RESUMEN
The Equid alphaherpesvirus type 1 (EHV-1) infection can have devastating economic consequences in the horse industry due to large-scale outbreaks of abortions, perinatal foal mortality, and myeloencephalopathy. The present study analyzed the genome of two isolates obtained from aborted fetuses in Argentina, E/745/99 and E/1297/07. The E745/99 genome shares 98.2% sequence identity with Ab4, a reference EHV-1 strain. The E/1297/07 genome shares 99.8% identity with NY03, a recombinant strain containing part of ORF64 and part of the intergenic region from Equid alphaherpesvirus-4 (EHV-4). The E/1297/07 genome has the same breakpoints as other United States and Japanese recombinants, including NY03. The recombinant regions have varying numbers of tandem repeat sequences and different minor parental sequences (EHV-4), suggesting distinct origins of the recombinant events. These are the first complete genomes of EHV-1 from Argentina and South America available in the Databases.
Asunto(s)
Genoma Viral , Infecciones por Herpesviridae , Herpesvirus Équido 1 , Filogenia , Argentina , Herpesvirus Équido 1/genética , Herpesvirus Équido 1/aislamiento & purificación , Herpesvirus Équido 1/clasificación , Animales , Genoma Viral/genética , Infecciones por Herpesviridae/veterinaria , Infecciones por Herpesviridae/virología , Caballos/virología , Recombinación Genética , Enfermedades de los Caballos/virología , Sistemas de Lectura Abierta/genética , Secuenciación Completa del Genoma , ADN Viral/genéticaRESUMEN
BACKGROUND: Equine herpesvirus type 1 (EHV-1) is commonly associated with horse abortion. Currently, there are no reported cases of abortion resulting from EHV-1 infection in donkeys. RESULTS: This was the first survey-based study of Chinese donkeys. The presence of EHV-1 was identified by PCR. This survey was conducted in Chabuchar County, North Xinjiang, China, in 2020. A donkey EHV-1 strain (Chabuchar/2020) was successfully isolated in MDBK cells. Seventy-two of 100 donkey sera were able to neutralize the isolated EHV-1. Moreover, the ORF33 sequence of the donkey-origin EHV-1 Chabuchar/2020 strain showed high levels of similarity in both its nucleotide (99.7â100%) and amino acid (99.5â100%) sequences, with those of horse EHV-1 strains. EHV-1 Chabuchar/2020 showed significant consistency and was classified within cluster 1 of horse EHV-1 strains. Further, analysis of the expected ORF30 nucleotide sequence revealed that donkey EHV-1 strains contained guanine at position 2254, resulting in a change to aspartic acid at position 752 of the viral DNA polymerase. Therefore, these strains were classified as horse neuropathogenic strains. Lastly, a phylogenetic tree was constructed using the partial ORF68 nucleotide sequences, showing that the identified donkey EHV-1 strain and the EHV-1 strain found in aborted Yili horses in China comprised a novel independent VIII group. CONCLUSION: This study showed the first isolation and identification of EHV-1 as an etiological agent of abortions in donkeys. Further analysis of the ORF33, ORF30, and ORF68 sequences indicated that the donkey EHV-1 contained the neuropathogenic genotype of strains in the VIII group. It is thus important to be aware of EHV-1 infection in the donkey population, even though the virus has only been identified in donkey abortions in China.
Asunto(s)
Equidae , Infecciones por Herpesviridae , Herpesvirus Équido 1 , Pulmón , Filogenia , Animales , Equidae/virología , Herpesvirus Équido 1/aislamiento & purificación , Herpesvirus Équido 1/genética , Herpesvirus Équido 1/clasificación , China , Infecciones por Herpesviridae/veterinaria , Infecciones por Herpesviridae/virología , Pulmón/virología , Feto Abortado/virología , Femenino , ADN Viral/genética , Sistemas de Lectura Abierta , Análisis de Secuencia de ADN , Embarazo , Reacción en Cadena de la PolimerasaRESUMEN
Equid Gamma herpesvirus (eGHV) infections have been reported worldwide and may be correlated with clinical signs, e.g., affecting the respiratory tract in young horses. eGHV are shed by healthy horses as well as horses with respiratory tract disease. The prevalence in healthy Swiss horses is unknown to date but this data would provide valuable information for causal diagnosis in clinical cases and formulation of biosecurity recommendations. Nasal swabs from 68 healthy horses from 12 Swiss stables and 2 stables near the Swiss border region in Germany were analyzed by panherpes nested PCR. Positive samples were sequenced. A multivariable model was used to determine if sex, age, breed, canton, or stable had a significant effect on the shedding status of each detected eGHV. Overall, the eGHV prevalence was 59% (n = 68); the prevalence for equid herpesvirus-2 (EHV-2), equid herpesvirus-5 (EHV-5) and asinine herpesvirus-5 (AHV-5) was 38%, 12% and 9%, respectively. Co-infections with multiple eGHVs were observed in 25% of the positive samples. The odds of shedding EHV-2 decreased with age (p = 0.01) whereas the odds of shedding AHV-5 increased with age (p = 0.04). Breed, sex, canton, or stable had no significant association with eGHV shedding. As EHV-2 shedding was common in healthy horses a positive PCR result must be interpreted with caution regarding the formulation of biosecurity recommendations and causal diagnosis. As EHV-5 and AHV-5 shedding was less common than EHV-2, a positive test result is more likely to be of clinical relevance. Shedding of multiple eGHV complicates the interpretation of positive test results in a horse.
