Equine Herpesvirus Research Articles

EPIZOOTOLOGICAL MONITORING OF EQUINE HERPESVIRUS IN KAZAKHSTAN

Equine herpesvirus is one of the most common infectious diseases of horses, causing huge economic losses associated with fetal abortion and subsequent chronic course. At the same time, a difficult epizootological situation regarding herpesvirus infections remains in the republic. Therefore, epizootological surveillance and planned monitoring studies of the epidemiological process in a certain territory are one of the effective tools for preventing the spread of еquine herpesvirus in horse breeding farms. This article presents the results of an analysis of epizootological monitoring and ongoing diagnostic measures regarding еquine herpesvirus on the territory of the Republic of Kazakhstan. According to epizootological data, over the past 10 years, 35 outbreaks of еquine herpesvirus have been registered in Kazakhstan. Serological monitoring confirmed the circulation of the causative agent of equine herpesvirus in the country's horse breeding farms. In a study of 1391 blood serum samples, antibodies to equine herpesvirus were detected in 93 cases (6.7%). The data obtained give reason to believe that in disadvantaged areas it is necessary to take a full range of measures for timely diagnosis, prevention and elimination of foci of infection.

Hyperoside inhibits EHV-8 infection via alleviating oxidative stress and IFN production through activating JNK/Keap1/Nrf2/HO-1 signaling pathways.

Equine herpesvirus type 8 (EHV-8) causes abortion and respiratory disease in horses and donkeys, leading to serious economic losses in the global equine industry. Currently, there is no effective vaccine or drug against EHV-8 infection, underscoring the need for a novel antiviral drug to prevent EHV-8-induced latent infection and decrease the pathogenicity of this virus. The present study demonstrated that hyperoside can exert antiviral effects against EHV-8 infection in RK-13 (rabbit kidney cells), MDBK (Madin-Darby bovine kidney), and NBL-6 cells (E. Derm cells). Mechanistic investigations revealed that hyperoside induces heme oxygenase-1 expression by activating the c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis, alleviating oxidative stress and triggering a downstream antiviral interferon response. Accordingly, hyperoside inhibits EHV-8 infection. Meanwhile, hyperoside can also mitigate EHV-8-induced injury in the lungs of infected mice. These results indicate that hyperoside may serve as a novel antiviral agent against EHV-8 infection.IMPORTANCEHyperoside has been reported to suppress viral infections, including herpesvirus, hepatitis B virus, infectious bronchitis virus, and severe acute respiratory syndrome coronavirus 2 infection. However, its mechanism of action against equine herpesvirus type 8 (EHV-8) is currently unknown. Here, we demonstrated that hyperoside significantly inhibits EHV-8 adsorption and internalization in susceptible cells. This process induces HO-1 expression via c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis activation, alleviating oxidative stress and triggering an antiviral interferon response. These findings indicate that hyperoside could be very effective as a drug against EHV-8.

Equine gamma herpesvirus presence and viral load are not associated with equine glandular gastric disease.

To investigate the role of equine herpesvirus-2 (EHV-2) and equine herpesvirus-5 (EHV-5) in equine glandular gastric disease (EGGD) by visualizing and quantifying these gamma herpesviruses in EGGD-affected and normal glandular gastric mucosa of horses. A secondary objective was to describe the histopathological abnormalities in the equine gastric glandular mucosa in horses with EGGD. 29 horses (n = 21 postmortem and 8 gastroscopy) categorized as normal (11), EGGD (12), or both EGGD and equine squamous gastric disease (6). Glandular gastric mucosal samples were collected from horses by gastroscopy or postmortem. Histopathology and in situ hybridization targeting EHV-2 and EHV-5 were performed on grossly normal and abnormal glandular gastric mucosa. The number of in situ hybridization-positive cells per millimeter squared of tissue was calculated. Evaluators were blinded to groups. Glandular gastric tissues from horses without EGGD had higher viral loads in the mucosa than normal or abnormal tissues from EGGD horses. There was no difference in viral loads for EHV-2 or EHV-5 between grossly or endoscopically normal to abnormal gastric tissues within horses with EGGD. Lymphocytic plasmacytic gastritis was the most common histopathological abnormality, with only 3 horses having mucosal disruption (glandular ulcer or erosion). Equine gamma herpesviruses are unlikely to play a role in the pathophysiology of EGGD. EGGD is frequently inflammatory with occasional mucosal disruption (ulcer or erosion).

