Genetic variation and dynamics of infections of equid herpesvirus 5 in individual horses

Back, Helena; Ullman, Karin; Leijon, Mikael; Söderlund, Robert; Penell, Johanna; Ståhl, Karl; Pringle, John; Valarcher, J. F.

doi:10.1099/jgv.0.000332

Cited by 11 publications

(14 citation statements)

References 42 publications

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“…A similar correlation has been noted in human cases of IPF with improved response to treatment generally noted in younger patients with less marked disease . The combination of strains or genotypes of EHV‐5 present in a horse with EMPF might have clinical importance; however, further work is necessary to determine whether strain variability is an important component of pathogenicity . In human IPF cases, clinical phenotypes with discrete comorbidities and survival times have been defined.…”

Section: Discussionmentioning

confidence: 75%

Effect of valacyclovir on EHV‐5 viral kinetics in horses with equine multinodular pulmonary fibrosis

Easton-Jones

Madigan

Barnum

et al. 2018

Veterinary Internal Medicne

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BackgroundEquine herpesvirus‐5 is commonly isolated from the lungs of horses with EMPF, suggesting an etiological link. Valacyclovir is used empirically to treat EMPF; however, no data is available concerning its impact on EHV‐5 viral kinetics.ObjectivesTo determine the effect of oral administration of valacyclovir on EHV‐5 viral load measured by qPCR in blood, nasal secretions (NS) and BALF in horses with EMPF.AnimalsSix horses diagnosed with EMPF.MethodsA prospective clinical trial was performed. Horses received 10 days of PO administered valacyclovir (loading dose 30 mg/kg, maintenance dose 20 mg/kg). Blood, NS, and BALF were collected for EHV‐5 viral kinetics analyses during treatment. Blood and NS were collected every other day. BALF was collected on day 0 and day 10.ResultsThere was no statistical difference in median EHV‐5 viral load between day 0 and day 10 for all samples tested. In blood median EHV‐5 viral load was 7676 (range 575‐39 781) on day 0 and 6822 (range 1136‐18 635) glycoprotein B (gB) gene copies per million cells on day 10. For NS median EHV‐5 viral load was 2.944 × 106 (range 184 691‐3.394 × 109) on day 0 and 8.803 × 106 (range 251 186‐9.868 × 108) gB gene copies per million cells on day 10. For BALF median EHV‐5 viral load was 59,842 (range 61‐315 655) on day 0 and 185 083 (range 3562‐542 417) gB gene copies per million cells on day 10.Conclusions and Clinical ImportanceValacyclovir might not be an effective short‐term antiviral treatment but efficacy in treatment of EMPF is unknown.

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Section: Discussionmentioning

confidence: 75%

Effect of valacyclovir on EHV‐5 viral kinetics in horses with equine multinodular pulmonary fibrosis

Easton-Jones

Madigan

Barnum

et al. 2018

Veterinary Internal Medicne

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“…It has been shown previously by several authors that foals can be hosts to more than one genotype of EHV-2 [ 25 ] and EHV-5 [ 27 , 59 ]. Hence, the variability of EHV-2/5 among horses from the same stud (e.g.…”

Section: Discussionmentioning

confidence: 99%

Prevalence and sequence analysis of equid herpesviruses from the respiratory tract of Polish horses