Asunto(s)
Herpesvirus Équido 1/aislamiento & purificación , Nariz/virología , Enfermedades Respiratorias/veterinaria , Esparcimiento de Virus , Animales , Anticuerpos Antivirales/sangre , ADN Viral/genética , Femenino , Gammaherpesvirinae/aislamiento & purificación , Gammaherpesvirinae/fisiología , Alemania/epidemiología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/genética , Herpesvirus Équido 1/fisiología , Enfermedades de los Caballos/epidemiología , Enfermedades de los Caballos/virología , Caballos , Masculino , Enfermedades Respiratorias/epidemiología , Enfermedades Respiratorias/virología , Suiza/epidemiología , ViremiaRESUMEN
The objective of this study was to determine if the genotype of equine herpesvirus-1 (EHV-1) impacted clinical disease and outcome of horses with laboratory confirmed equine herpesvirus myeloencephalopathy (EHM). Medical records from 65 horses diagnosed with EHM from 2011 to 2019 were reviewed for signalment, presence and severity of clinical signs (lethargy, fever, ataxia, urinary incontinence) and outcome. Horses were further grouped based on the EHV-1 genotype into neuropathic (D752) or non-neuropathic (N752) EHV-1 infection. Between the two EHV-1 genotype groups, age and sex distributions were similar, although breed distribution was different (Quarter Horses and Saddlebreds were overrepresented and Warmbloods were underrepresented in the EHV-1 D752 group compared to the EHV-1 N752 group; P = 0.009). Lethargy, fever, ataxia and outcome were not significantly different between the two EHV-1 genotype groups (P > 0.05). However, urinary incontinence was significantly more frequently reported in horses infected with the D752 genotype of EHV-1 (P=0.04). Contrary to previous studies, the present study showed no difference in frequency of genotype (D752 or N752) among 65 horses with EHM and, with the exception of urinary incontinence, no difference in clinical disease or outcome related to the EHV-1 genotype.
Asunto(s)
Genotipo , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/virología , Animales , Ataxia/veterinaria , Femenino , Fiebre/veterinaria , Infecciones por Herpesviridae/epidemiología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/patogenicidad , Caballos , Letargia/veterinaria , Masculino , Estudios Retrospectivos , Incontinencia Urinaria/veterinariaRESUMEN
Equine herpesvirus 1 (EHV-1) is an Alphaherpesvirus infecting not only horses but also other equid and non-equid mammals. It can cause respiratory distress, stillbirth and neonatal death, abortion, and neurological disease. The different forms of disease induced by EHV-1 infection can have dramatic consequences on the equine industry, and thus the virus represents a great challenge for the equine and scientific community. This report describes the progress of a major EHV-1 outbreak that took place in Normandy in 2009, during which the three forms of disease were observed. A collection of EHV-1 strains isolated in France and Belgium from 2012 to 2018 were subsequently genetically analysed in order to characterise EHV-1 strain circulation. The open reading frame 30 (ORF30) non-neuropathogenic associated mutation A2254 was the most represented among 148 samples analysed in this study. ORF30 was also sequenced for 14 strains and compared to previously published sequences. Finally, a more global phylogenetic approach was performed based on a recently described Multilocus Sequence Typing (MLST) method. French and Belgian strains were clustered with known strains isolated in United Kingdom and Ireland, with no correlation between the phylogeny and the time of collection or location. This new MLST approach could be a tool to help understand epidemics in stud farms.