Updated ACVIM consensus statement on equine herpesvirus-1.

Equine herpesvirus-1 (EHV-1) is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). The previous consensus statement was published in 2009 and considered pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment. A recent survey of American College of Veterinary Internal Medicine large animal diplomates identified the need for a revision to this original consensus statement. This updated consensus statement is underpinned by 4 systematic reviews that addressed key questions concerning vaccination, pharmaceutical treatment, pathogenesis, and diagnostic testing. Evidence for successful vaccination against, or effective treatment of EHV-1 infection was limited, and improvements in experimental design and reporting of results are needed in future studies of this important disease. This consensus statement also updates the topics considered previously in 2009.

Modulation of Equid Herpesvirus-1 Replication Dynamics In Vitro Using CRISPR/Cas9-Assisted Genome Editing.

(1) Background: equid alphaherpesvirus-1 (EHV-1) is a highly contagious viral pathogen prevalent in most horse populations worldwide. Genome-editing technologies such as CRISPR/Cas9 have become powerful tools for precise RNA-guided genome modifications; (2) Methods: we designed single guide RNAs (sgRNA) to target three essential (ORF30, ORF31, and ORF7) and one non-essential (ORF74) EHV-1 genes and determine their effect on viral replication dynamics in vitro; (3) Results: we demonstrated that sgRNAs targeting essential lytic genes reduced EHV-1 replication, whereas those targeting ORF74 had a negligible effect. The sgRNAs targeting ORF30 showed the strongest effect on the suppression of EHV-1 replication, with a reduction in viral genomic copy numbers and infectious progeny virus output. Next-generation sequencing identified variants with deletions in the specific cleavage site of selective sgRNAs. Moreover, we evaluated the combination between different sgRNAs and found that the dual combination of sgRNAs targeting ORF30 and ORF7 significantly suppressed viral replication to lower levels compared to the use of a single sgRNA, suggesting a synergic effect; (4) Conclusion: data demonstrate that sgRNA-guided CRISPR/Cas9 can be used to inhibit EHV-1 replication in vitro, indicating that this programmable technique can be used to develop a novel, safe, and efficacious therapeutic and prophylactic approach against EHV-1.

Heme oxygenase-1 is an equid alphaherpesvirus 8 replication restriction host protein and suppresses viral replication via the PKCβ/ERK1/ERK2 and NO/cGMP/PKG pathway.

Equid alphaherpesvirus 8 (EqHV-8) is one of the most economically important viruses that is known to cause severe respiratory disease, abortion, and neurological syndromes in equines. However, no effective vaccines or therapeutic agents are available to control EqHV-8 infection. Heme oxygenase-1 (HO-1) is an antioxidant defense enzyme that displays significant cytoprotective effects against different viral infections. However, the literature on the function of HO-1 during EqHV-8 infection is little. We explored the effects of HO-1 on EqHV-8 infection and revealed its potential mechanisms. Our results demonstrated that HO-1 induced by cobalt-protoporphyrin (CoPP) or HO-1 overexpression inhibited EqHV-8 replication in susceptible cells. In contrast, HO-1 inhibitor (zinc protoporphyria) or siRNA targeting HO-1 reversed the anti-EqHV-8 activity. Furthermore, biliverdin, a metabolic product of HO-1, mediated the anti-EqHV-8 effect of HO-1 via both the protein kinase C (PKC)β/extracellular signal-regulated kinase (ERK)1/ERK2 and nitric oxide (NO)-dependent cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG) signaling pathways. In addition, CoPP protected the mice by reducing the EqHV-8 infection in the lungs. Altogether, these results indicated that HO-1 can be developed as a promising therapeutic strategy to control EqHV-8 infection.IMPORTANCEEqHV-8 infections have threatened continuously donkey and horse industry worldwide, which induces huge economic losses every year. However, no effective vaccination strategies or drug against EqHV-8 infection until now. Our present study found that one host protien HO-1 restrict EqHV-8 replication in vitro and in vivo. Furthermore, we demonstrate that HO-1 and its metabolite biliverdin suppress EqHV-8 relication via the PKCβ/ERK1/ERK2 and NO/cGMP/PKG pathways. Hence, we believe that HO-1 can be developed as a promising therapeutic strategy to control EqHV-8 infection.

