Equine herpesvirus-1 genotype did not significantly affect clinical signs and disease outcome in 65 horses diagnosed with equine herpesvirus-1 myeloencephalopathy

Pusterla, Nicola; Hatch, Kelly; Crossley, Beate; Wademan, Cara; Barnum, Samantha; Flynn, K.

doi:10.1016/j.tvjl.2019.105407

Cited by 18 publications

(13 citation statements)

References 12 publications

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“…The possible delay in diagnosis and application of biosecurity measures could be identified as the possible trigger for virus spread. The epidemiological pattern observed during this epidemic was similar to other outbreaks reported in last decades in Europe (Goehring et al, 2006;Gryspeerdt et al, 2011;Pronost et al, 2012;Walter et al, 2013;van Galen et al, 2015; and worldwide (Henninger et al, 2007;Tsujimura et al, 2011;Burgess et al, 2012;McFadden et al, 2016;Negussie et al, 2017b;Pusterla et al, 2020) with movements of horses carrying the infection to other premises from the index one.…”

Section: Presence and Distributionsupporting

confidence: 86%

“…The ability to cause EHM was associated in the past with specific EHV-1 strains (the so-called neuropathogenic strains) with a specific DNA polymerase gene mutation (gene open reading frame 30: N752), but virus strains without this mutation have been isolated in several outbreaks with horses suffering for neurological signs (Goehring et al, 2006;Nugent et al, 2009;van Galen et al, 2015;Garvey et al, 2019;Dunuwille et al, 2020;Sutton et al, 2020;Pusterla et al, 2020;Vereecke et al, 2021).…”

Section: Morbiditymentioning

confidence: 99%

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Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): infection with Equine Herpesvirus‐1

Nielsen¹,

Álvarez²,

Bicout³

et al. 2022

EFS2

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Equine Herpesvirus‐1 infection has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of: Article 7 on disease profile and impacts, Article 5 on the eligibility of the disease to be listed, Article 9 for the categorisation of the disease according to disease prevention and control measures as in Annex IV and Article 8 on the list of animal species related to Equine Herpesvirus‐1 infection. The assessment has been performed following a methodology composed of information collection and compilation, and expert judgement on each criterion at individual and collective level. The outcome is the median of the probability ranges provided by the experts, which indicates whether the criterion is fulfilled (66–100%) or not (0–33%), or whether there is uncertainty about fulfilment (33–66%). For the questions where no consensus was reached, the different supporting views are reported. According to the assessment performed, Equine Herpesvirus‐1 infection can be considered eligible to be listed for Union intervention according to Article 5 of the Animal Health Law with 33–90% certainty. According to the criteria as in Annex IV of the AHL related to Article 9 of the AHL for the categorisation of diseases according to the level of prevention and control, it was assessed with less than 1% certainty that EHV‐1 fulfils the criteria as in Section 1 (category A), 1–5% for the criteria as in Section 2 (category B), 10–66% for the criteria as in Section 3 (category C), 66–90% for the criteria as in Section 4 (category D) and 33–90% for the criteria as in Section 5 (category E). The animal species to be listed for EHV‐1 infection according to Article 8(3) criteria are the species belonging to the families of Equidae, Bovidae, Camelidae, Caviidae, Cervidae, Cricetidae, Felidae, Giraffidae, Leporidae, Muridae, Rhinocerontidae, Tapiridae and Ursidae.

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Section: Presence and Distributionsupporting

confidence: 86%

Section: Morbiditymentioning

confidence: 99%

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): infection with Equine Herpesvirus‐1

Nielsen¹,

Álvarez²,

Bicout³

et al. 2022

EFS2

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“…According to the authors, the probability of neurological disease being associated with G 2254 /D 752 strains was 162 times greater than the probability of it being associated with A 2254 /N 752 strains [ 56 ]. Several studies then showed that this genotype/pathotype association is not exclusive [ 21 , 22 , 57 , 58 , 59 ]. The discovery of a third genotype C 2254 /H 752 and its potential association with neurological signs makes the understanding of the genotype/pathotype association even more complex.…”

Section: Discussionmentioning

confidence: 99%

Identification of a New Equid Herpesvirus 1 DNA Polymerase (ORF30) Genotype with the Isolation of a C2254/H752 Strain in French Horses Showing no Major Impact on the Strain Behaviour