Asunto(s)
Aborto Veterinario/epidemiología , Brotes de Enfermedades , Infecciones por Herpesviridae/epidemiología , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/epidemiología , Enfermedades del Sistema Nervioso/epidemiología , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/veterinaria , Aborto Veterinario/virología , Animales , Bélgica/epidemiología , ADN Viral/genética , Femenino , Francia/epidemiología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/aislamiento & purificación , Enfermedades de los Caballos/virología , Caballos , Masculino , Tipificación de Secuencias Multilocus , Sistemas de Lectura Abierta , Filogenia , Reino UnidoRESUMEN
Equid alphaherpesvirus 1 (EHV-1) is an important pathogen of horses. It is spread worldwide and causes significant economic losses. The ORF33 gene has a conserved region that is often used as target in diagnostic PCR protocols. Single nucleotide point (SNP) mutations in ORF30 are usually used to distinguish between neuropathogenic and non-neuropathogenic genotypes. An ORF68 SNP-based scheme has been used for grouping different isolates. Recently, the highest number of variable sites in EHV-1 from the UK has been found in ORF34. In this study, EHV-1 positive samples from Italian horses with a history of abortion were investigated by amplifying and sequencing the ORF30, ORF33, ORF34 and ORF68 genes. Most animals were infected by the neuropathogenic type A2254G. A 118 bp deletion was found at nucleotide positions 701-818 of the ORF68 gene, making impossible to assign the samples to a known group. Sequencing of the ORF34 gene with a newly designed nested PCR showed new SNPs. Analysis of these sequences and of those obtained from genetic databases allowed the identification of at least 12 groups. These data add depth to the knowledge of EHV-1 genotypes circulating in Italy.
Asunto(s)
Variación Genética , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/virología , Sistemas de Lectura Abierta , Animales , ADN Viral/genética , Bases de Datos de Ácidos Nucleicos , Genotipo , Herpesvirus Équido 1/clasificación , Caballos/virología , Italia , Polimorfismo de Nucleótido Simple , Análisis de Secuencia de ADNRESUMEN
Equid alphaherpesvirus 1 (EHV-1) infections can have a major impact on the horse industry and equine welfare by causing abortion or respiratory or neurologic disease. A single nucleotide polymorphism (A2254âG2254) in open reading frame (ORF) 30, encoding the catalytic subunit of the DNA polymerase, has been shown to be a strong predictive marker for neuropathogenicity. Given that a previously established real-time PCR (rtPCR) protocol yielded unsatisfactory results concerning determination of the EHV-1 genotype, we developed and evaluated a new conventional PCR protocol enabling identification of the genotype by sequencing and restriction enzyme analysis (REA). Thirty samples from horses with signs typical for EHV-1 infection were tested by rtPCR and our new conventional PCR. The results showed that compared to rtPCR, the conventional PCR protocol combined with sequencing and REA was more reliable concerning unambiguous determination of the EHV-1 genotype. Results of our new assay confirmed previous findings, according to which the non-neuropathogenic genotype A2254 is predominantly found in animals with fever, respiratory signs, and abortions or perinatal mortality, whereas the neuropathogenic genotype G2254 is primarily detected in animals suffering from neurologic disease. In some samples, results pointed towards coinfection with both genotypes. Further studies are required in order to elucidate the significance of infections with genotype A2254 and G2254 in neurologic and non-neurologic cases, respectively.
Asunto(s)
Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/clasificación , Enfermedades de los Caballos/virología , Enfermedades del Sistema Nervioso/veterinaria , Polimorfismo de Nucleótido Simple , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Animales , ADN Polimerasa Dirigida por ADN/genética , Femenino , Genotipo , Infecciones por Herpesviridae/virología , Herpesvirus Équido 1/genética , Caballos , Enfermedades del Sistema Nervioso/virología , Sistemas de Lectura Abierta , Embarazo , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Mapeo Restrictivo/veterinariaRESUMEN
Equid alpha-herpesviruses (EHV) are responsible for different diseases in equine population. EHV-1 causes respiratory diseases, abortions and nervous disorders, EHV-4 causes respiratory diseases and sporadic abortion, while EHV-3 is responsible of equine coital exanthema. In view of the lack of efficacy of vaccines against EHV-1 and EHV-4 and in the absence of vaccines against EHV-3, the use of antiviral treatment is of great interest. In this study, we documented the interest of the Real-Time Cell Analysis (RTCA) technology to monitor the cytopathic effects induced by these viruses on equine dermal cells, and established the efficacy of this method to evaluate the antiviral effect of aciclovir (ACV) and ganciclovir (GCV). In addition, the RTCA technology has also been found appropriate for the high-throughput screening of small molecules against EHV, allowing the identification of spironolactone as a novel antiviral against EHV.
