactivated virus prepared from the organs of infected hares. The titres after the first vaccination ranged from 1:10 to 1:640, and after the second vaccination from 1:10 to 1:320. To estimate the effect of EBHS on reproduction, we compared the breeding seasons 2008 and 2009. Several possible sources of infection of the colony are discussed, but the definite cause could not be determined.


Assuntos
Infecções por Bunyaviridae/veterinária , Surtos de Doenças/veterinária , Lebres/virologia , Lagovirus/patogenicidade , Complicações Infecciosas na Gravidez/veterinária , Vacinas Virais/administração & dosagem , Animais , Anticorpos Antivirais/sangue , Infecções por Bunyaviridae/epidemiologia , Infecções por Bunyaviridae/imunologia , Feminino , Lebres/imunologia , Imunidade Materno-Adquirida , Masculino , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Vacinação , Vacinas Virais/imunologia
19.
Virology ; 410(2): 395-402, 2011 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-21195443

RESUMO

The existence of non-pathogenic RHDV strains was established when a non-lethal virus named rabbit calicivirus (RCV) was characterised in 1996 in Italy. Since then, different RNA sequences related to RHDV have been detected in apparently healthy domestic and wild rabbits, and recently a new lagovirus was identified in Australia. We have characterised from seropositive healthy domestic rabbits a non-lethal lagovirus that differs from RHDV in terms of pathogenicity, tissue tropism and capsid protein sequence. Phylogenetic analyses have revealed that it is close to the Ashington strain and to the RCV, but distinct. We proved experimentally that it is infectious but non-pathogenic and demonstrated that, contrary to the other described non-pathogenic lagoviruses, it induces antibodies that do not protect against RHDV. Our results indicate the existence of a gradient of cross-protection between circulating strains, from non-protective, partially protective to protective strains, and highlight the extent of diversity within the genus Lagovirus.


Assuntos
Infecções por Bunyaviridae/veterinária , Portador Sadio/veterinária , Lagovirus/classificação , Lagovirus/isolamento & purificação , Animais , Anticorpos Antivirais/sangue , Infecções por Bunyaviridae/imunologia , Infecções por Bunyaviridae/virologia , Portador Sadio/virologia , Análise por Conglomerados , Proteção Cruzada , Vírus da Doença Hemorrágica de Coelhos/genética , Lagovirus/genética , Lagovirus/patogenicidade , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Coelhos , Análise de Sequência de DNA , Homologia de Sequência
20.
Vet J ; 189(1): 89-94, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20643566

RESUMO

Cross-sectional studies were carried out on wild rabbit (Oryctolagus cuniculus) populations in Southern Spain to assess the prevalence of lagovirus infection and to identify potentially associated risk factors. A total of 619 blood and 487 liver samples from wild rabbits were collected from seven hunting areas with different Mediterranean ecosystems. Logistic regression analysis was used to assess associations between seropositivity and an extensive set of variables. The seroprevalence was 29.2% (95% CI: 25.6-32.8) and lagoviruses were not detected in liver samples. Logistic regression indicated that seropositivity to lagoviruses was associated with seropositivity to myxomatosis, wild rabbit density, the existence of artificial feeding sites, mean maximum monthly temperatures of 20-30 °C, and annual accumulated rainfall of >600 mm.


Assuntos
Animais Selvagens/virologia , Infecções por Bunyaviridae/veterinária , Lagovirus/isolamento & purificação , Coelhos/virologia , Animais , Infecções por Bunyaviridae/epidemiologia , Estudos Transversais , Feminino , Masculino , Mixomatose Infecciosa/epidemiologia , Apoio Nutricional/veterinária , Densidade Demográfica , Chuva , Fatores de Risco , Estudos Soroepidemiológicos , Espanha/epidemiologia , Temperatura
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