Seroprevalence and associated risk factors of equine herpesvirus type-1/-4 in selected districts of Northwest Amhara, Ethiopia

This study aimed to estimate the prevalence, determine the distribution, and identify the epidemiological risk factors of EHV-1/-4 infections in selected districts of Northwest Amhara Region. 460 serum samples were collected from equines using multistage cluster sampling technique, and a competitive Enzyme-linked immunosorbent assay (cELISA) was performed. Various risk factors for the occurrence of EHV-1/-4 were considered. Statistical analysis was performed using R version 4.3.1. 65.9% (303) equids were tested positive for antibodies against EHV-1/-4. Based on district, the highest prevalence was recorded in Wogera (86.1%), while the lowest was in Debark (47.4%). There was a significant difference (p <0.05; 95% CI: 1.1067993–3.682843) in the prevalence of EHV-1/-4 among species and donkeys are 2.019 times more likely to get an EHV infection than horses. The prevalence of EHV-1/-4 was highest in equids with the age of 3–8 years and lowest in < 3 years, and the difference was statistically significant (p <0.05; 95% CI: 1.9812042–6.771820). Statistically significant variation (p <0.05; 95% CI: 1.1173822–2.684013) was also observed between sex of equids in which females had 1.73 times higher chance to get EHV infection than males. Higher prevalence was found in lactating equids (81.6%), followed by pregnant equids (74.6%), and dry equids (66.4%). Generally, this study indicated a high and wide distribution of EHV-1/-4 infection in the study area, which needs due attention. Devising strategies to prevent and minimize the spread and occurrence of the infection is crucial.

Identification of neuropathogenic Varicellovirus equidalpha1 as a potential cause of respiratory disease outbreaks among horses in North Xinjiang, China, from 2021-2023.

Varicellovirus equidalpha1 (formerly Equid alphaherpesvirus 1, EqAHV-1) is among the most important viruses responsible for respiratory disease outbreaks among horses throughout the world. No reports to date have detailed the association between EqAHV-1 and respiratory disease among horses in China. This study described one such outbreak among a population of horses in north Xinjiang that occurred from April 2021 - May 2023. qPCR revealed that EqAHV-1 was detectable in all samples and this virus was identified as a possible source of respiratory disease, although a limited subset of these samples were also positive for EqAHV-2, EqAHV-4, and EqAHV-5. In total, three EqAHV-1 strains responsible for causing respiratory illness in horses were isolated successfully, and full-length ORF33 sequence comparisonsand phylogenetic analyses indicated that these isolates may have originated from EqAHV-1 strains detected in Yili horse abortions. ORF30 sequence data additionally suggested that these strains were neuropathic, as evidenced by the presence of a guanine residue at nucleotide position 2254 corresponding to the aspartic acid present at position 752 in the DNA polymerase encoded by this virus. This study is the first report of an outbreak of respiratory disease among horses in China caused by EqAHV-1. ORF30 sequence characterization revealed that these EqAHV-1 strains harbored a neuropathogenic genotype. Given the detection of this virus in horses suffering from respiratory disease, concern is warranted with respect to this neuropathogenic EqAHV-1 outbreak.