Asunto(s)
Antivirales/farmacología , Impedancia Eléctrica , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/efectos de los fármacos , Ensayos Analíticos de Alto Rendimiento/métodos , Animales , Línea Celular , Efecto Citopatogénico Viral/efectos de los fármacos , Infecciones por Herpesviridae/patología , Infecciones por Herpesviridae/virología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 3/efectos de los fármacos , Herpesvirus Équido 4/efectos de los fármacos , Caballos , Espironolactona/farmacologíaRESUMEN
BACKGROUND: Equid alphaherpesvirus 1 (EHV-1) is one of the main infectious causative agents of abortion in mares and can also be associated with stillbirth, neonatal foal death, rhinopneumonitis in young horses and a neurological disorder called equine herpesvirus myeloencephalopathy (EHM). The neuropathogenicity of the virus was shown to be significantly higher in EHV-1 strains that carry a single nucleotide point (SNP) mutation in the ORF30, which encodes a catalytic subunit of viral DNA polymerase (ORF30 D752). Another gene, ORF68 is frequently used for phylogenetic analysis of EHV-1. METHODS: 27 EHV-1 strains isolated from aborted equine fetuses in Poland, collected between 1993 and 2017, were subjected to PCR targeting the open reading frames (ORFs) 30 and 68 of the EHV-1 genome. PCR products obtained were sequenced and SNPs were analyzed and compared to sequences available in GenBank. RESULTS: None of the analyzed sequences belonged to the ORF30 D752neuropathogenic genotype: all EHV-1 belonged to the non-neuropathogenic variant N752. On the basis of ORF68 sequences, the majority of EHV-1 sequences (76.9%) cannot be assigned to any of the known groups; only six sequences (23.1%) clustered within groups II and IV. CONCLUSIONS: EHV-1 strains obtained from abortion cases belong to the non-neuropathogenic genotype. Many EHV-1 ORF68 sequences have similar SNPs to those already described in Poland, but a clear geographical distribution was not observed. A single particular ORF68 sequence type was observed in strains isolated from 2001 onwards.
Asunto(s)
ADN Polimerasa Dirigida por ADN/genética , Encefalomielitis/veterinaria , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/virología , Feto Abortado/virología , Animales , ADN Viral/genética , Brotes de Enfermedades/veterinaria , Encefalomielitis/virología , Femenino , Variación Genética/genética , Infecciones por Herpesviridae/virología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/aislamiento & purificación , Caballos , Sistemas de Lectura Abierta/genética , Polonia , Polimorfismo de Nucleótido Simple/genéticaRESUMEN
Equine herpesvirus 1 (EHV1) is considered as a major pathogen of Equidae, causing symptoms from mild respiratory disease to late-term abortion and neurological disorders. Different EHV1 strains circulating in the field have been characterized to be of abortigenic or neurovirulent phenotype. Both variants replicate in a plaque-wise manner in the epithelium of the upper respiratory tract (URT), where the abortigenic strains induce more prominent viral plaques, compared to the neurovirulent strains. Considering the differences in replication at the URT, we hypothesized that abortigenic strains may show an increased ability to modulate the type I IFN secretion/signaling pathway, compared to strains that display the neurovirulent phenotype. Here, we analyze IFN levels induced by abortigenic and neurovirulent EHV1 using primary respiratory epithelial cells (EREC) and respiratory mucosa ex vivo explants. Similar levels of IFNα (~70 U/ml) were detected in explants inoculated with both types of EHV1 strains from 48 to 72 hpi. Second, EREC and mucosa explants were treated with recombinant equine IFNα (rEqIFNα) or Ruxolitinib (Rux), an IFN signaling inhibitor, prior to and during inoculation with abortigenic or neurovirulent EHV1. Replication of both EHV1 variants was suppressed by rEqIFNα. Further, addition of Rux increased replication in a concentration-dependent manner, indicating an IFN-susceptibility for both variants. However, in two out of three horses, at a physiological concentration of 100 U/ml of rEqIFNα, an increase in abortigenic EHV1 replication was observed compared to 10 U/ml of rEqIFNα, which was not observed for the neurovirulent strains. Moreover, in the presence of Rux, the plaque size of the abortigenic variants remained unaltered, whereas the typically smaller viral plaques induced by the neurovirulent variants became larger. Overall, our results demonstrate the importance of IFNα in the control of EHV1 replication in the URT for both abortigenic and neurovirulent variants. In addition, our findings support the speculation that abortigenic variants of EHV1 may have developed anti-IFN mechanisms that appear to be absent or less pronounced in neurovirulent EHV1 strains.