Sutton

Thieulent

Fortier

et al. 2020

Viruses

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Equid herpesvirus 1 is one of the most common viral pathogens in the horse population and is associated with respiratory disease, abortion and still-birth, neonatal death and neurological disease. A single point mutation in the DNA polymerase gene (ORF30: A2254G, N752D) has been widely associated with neuropathogenicity of strains, although this association has not been exclusive. This study describes the fortuitous isolation of a strain carrying a new genotype C2254 (H752) from an outbreak in France that lasted several weeks in 2018 and involved 82 horses, two of which showed neurological signs of disease. The strain was characterised as UL clade 10 using the equid herpesvirus 1 (EHV-1) multi-locus sequence typing (MLST) classification but has not been identified or isolated since 2018. The retrospective screening of EHV-1 strains collected between 2016 and 2018 did not reveal the presence of the C2254 mutation. When cultured in vitro, the C2254 EHV-1 strain induced a typical EHV-1 syncytium and cytopathic effect but no significant difference was observed when compared with A2254 and G2254 EHV-1 strains. An experimental infection was carried out on four Welsh mountain ponies to confirm the infectious nature of the C2254 strain. A rapid onset of marked respiratory disease lasting at least 2 weeks, with significant virus shedding and cell-associated viraemia, was observed. Finally, an in vitro antiviral assay using impedance measurement and viral load quantification was performed with three antiviral molecules (ganciclovir (GCV), aciclovir (ACV) and aphidicolin (APD)) on the newly isolated C2254 strain and two other A/G2254 field strains. The three strains showed similar sensitivity to ganciclovir and aphidicolin but both C2254 and A2254 strains were more sensitive to aciclovir than the G2254 strain, based on viral load measurement.

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“…The extent of an outbreak depends on numerous factors, of which some are host related (like age, sex, immune status, concurrent disease, stress level), and others are at country or holding level specific (e.g. animal density, number and conditions of horse movements, biosecurity and control measures applied), while the presence of official notification of EHV‐1, EHV‐1 case definition, horse industry management may also affect the reported outbreak characteristics (Goehring et al, 2006 ; Allen, 2008 ; Perkins et al, 2009 ; Traub‐Dagartz et al, 2013 ; van Galen et al, 2015 ; Pusterla et al, 2016 ; Garvey et al, 2019 ; Dunuwille et al, 2020 ; Pusterla et al, 2020 ).…”

Section: Assessmentmentioning

confidence: 99%

“…In the past, the ability of the virus to cause EHM was thought to be associated with specific EHV‐1 strains, the so‐called neuropathogenic strains, which presented a specific DNA polymerase gene mutation (gene open reading frame 30: G2254/N752). Nevertheless, virus strains without this mutation have been isolated in several outbreaks with horses suffering with neurological signs (Goehring et al, 2006 ; Nugent and Paillot, 2009 ; van Galen et al, 2015 ; Garvey et al, 2019 ; Dunuwille et al, 2020 ; Pusterla et al, 2020 ; Sutton et al, 2020 ; Vereecke et al, 2021 ). For example, the virus causing the most severe EHV‐1 epidemic outbreak in the last decades in Europe with several cases of neurological disease, like the one reported in Valencia at the beginning of 2021, did not belonged to the so‐called neuropathogenic strains and presents the A2254/D752 mutation, as described by Vereecke et al and Sutton et al ( 2021 ).…”

Section: Assessmentmentioning

confidence: 99%

Clinical impact, diagnosis and control of Equine Herpesvirus‐1 infection in Europe

Carvelli¹,

Nielsen²,

Paillot³

et al. 2022

EFS2

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Equine herpesvirus‐1 (EHV‐1) can affect the entire equine sector in EU, and the large outbreak reported in 2021 in Spain drew attention to the needs of the European Commission for scientific advice for the assessment of EHV‐1 infection within the framework of Animal Health Law. EHV‐1 is considered endemic in the EU; its main risk is linked to the characteristic of producing latent life‐long infections. These can reactivate producing clinical disease, which can include respiratory, abortive and possibly fatal neurological forms. From the epidemiological and genomic viewpoint, there are no specific neuropathogenic EHV‐1 strains; the respiratory, reproductive and neurological signs are not found to be strain‐specific. This was also the case of the virus that caused the outbreak in Valencia (Spain) in 2021, which was genetically closely related to other viruses circulating before in Europe, and did not present the so‐called neuropathogenic genotype. The outbreak reported in Valencia was followed by wide geographic spread of the virus possibly due to a delay in diagnosis and late application of biosecurity measures. The recommended and most sensitive diagnostic test for detecting EHV‐1 is PCR performed on swabs collected according to the type of clinical signs. Serological assays on paired blood samples can help to detect a recent infection, while no diagnostic methods are available to detect EHV‐1 latent infections. Safe movements of horses can be ensured at premovement phase by testing and issuing health certificates, and by isolating animals upon arrival at new premises with regular health monitoring. In case of suspicion, movements should be forbidden and EHV‐1 infection early detected/confirmed by validated diagnostic tools. During outbreaks, no movements should be allowed until 21 days after the detection of the last case. In general, vaccination against EHV‐1 should be promoted, although this offers limited protection against the neurological form of the disease.

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Equine herpesvirus-1 genotype did not significantly affect clinical signs and disease outcome in 65 horses diagnosed with equine herpesvirus-1 myeloencephalopathy

Cited by 18 publications

References 12 publications

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): infection with Equine Herpesvirus‐1

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): infection with Equine Herpesvirus‐1

Identification of a New Equid Herpesvirus 1 DNA Polymerase (ORF30) Genotype with the Isolation of a C2254/H752 Strain in French Horses Showing no Major Impact on the Strain Behaviour

Clinical impact, diagnosis and control of Equine Herpesvirus‐1 infection in Europe

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