The transmembrane and cytosolic domains of equine herpesvirus type 1 glycoprotein D determine Golgi retention by regulating vesicle formation

Accumulating evidence underscores the pivotal role of envelope proteins in viral secondary envelopment. However, the intricate molecular mechanisms governing this phenomenon remain elusive. To shed light on these mechanisms, we investigated a Golgi-retained gD of EHV-1 (gDEHV-1), distinguishing it from its counterparts in Herpes Simplex Virus-1 (HSV-1) and Pseudorabies Virus (PRV). To unravel the specific sequences responsible for the Golgi retention phenotype, we employed a gene truncation and replacement strategy. The results suggested that Golgi retention signals in gDEHV-1 exhibiting a multi-domain character. The extracellular domain of gDEHV-1 was identified as an endoplasmic reticulum (ER)-resident domain, the transmembrane domain and cytoplasmic tail (TM-CT) of gDEHV-1 were integral in facilitating the protein's residence within the Golgi complex. Deletion or replacement of either of these dual domains consistently resulted in the mutant gDEHV-1 being retained in an ER-like structure. Moreover, (TM-CT)EHV-1 demonstrated a preference for binding to endomembranes, inducing the generation of a substantial number of vesicles, potentially originate from the Golgi complex or the ER-Golgi intermediate compartment. In conclusion, our findings provide insights into the intricate molecular mechanisms governing the Golgi retention of gDEHV-1, facilitating the comprehension of the processes underlying viral secondary envelopment.

Investigation of the presence of equine herpesvirus-1 (EHV-1) in tissue samples of aborted foals by histopathological, immunohistochemical, and Real-Time PCR techniques

Equine herpesvirus-1 (EHV-1) is a cause of pneumonia, encephalitis, and abortion in horses. Abortions occur alive or dead in the last trimester of pregnancy. The aim of this study is to investigate the incidence of EHV-1 infections in the tissue samples of aborted stillborn and live-born foals and the foals which died soon after birth and compare and correlate the conventional histopathologic diagnosis with IHC and Real-Time PCR. For this purpose, tissue samples (lung, liver, spleen, kidney, placenta, and brain) of 38 foals from Istanbul, Kocaeli, Bursa, and Eskişehir provinces of Turkey between August 2009 and March 2011 were examined Real-Time PCR revealed 52.6 % positivity (20/38), whereas 39.4 % (15/38) positivity was achieved with IHC, which indicated a correlation between these two diagnostic methods. In histopathological evaluation, the inclusion body was found in at least one of the tissue sections belonging to the lung, spleen, and mostly liver of 20 foals (52.6%). Tissue samples of the foals found to be positive by IHC and PCR revealed histopathologic findings compatible with the characteristics of the disease.

Equine herpesvirus 4 infected domestic horses associated with Sintashta spoke-wheeled chariots around 4,000 years ago.

Equine viral outbreaks have disrupted the socio-economic life of past human societies up until the late 19th century and continue to be of major concern to the horse industry today. With a seroprevalence of 60-80 per cent, equine herpesvirus 4 (EHV-4) is the most common horse pathogen on the planet. Yet, its evolutionary history remains understudied. Here, we screen the sequenced data of 264 archaeological horse remains to detect the presence of EHV-4. We recover the first ancient EHV-4 genome with 4.2× average depth-of-coverage from a specimen excavated in the Southeastern Urals and dated to the Early Bronze Age period, approximately 3,900 years ago. The recovery of an EHV-4 virus outside the upper respiratory tract not only points to an animal particularly infected but also highlights the importance of post-cranial bones in pathogen characterisation. Bayesian phylogenetic reconstruction provides a minimal time estimate for EHV-4 diversification to around 4,000 years ago, a time when modern domestic horses spread across the Central Asian steppes together with spoke-wheeled Sintashta chariots, or earlier. The analyses also considerably revise the diversification time of the two EHV-4 subclades from the 16th century based solely on modern data to nearly a thousand years ago. Our study paves the way for a robust reconstruction of the history of non-human pathogens and their impact on animal health.