Asunto(s)
Herpesvirus Équido 1/crecimiento & desarrollo , Herpesvirus Équido 1/inmunología , Interacciones Huésped-Patógeno , Evasión Inmune , Factores Inmunológicos/análisis , Interferón-alfa/análisis , Animales , Células Cultivadas , Células Epiteliales/inmunología , Células Epiteliales/virología , Herpesvirus Équido 1/clasificación , Caballos , Modelos Biológicos , Técnicas de Cultivo de Órganos , Mucosa Respiratoria/inmunología , Mucosa Respiratoria/virología , Ensayo de Placa Viral , Replicación ViralRESUMEN
Equine herpesvirus-1 (EHV-1) infection is an important and highly prevalent disease in equine populations worldwide. Previously we have demonstrated that a neuropathogenic strain of EHV-1, T953, suppresses the host cell's antiviral type-I interferon (IFN) response in vitro. Whether or not this is unique to EHV-1 strains possessing the neuropathogenic genotype has been undetermined. Here, we examined whether there is any direct relationship between neuropathogenic genotype and the induced IFN-ß response in equine endothelial cells (EECs) infected with 10 different strains of EHV-1. The extent of virus cell-to-cell spread following infection in EECs was also compared between the neuropathogenic and the non-neuropathogenic genotype of EHV-1. We then compared IFN-ß and the total type-I IFN protein suppression between T953, an EHV-1 strain that is neuropathogenic and T445, an EHV-4 strain mainly associated only with respiratory disease. Data from our study revealed no relationship between the neuropathogenic genotype of EHV-1 and the induced IFN-ß mRNA by the host cell. Results also indicate no statistically significant difference in plaque sizes of both genotypes of EHV-1 produced in EECs. However, while the T953 strain of EHV-1 was able to suppress IFN-ß mRNA and type-I IFN biological activity at 12â¯h post-infection (hpi), EHV-4 weakly induces both IFN-ß mRNA and type-I IFN biological activity. This finding correlated with a statistically significant difference in the mean plaque sizes produced by the two EHV subtypes in EECs. Our data help illuminate how EHV-1, irrespective of its genotype, evades the host cell's innate immune response thereby enabling viral spread to susceptible cells.
Asunto(s)
Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/patogenicidad , Enfermedades de los Caballos/inmunología , Interferón beta/inmunología , Animales , Células Endoteliales/inmunología , Células Endoteliales/virología , Genotipo , Infecciones por Herpesviridae/inmunología , Herpesvirus Équido 1/clasificación , Enfermedades de los Caballos/virología , Caballos/inmunología , Evasión Inmune , Inmunidad Innata , Interferón Tipo I/inmunologíaRESUMEN
BACKGROUND: The varicelloviruses comprise a genus within the alphaherpesvirus subfamily, and infect both humans and other mammals. Recently, next-generation sequencing has been used to generate genomic sequences of several members of the Varicellovirus genus. Here, currently available varicellovirus genomic sequences were used for phylogenetic, recombination, and genetic distance analysis. RESULTS: A phylogenetic network including genomic sequences of individual species, was generated and suggested a potential restriction between the ungulate and non-ungulate viruses. Intraspecies genetic distances were higher in the ungulate viruses (pseudorabies virus (SuHV-1) 1.65%, bovine herpes virus type 1 (BHV-1) 0.81%, equine herpes virus type 1 (EHV-1) 0.79%, equine herpes virus type 4 (EHV-4) 0.16%) than non-ungulate viruses (feline herpes virus type 1 (FHV-1) 0.0089%, canine herpes virus type 1 (CHV-1) 0.005%, varicella-zoster virus (VZV) 0.136%). The G + C content of the ungulate viruses was also higher (SuHV-1 73.6%, BHV-1 72.6%, EHV-1 56.6%, EHV-4 50.5%) compared to the non-ungulate viruses (FHV-1 45.8%, CHV-1 31.6%, VZV 45.8%), which suggests a possible link between G + C content and intraspecies genetic diversity. Varicellovirus clade nomenclature is variable across different species, and we propose a standardization based on genomic genetic distance. A recent study reported no recombination between sequenced FHV-1 strains, however in the present study, both splitstree, bootscan, and PHI analysis indicated recombination. We also found that the recently sequenced Brazilian CHV-1 strain BTU-1 may contain a genetic signal in the UL50 gene from an unknown varicellovirus. CONCLUSION: Together, the data contribute to a greater understanding of varicellovirus genomics, and we also suggest a new clade nomenclature scheme based on genetic distances.