Stasiak

Dunowska

Rola

2018

Virol J

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BackgroundEquid herpesviruses (EHVs) are widespread in equine populations worldwide. While the infection with equine α-herpesviruses (EHV-1 and EHV-4) has been linked to several clinical outcomes, the pathogenic potential for equine γ-herpesviruses (EHV-2 and EHV-5) is still unclear. The objective of the current study was to determine the prevalence of infection with EHVs among Polish horses, to investigate factors associated with EHV infections among horses sampled, and to determine genetic variability within Polish EHV-2 isolates.MethodsVirus-specific real-time PCR assays were used for detection of EHV-1, EHV-2, EHV-4 and EHV-5 in nasal swabs collected from 540 horses from 13 national horse studs located throughout Poland. A proportion of EHV-2/5 positive samples were subjected to virus isolation followed by amplification and analysis of partial glycoprotein B sequence.ResultsOverall, 448/540 (83.0%) horses sampled were positive for at least one virus. The most prevalent was infection with EHV-2 (77.2%), followed by EHV-5 (47.0%), and EHV-4 (0.4%). None of the horses was positive for EHV-1. Approximately half of the virus-infected horses were positive for both EHV-2 and EHV-5. The proportion of EHV-2/5 positive horses varied by age, breed, and season. Only 8.0% of horses sampled, mostly Arabians, showed clinical signs of respiratory disease at the time of sampling. The viral load of both EHV-2 and EHV-5 DNA was highest in swabs from young horses, which was particularly evident for EHV-2 infected foals. Mean viral loads in nasal swabs collected from diseased horses were higher than in swabs from healthy horses. That was also true for EHV-2 when only diseased Arabian foals were considered, but the levels of EHV-5 DNA were lower in swabs from diseased than from healthy foals. In agreement with other studies, there was a considerable variability between Polish EHV-2 sequences, with no clustering of sequences from horses with different health status. The level of EHV-2 variability seemed to differ between different studs/breeds.ConclusionsThe presence of foals and yearlings on a property is likely to increase the risk of active EHV-2/5 infection among in-contact horses. The existence of breed-specific differences in susceptibility to EHV-2/5 infections should be further investigated, as it may provide one variable that needs to be considered in attempts to associate EHV-2/5 infections with disease. Overall, the data presented add to the existing knowledge of the epidemiology and biology of equine γ-herpesviruses, with the long-term goal of better understanding of the pathogenesis and the impact of infections with these viruses on the well-being of the horse.

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“…Temporal heterogeneity or fibroblast foci, hallmarks of human disease, are not present in the disease in horses, though these characteristics have been described in feline pulmonary fibrosis ( 111 , 112 ). Similar to EBV in humans, which has been associated with IPF, EHV 5 is a ubiquitous subclinical gammaherpesviral infection in horses ( 113 ). Considered largely non-pathogenic in the natural host, some strains of EHV5 appear to be pathogenic and capable of inducing lung fibrosis ( 103 ).…”

Section: Domestic Animalsmentioning

confidence: 99%

Exploring Animal Models That Resemble Idiopathic Pulmonary Fibrosis

Tashiro¹,

Rubio²,

Limper³

et al. 2017

Front. Med.

228

223

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Large multicenter clinical trials have led to two recently approved drugs for patients with idiopathic pulmonary fibrosis (IPF); yet, both of these therapies only slow disease progression and do not provide a definitive cure. Traditionally, preclinical trials have utilized mouse models of bleomycin (BLM)-induced pulmonary fibrosis—though several limitations prevent direct translation to human IPF. Spontaneous pulmonary fibrosis occurs in other animal species, including dogs, horses, donkeys, and cats. While the fibrotic lungs of these animals share many characteristics with lungs of patients with IPF, current veterinary classifications of fibrotic lung disease are not entirely equivalent. Additional studies that profile these examples of spontaneous fibroses in animals for similarities to human IPF should prove useful for both human and animal investigators. In the meantime, studies of BLM-induced fibrosis in aged male mice remain the most clinically relevant model for preclinical study for human IPF. Addressing issues such as time course of treatment, animal size and characteristics, clinically irrelevant treatment endpoints, and reproducibility of therapeutic outcomes will improve the current status of preclinical studies. Elucidating the mechanisms responsible for the development of fibrosis and disrepair associated with aging through a collaborative approach between researchers will promote the development of models that more accurately represent the realm of interstitial lung diseases in humans.

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Genetic variation and dynamics of infections of equid herpesvirus 5 in individual horses

Cited by 11 publications

References 42 publications

Effect of valacyclovir on EHV‐5 viral kinetics in horses with equine multinodular pulmonary fibrosis

Effect of valacyclovir on EHV‐5 viral kinetics in horses with equine multinodular pulmonary fibrosis

Prevalence and sequence analysis of equid herpesviruses from the respiratory tract of Polish horses

Exploring Animal Models That Resemble Idiopathic Pulmonary Fibrosis

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