Recent sequencing and phylogenetic analysis of equine herpesviruses 1 and 4 among different equine populations in Egypt.

Equine herpes viruses (EHVs) are considered one of the most important respiratory pathogens in equids, resulting in serious outcomes for equine health worldwide. The objectives of the current research were the detection, molecular characterization, and isolation of EHV-1 and EHV-4 circulating within different equine populations in Egypt, either clinically or in apparently healthy horses. A total of 120 field samples were collected, and DNA was extracted. Screening and typing of extracted DNA were done by consensus and conventional PCR assays for detection of EHV-1 and EHV-4, followed by sequencing and phylogenetic analysis to confirm the virus identity. Selected positive samples for both EHV-1 and EHV-4 were subjected to Madin-Darby bovine kidney (MDBK) cell lines for virus isolation. The obtained results revealed that 58/120 (48%) samples were positive for EHVs. Typing of positive samples showed that EHV-1 was detected in (48/120) 40% of samples and EHV-4 was detected in (15/120) 12% of samples, while dual infection by both EHV-1 and 4 was detected in five samples. The current study revealed new data on the continuous circulation of EHV-1 and EHV-4 within equine populations in Egypt, and individual horses could be infected by multiple EHVs. In addition, latently infected horses are acting as potential reservoirs for frequent virus reactivation.

Compulsory vaccination against Equine Herpes Virus-1 (EHV-1) infection – A critical appraisal of the compulsory vaccination stipulated by horse sport organisations in Germany

Compulsory vaccination against Equine Herpes Virus-1 (EHV-1) infection – A critical appraisal of the compulsory vaccination stipulated by horse sport organisations in Germany

Анализ вакцин против ринопневмонии лошадей отечественного и зарубежного производства

Equine rhinopneumonia is caused by two closely related viruses of the Herpesviridae family: equine herpesvirus-1 and equine herpesvirus-4 (EHV-1 and EHV-4). The disease is manifested by decreased performance of animals, in neglected cases by severe respiratory disease, abortion and paralysis. Outbreaks of rhinopneumonia have a negative impact on the livestock industry. A number of vaccines have been developed worldwide to prevent and control the infection. Despite the seriousness of the disease there are currently only a few well-studied strains of the virus that are the mainstay of vaccine development. Due to the dramatic increase in the number of rhinopneumonia outbreaks around the world, scientists have recently been faced with the need to isolate new strains of the virus. However, the creation of polyvalent associated vaccines has not yet yielded the desired results. The review article presents a comparison of domestic preparations with foreign ones. Analysis of the considered sources, based on the scientific achievements of foreign researchers, allows us to form a modern idea of the degree of preparation for the fight against infectious viral disease.

Antibody reactions of horses against various domains of the EHV-1 receptor-binding protein gD1.