Asunto(s)
Varicellovirus/clasificación , Varicellovirus/genética , Composición de Base , Codón , Herpesvirus Bovino 1/clasificación , Herpesvirus Bovino 1/genética , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/genética , Herpesvirus Équido 4/clasificación , Herpesvirus Équido 4/genética , Mutación , Filogenia , Recombinación GenéticaRESUMEN
We describe the histopathologic, immunohistochemical, and molecular features of a case of meningoencephalitis in a Thomson's gazelle ( Eudorcas thomsonii) naturally infected with zebra-borne equid herpesvirus 1 (EHV-1) and the implications for the molecular detection of zebra-borne EHV-1. A 4-y-old female Thomson's gazelle was submitted for postmortem examination; no gross abnormalities were noted except for meningeal congestion. Microscopic evaluation demonstrated multifocal nonsuppurative meningoencephalitis with intranuclear eosinophilic and amphophilic inclusion bodies and EHV-9 antigen in neurons. PCR demonstrated the presence of a herpesvirus with a nucleotide sequence 99-100% identical to the corresponding sequences of zebra-borne EHV-1 and of EHV-9 strains. To determine whether EHV-1 or EHV-9 was involved, a PCR with a specific primer set for EHV-9 ORF59/60 was used. The sequence was identical to that of 3 recognized zebra-borne EHV-1 strains and 91% similar to that of EHV-9. This isolate was designated as strain LM2014. The partial glycoprotein G ( gG) gene sequence of LM2014 was also identical to the sequence of 2 zebra-borne EHV-1 strains (T-529 isolated from an onager, 94-137 from a Thomson's gazelle). The histologic lesions of encephalitis and antigen localization in this gazelle indicate prominent viral neurotropism, and lesions were very similar to those seen in EHV-1- and EHV-9-infected non-equid species. Histologic lesions caused by EHV-9 and zebra-borne EHV-1 are therefore indistinguishable.
Asunto(s)
Antílopes , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/fisiología , Meningoencefalitis/veterinaria , Animales , Animales de Zoológico , Equidae/virología , Femenino , Infecciones por Herpesviridae/patología , Infecciones por Herpesviridae/virología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/genética , Louisiana , Meningoencefalitis/patología , Meningoencefalitis/virología , Filogenia , Análisis de Secuencia de ADN/veterinariaRESUMEN
Equine herpesvirus 1 (EHV1) is a common pathogen of horses that causes upper respiratory tract disease, abortion, neonatal death and neurological disease. The neurological form of disease is called equine herpesvirus myeloencephalopathy (EHM). During the past decade, the incidence of EHM has been on the rise in Europe, North America, Australia and Asia. Some EHV1 isolates causing EHM exhibit a single-nucleotide polymorphism (SNP) in the DNA polymerase gene (ORF30) at position 2254 (A2254 to G2254). Further, based on polymorphism in the ORF68, EHV1 isolates have been classified into different groups. The aim of the present study was to estimate the genetic diversity of EHV1 and to determine the prevalence of the neuropathogenic genotype of EHV1 in India. Out of 133 clinical specimens from abortion cases in northern India, 56 were positive for EHV1 infection. Analysis of the A/G SNP by real-time PCR and sequence analysis revealed that 54 of 56 samples (96.43 %) were of the non-neuropathogenic genotype (A2254), while two (3.57 %) had the neuropathogenic marker (G2254). Sequence analysis of the polymorphic region of ORF68 of EHV1 isolates (n = 9) from India indicated that the Delhi/1998, Tohana-2/2013, Hisar-2/2014 and Hisar-15/1990 isolates belonged to group 4, while the Jind/1996, Rajasthan/1998, Delhi-3/2007 and Tohana-5/1996 isolates clustered within group 5. One isolate (Hisar-7/1990) exhibited SNPs at positions C710 and C713, forming a separate group. Here, we report for the first time the detection of neuropathogenic genotypes of EHV1 in India and show that Indian EHV1 isolates cluster within groups 4 and 5.
Asunto(s)
Aborto Veterinario/epidemiología , Brotes de Enfermedades , Encefalomielitis/veterinaria , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/aislamiento & purificación , Enfermedades de los Caballos/epidemiología , Aborto Veterinario/virología , Animales , Análisis por Conglomerados , Encefalomielitis/complicaciones , Encefalomielitis/epidemiología , Variación Genética , Genotipo , Infecciones por Herpesviridae/complicaciones , Infecciones por Herpesviridae/epidemiología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/virología , Caballos , India/epidemiología , Reacción en Cadena de la Polimerasa , Polimorfismo de Nucleótido Simple , Prevalencia , Análisis de Secuencia de ADNRESUMEN
Recombination in alphaherpesviruses allows evolution to occur in viruses that have an otherwise stable DNA genome with a low rate of nucleotide substitution. High-throughput sequencing of complete viral genomes has recently allowed natural (field) recombination to be studied in a number of different alphaherpesviruses, however, such studies have not been applied to equine herpesvirus 1 (EHV-1) or equine herpesvirus 4 (EHV-4). These two equine alphaherpesviruses are genetically similar, but differ in their pathogenesis and epidemiology. Both cause economically significant disease in horse populations worldwide. This study used high-throughput sequencing to determine the full genome sequences of EHV-1 and EHV-4 isolates (11 and 14 isolates, respectively) from Australian or New Zealand horses. These sequences were then analysed and examined for evidence of recombination. Evidence of widespread recombination was detected in the genomes of the EHV-4 isolates. Only one potential recombination event was detected in the genomes of the EHV-1 isolates, even when the genomes from an additional 11 international EHV-1 isolates were analysed. The results from this study reveal another fundamental difference between the biology of EHV-1 and EHV-4. The results may also be used to help inform the future safe use of attenuated equine herpesvirus vaccines.
Asunto(s)
Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/genética , Herpesvirus Équido 4/genética , Enfermedades de los Caballos/virología , Recombinación Genética , Animales , Secuencia de Bases , Genoma Viral , Infecciones por Herpesviridae/virología , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/aislamiento & purificación , Herpesvirus Équido 4/clasificación , Herpesvirus Équido 4/aislamiento & purificación , Caballos , Datos de Secuencia Molecular , Nueva Zelanda , FilogeniaRESUMEN
Partial nucleotide sequences of ORF72 (glycoprotein D, gD), ORF64 (infected cell protein 4, ICP4) and ORF30 (DNA polymerase) genes were compared with corresponding sequences of EHV-1 reference strains to characterize the molecular variability of Brazilian strains. Virus isolation assays were applied to 74 samples including visceral tissue, total blood, cerebrospinal fluid (CSF) and nasal swabs of specimens from a total of 64 animals. Only one CSF sample (Iso07/05 strain) was positive by virus isolation in cell culture. EHV-1 Iso07/05 neurologic strain and two abortion visceral tissues samples (Iso11/06 and Iso33/06) were PCR-positive for ORF33 (glycoprotein B, gB) gene of EHV-1. A sequence analysis of the ORF72, ORF64 and ORF30 genes from three EHV-1 archival strains (A3/97, A4/72, A9/92) and three clinical samples (Iso07/05, Iso11/06 and Iso33/06) suggested that among Brazilian EHV-1 strains, the amplified region of the gD gene sequence is highly conserved. Additionally, the analysis of ICP4 gene showed high nucleotide and amino acid identities when compared with genotype P strains, suggesting that the EHV-1 Brazilian strains belonged to the same group. All the EHV-1 Brazilian strains were classified as non-neuropathogenic variants (N752) based on the ORF30 analysis. These findings indicate a high conservation of the gD-, ICP4- and ORF30-encoding sequences. Different pathotypes of the EHV-1 strain might share identical genes with no specific markers, and tissue tropism is not completely dependent on the gD envelope, immediate-early ICP4 and DNA polymerase proteins.