Equid alphaherpesviruses 1 (EHV-1) and 4 (EHV-4) are closely related and both endemic in horses worldwide. Both viruses replicate in the upper respiratory tract, but EHV-1 may additionally lead to abortion and equine herpesvirus myeloencephalopathy (EHM). We focused on antibody responses in horses against the receptor-binding glycoprotein D of EHV-1 (gD1), which shares a 77% amino acid identity with its counterpart in EHV-4 (gD4). Both antigens give rise to cross-reacting antibodies, including neutralizing antibodies. However, immunity against EHV-4 is not considered protective against EHM. While a diagnostic ELISA to discriminate between EHV-1 and EHV-4 infections is available based on type-specific fragments of glycoprotein G (gG1 and gG4, respectively), the type-specific antibody reaction against gD1 has not yet been sufficiently addressed. Starting from the N-terminus of gD1, we developed luciferase immunoprecipitation system (LIPS) assays, using gD1-fragments of increasing size as antigens, i.e. gD1_83 (comprising the first 83 amino acids), gD1_160, gD1_180, and gD1_402 (the full-length molecule). These assays were then used to analyse panels of horse sera from Switzerland (n = 60) and Iceland (n = 50), the latter of which is considered EHV-1 free. We detected only one true negative horse serum from Iceland, whereas all other sera in both panels were seropositive for both gG4 (ELISA) and gD1 (LIPS against gD1_402). In contrast, seropositivity against gG1 was rather rare (35% Swiss sera; 14% Icelandic sera). Therefore, a high percentage of antibodies against gD1 could be attributed to cross-reaction and due to EHV-4 infections. In contrast, the gD1_83 fragment was able to identify sera with type-specific antibodies against gD1. Interestingly, those sera stemmed almost exclusively from vaccinated horses. Although it is uncertain that the N-terminal epitopes of gD1 addressed in this communication are linked to better protection, we suggest that in future vaccine developments, type-common antigens should be avoided, while a broad range of type-specific antigens should be favored.

Molecular Detection of Equine Herpesviruses from Field Outbreaks in Donkeys in Northwest Amhara Region, Ethiopia.

Equine herpesviruses pose a threat to equine health and potentially cause substantial economic losses to the global equine industry. EHV outbreaks have been reported in various parts of Ethiopia and the Amhara region specifically. This study aimed to detect EHVs from suspected outbreak cases in selected districts of the Northwest Amhara region. A cross-sectional study was performed from January 2022 to July 2022 to detect EHVs from suspected outbreak cases. Clinical observation was conducted for the presumptive identification of equine herpesvirus infection, and nasopharyngeal swab samples were collected for molecular detection of the viruses for confirmation. Out of 463 donkeys observed, 23 donkeys showed clinical signs suggestive of equine herpesvirus infection. Samples from 10 suspected donkeys were further subjected to polymerase chain reaction (PCR) test, amplifying ORF30 for EHV-1 and gB for EHV-2 and EHV-5. Among the 10 donkeys tested, seven (n = 7) were positive for EHV-5. All ten (n = 10) tested donkeys were negative for EHV-1 and EHV-2. EHV-5 was detected in animals with nervous signs, respiratory signs, a combination of nervous and respiratory signs, and a combination of abortion, respiratory, and nervous signs. Generally, only EHV-5 was identified from the outbreak, and more detailed epidemiological/molecular studies should be performed to better understand its dynamics and inform preventive measures.

Attenuation of the neuropathogenic equine herpesvirus type 1 strain Ab4p in hamsters by a single amino acid mutation (D752N) in viral DNA polymerase ORF30.

Equine herpesvirus type 1 (EHV-1) causes abortion, respiratory infection, and neurological diseases (equine herpesvirus myeloencephalopathy) in horses. A single nucleotide polymorphism (SNP) associated with a single amino acid in the DNA polymerase gene (ORF30, in which D752 is neuropathogenic and N752 is non-neuropathogenic) of EHV-1 has been associated with neuropathogenicity in horses. We constructed an EHV-1 Ab4p ORF30 N752 mutant and a repair virus to examine the effect of a D752N mutation on the neuropathogenicity of the virus in Syrian hamsters. The N752 mutation did not affect viral growth in cultured cells but it did attenuate the neuropathogenicity of Ab4p in the hamsters. The results suggest that D752N is involved in neuropathogenicity not only in horses but also in hamsters.

Molecular characterization of equine herpes viruses type 1 and 4 among Arabian horse populations in Egypt during the period between 2021 and 2022.