Asunto(s)
Variación Genética , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/virología , Animales , Brasil , Análisis por Conglomerados , Secuencia Conservada , ADN Viral/química , ADN Viral/genética , Genotipo , Infecciones por Herpesviridae/virología , Caballos , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Filogenia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido NucleicoRESUMEN
Partial nucleotide sequences of ORF72 (glycoprotein D, gD), ORF64 (infected cell protein 4, ICP4) and ORF30 (DNA polymerase) genes were compared with corresponding sequences of EHV-1 reference strains to characterize the molecular variability of Brazilian strains. Virus isolation assays were applied to 74 samples including visceral tissue, total blood, cerebrospinal fluid (CSF) and nasal swabs of specimens from a total of 64 animals. Only one CSF sample (Iso07/05 strain) was positive by virus isolation in cell culture. EHV-1 Iso07/05 neurologic strain and two abortion visceral tissues samples (Iso11/06 and Iso33/06) were PCR-positive for ORF33 (glycoprotein B, gB) gene of EHV-1. A sequence analysis of the ORF72, ORF64 and ORF30 genes from three EHV-1 archival strains (A3/97, A4/72, A9/92) and three clinical samples (Iso07/05, Iso11/06 and Iso33/06) suggested that among Brazilian EHV-1 strains, the amplified region of the gD gene sequence is highly conserved. Additionally, the analysis of ICP4 gene showed high nucleotide and amino acid identities when compared with genotype P strains, suggesting that the EHV-1 Brazilian strains belonged to the same group. All the EHV-1 Brazilian strains were classified as non-neuropathogenic variants (N752) based on the ORF30 analysis. These findings indicate a high conservation of the gD-, ICP4- and ORF30-encoding sequences. Different pathotypes of the EHV-1 strain might share identical genes with no specific markers, and tissue tropism is not completely dependent on the gD envelope, immediate-early ICP4 and DNA polymerase proteins.
Asunto(s)
Animales , Variación Genética , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/clasificación , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/virología , Brasil , Análisis por Conglomerados , Secuencia Conservada , ADN Viral/química , ADN Viral/genética , Genotipo , Caballos , Infecciones por Herpesviridae/virología , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Filogenia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido NucleicoRESUMEN
A particularly severe equine herpesvirus type 1 (EHV-1) abortion outbreak occurred at a breeding farm in northern Germany. Sixteen of 25 pregnant mares that had received regular vaccination using an inactivated vaccine aborted and two gave birth to weak non-viable foals in a span of three months, with 89% of cases occurring within 40 days after the initial abortion case. Virological examinations revealed the presence of EHV-1 in all cases of abortion and serological follow-up in mares confirmed recent infection. Molecular studies identified a neuropathogenic variant (Pol/ORF30 A2254 to G2254) that belonged to geographical group 4 of EHV-1 isolates. The abortion outbreak was preceded by a case of mild ataxia of unknown cause in a mare that aborted four months after the ataxic episode. Although vaccination of pregnant mares did not prevent abortion, good EHV-1 immune status of the population at the time of outbreak may have had an impact in the failure of manifestation of the neurological form of the disease.
Asunto(s)
Aborto Veterinario/virología , Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/clasificación , Enfermedades de los Caballos/virología , Aborto Veterinario/epidemiología , Animales , Brotes de Enfermedades/veterinaria , Femenino , Alemania/epidemiología , Infecciones por Herpesviridae/epidemiología , Infecciones por Herpesviridae/virología , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/epidemiología , Caballos , EmbarazoRESUMEN
Equid herpesvirus (EHV) type 1 is a common pathogen of horses with worldwide distribution. Although severe tracheobronchitis has been described in some field outbreaks of EHV-1 respiratory disease, many EHV-1 infections occur asymptomatically or are accompanied only by signs of mild respiratory disease. However, EHV-1 infection can also result in outcomes other than respiratory disease such as abortion, neonatal death or neurological disease. This review provides an overview of the diagnosis, treatment and prognosis for EHV-1-associated diseases, with an emphasis on neurological presentations of EHV-1 infection.
Asunto(s)
Infecciones por Herpesviridae/veterinaria , Herpesvirus Équido 1/clasificación , Enfermedades de los Caballos/virología , Animales , Infecciones por Herpesviridae/diagnóstico , Infecciones por Herpesviridae/prevención & control , Infecciones por Herpesviridae/terapia , Herpesvirus Équido 1/genética , Enfermedades de los Caballos/diagnóstico , Enfermedades de los Caballos/prevención & control , Enfermedades de los Caballos/terapia , Caballos , Vacunas Virales/inmunologíaRESUMEN
Equid herpesvirus (EHV) type 1 is a common pathogen of horses with worldwide distribution. Infection with EHV-1 can be subclinical, or can result in sociologically and economically important outcomes such as abortion, neonatal death or neurological disease. The perceived recent increase in the reported cases of EHV-1 neurological disease in the United States of America and Europe over the past decade has caused concerns amongst veterinarians and horse owners worldwide. This review provides an update on the recent developments in our understanding of the pathogenesis and epidemiology of EHV-1 and associated diseases, with an emphasis on epidemiological data from Australasia. Many aspects of the pathogenesis and epidemiology of equine herpesvirus myeloencephalopathy still remain to be elucidated. This is an active area of current research worldwide.