Equine herpesvirus type 1 (EHV-1) is a major cause of abortion and respiratory disease. Equine herpesvirus type 4 (EHV-4), on the other hand, is exclusively associated with respiratory disease in horse populations worldwide, particularly in Egypt and Arabian countries. This study aims to investigate the circulation of EHV-1 and EHV-4 in the Arabian horse population through molecular detection and genetic characterization of EHV-1 and/or EHV-4 that may threaten the stability of horse industry. A total of 80 samples including 50 nasal swabs, 10 vaginal swabs and 20 whole blood samples were collected from vaccinated and registered pure-bred Arabian adult horses from different studs in the governorates of northern Egypt (Cairo, Dakahlyia and Qalyubia) from 2021 to 2022. The collected samples were screened using consensus PCR for detection of EHVs using specific primers targeting DNA polymerase gene. The positive samples were subjected to conventional PCR for detection of EHV-1 and/or EHV-4using specific primers targeting glycoprotein (gB) gene. EHV-1 and EHV-4 amplicons were partially sequenced and phylogenetically analyzed using Sanger method. Consensus PCR revealed that 48 out of 80 samples were positive for EHVs with percentage of 60%. Typing of the selected positive samples using conventional PCR showed that 29 out of 80 were positive for EHV-1 with percentage 36.25%, while 24 out of 80 samples were positive for EHV-4 with percentage 30%. Mixed infections with both viruses were detected in five samples. The amplified products were sequenced using Sanger method and submitted to GenBank under accession number OM362231MG-1 for EHV-1 strain and OM362232 MG-4 for EHV-4 strain. Sequence analysis and alignments of the amplified fragments of the EHV-1 and EHV-4 glycoprotein B (gB) gene to that of GenBank-derived reference strains revealed a high degree of similarity. According to the phylogenetic tree, the obtained sequences of EHV-1 and 4 in the current study showed homogeneity with local Egyptian and foreign EHV-1 and 4 strains and heterogeneity with EHV-2 and 5. The current investigation showed that molecular methods are appropriate assays for an efficient and accurate diagnosis of EHVs. Furthermore, it supports earlier research findings about the prevalence of EHV-1 and 4 in Arabian horse populations in Egypt.

Герпесвирусная инфекция у лошадей в Казахстане

For horse breeding in many countries of the world, herpesvirus infections are a constant threat, primarily equine herpesvirus infection (rhinopneumonia–viral abortion of horses). In the course of the work, an epizootological analysis of the situation on the territory of the country and the world over the past 10 years – from 2014 to 2023, is carried out. As a result of the conducted research, the epizootological characteristics of the territory of the Republic of Kazakhstan for the last 10 years on horse rhinopneumonia were determined, zoning and regionalization of the territory of the Republic of Kazakhstan were carried out according to the degree of intensity of the epizootic situation on horse rhinopneumonia. The spread of rhinopneumonia among horses in various regions, as well as the identification of factors contributing to its transmission

Lymphocytic myenteric ganglionitis associated with equine herpesvirus infection: A cause of chronic intestinal pseudo‐obstruction and recurrent colic in an adult horse

SummaryThis report describes a rare case of chronic intestinal pseudo‐obstruction (CIPO) in a 12‐year‐old Quarter Horse gelding, caused by lymphocytic myenteric ganglionitis (MG) associated with equine herpesvirus 1 (EHV‐1) and equine herpesvirus 5 (EHV‐5) infection. The horse presented with recurrent colic and weight loss over 1.5 years. Repetitive transrectal examinations consistently revealed small colon impaction and enlargement. During postmortem examination alternating segments of enlarged and reduced luminal diameter were observed throughout the entire intestinal tract. MG with lymphocytic infiltrates and neuronal degeneration of the large intestine were found on histopathological analysis. Additionally, polymerase chain reaction (PCR) analysis confirmed the presence of EHV‐1 and EHV‐5 DNA in affected intestinal tissues. Further research is needed to understand the pathophysiology of MG and its association with herpesviruses. Early recognition and diagnosis of MG‐associated CIPO may improve treatment approaches and outcomes for future cases.