Detection of equid herpesviruses among different Arabian horse populations in Egypt.
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ABSTRACT:
SUBMITTER: Azab W
PROVIDER: S-EPMC7155215 | biostudies-literature | 2019 Aug
REPOSITORIES: biostudies-literature
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Project description:Equid herpesviruses (EHVs) are pathogens of equid and nonequid hosts that can cause disease and fatalities in captivity and in the wild. EHVs establish latent infections but can reactivate, and most EHVs are shed via the nasal passage. Therefore, nasal swabs are generally used for EHV monitoring. However, invasive sampling of wild equids is difficult. While feces is a commonly used substrate for detecting other pathogens, to our knowledge, EHVs have never been detected in feces of naturally infected equids. We systematically tested zebra feces for EHV presence by (i) establishing nested PCR conditions for fecal DNA extracts, (ii) controlling for environmental EHV contamination, and (iii) large-scale testing on a free-ranging zebra population. A dilution minimizing inhibition while maximizing viral DNA concentrations was determined in captive Grévy's zebra (Equus grevyi) fecal samples from individuals shedding EHV nasally. Sixteen of 42 fecal samples (38%) were EHV positive. To demonstrate that the EHV positivity was not a result of environmental contamination, rectal swabs of wild zebras were screened (n?=?18 [Equus quagga and E. zebra]), and 50% were EHV positive, indicating that the source of EHV in feces is likely the intestinal mucosa and not postdefecation contamination. Out of 270 fecal samples of wild zebras, 26% were EHV positive. Quantitative PCRs showed that the amount of virus DNA in feces was not significantly smaller than that in other samples. In summary, fecal sampling facilitates large-scale screening and may be useful to noninvasively investigate phylogenetic EHV diversity in wild and domestic equids.IMPORTANCE Equid herpesviruses (EHVs) establish latent infections, and many EHVs are shed and transmitted via nasal discharge primarily through droplet and aerosol infection. Obtaining nasal swabs and other invasive samples from wildlife is often not possible without capture and physical restraint of individuals, which are resource intensive and a health risk for the captured animals. Fecal EHV shedding has never been demonstrated for naturally infected equids. We established the conditions for fecal EHV screening, and our results suggest that testing fecal samples is an effective noninvasive approach for monitoring acute EHV shedding in equids.
| S-EPMC6344631 | biostudies-literature
Project description:Horses are one of the early domesticated animals in the world that changed societies and civilizations on a continent-wide scale. Due to the rare information about the genetic characterization of different horse populations in Egypt, this study aimed to identify the genetic biodiversity and relationships between four horse populations reared in Egypt. Genomic DNA was extracted and mtDNA region was amplified using polymerase chain reaction (PCR). The alignment of 384-bp amplified fragments showed the presence of 41 polymorphic sites resulting in 29 haplotypes which their sequences were submitted to GenBank under the accession numbers: KX909898-KX909926. The phylogeny tree for tested horses declared the presence of mixing maternal lineages between the four tested populations but still there are some separated lineages especially for Arabian and Thoroughbred horses. The sequences of 72 tested sequences were aligned with 13 published sequences as references, 11 of them for different Equus caballus whereas the other two reference sequences for Equus burchellii and Equus asinus. The results showed that all tested horses from the four populations are grouped with reference sequences of Equus caballus and separated from the other two reference sequences of Equus burchellii and Equus asinus. It is concluded that sequence analysis of mtDNA control region is still the most informative tool for the identification of genetic biodiversity and phylogeny of different horse breeds and populations. The horse populations reared in Egypt possess low genetic diversity and all of them are belonged to Equus caballus breed.
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Project description:We resequenced the genome of equid herpesvirus 2 (EHV2) strain 86/67 and sequenced the genomes of EHV2 strain G9/92 and equid herpesvirus 5 (EHV5) strain 2-141/67. The most prominent genetic differences are the dissimilar locations of the interleukin-10 (IL-10)-like genes and the presence of an OX-2-like gene in EHV5 only.
| S-EPMC4357765 | biostudies-literature
Project description:The present research aimed to characterize the Persian Kurdish horse population relative to the Persian Arabian and American Thoroughbred populations using genome-wide SNP data. Fifty-eight Kurdish, 38 Persian Arabian and 83 Thoroughbred horses were genotyped across 670,796 markers. After quality control and pruning to eliminate linkage disequilibrium between loci which resulted in 13,554 SNPs in 52 Kurdish, 24 Persian Arabian and 58 Thoroughbred horses, the Kurdish horses were generally distinguished from the Persian Arabian samples by Principal Component Analyses, cluster analyses and calculation of pairwise FST. Both Persian breeds were discriminated from the Thoroughbred. Pairwise FST between the two Persian samples (0.013) was significantly greater than zero and several fold less than those found between the Thoroughbred and Kurdish (0.052) or Thoroughbred and Persian Arabian (0.057). Cluster analysis assuming three genetic clusters assigned the Kurdish horse and Thoroughbred to distinct clusters (0.942 in cluster 2 and 0.953 in cluster 3 respectively); the Persian Arabian was not in a distinct cluster (0.519 in cluster 1), demonstrating shared ancestry or recent admixture with the Kurdish breed. Diversity as quantified by expected heterozygosity was the highest in the Kurdish horse (0.342), followed by the Persian Arabian (0.328) and the Thoroughbred (0.326). Analysis of Molecular Variance showed that 4.47% of the genetic variation was present among populations (P<0.001). Population-specific inbreeding indices (FIS) were not significantly different from zero in any of the populations. Analysis of individual inbreeding based on runs of homozygosity using a larger SNP set suggested greater diversity in both the Kurdish and Persian Arabian than in the Thoroughbred. These results have implications for developing conservation strategies to achieve sound breeding goals while maintaining genetic diversity.
| S-EPMC7886144 | biostudies-literature
Project description:Equid herpesvirus (EHV) is a contagious viral disease affecting horses, causing illness characterized by respiratory symptoms, abortion and neurological disorders. It is common worldwide and causes severe economic losses to the equine industry. The present study was aimed at investigating the incidence of EHVs, the genetic characterization of Tunisian isolates and a spatiotemporal study, using 298 collected samples from diseased and clinically healthy horses. The global incidence of EHV infection was found to be about 71.81%. EHV2 and EHV5 were detected in 146 (48.99%) and 159 (53.35%) sampled horses, respectively. EHV1 was detected in 11 samples (3.69%); EHV4 was not detected. Co-infections with EHV1-EHV2, EHV1-EHV5 and EHV2-EHV5 were observed in 0.33%, 1.34% and 31.54% of tested horses, respectively. Phylogenetic analyses showed that gB of EHV2 and EHV5 displays high genetic diversity with a nucleotide sequence identity ranging from 88 to 100% for EHV2 and 97.5 to 100% for EHV5. Phylogeography suggested Iceland and USA as the most likely countries of origin of the Tunisian EHV2 and EHV5 isolates. These viruses detected in Tunisia seemed to be introduced in the 2000s. This first epidemiological and phylogeographic study is important for better knowledge of the evolution of equid herpesvirus infections in Tunisia.
| S-EPMC9504996 | biostudies-literature
Project description:BackgroundMaternal inheritance is an essential point in Arabian horse population genetics and strains classification. The mitochondrial DNA (mtDNA) sequencing is a highly informative tool to investigate maternal lineages. We sequenced the whole mtDNA D-loop of 251 Arabian horses to study the genetic diversity and phylogenetic relationships of Arabian populations and to examine the traditional strain classification system that depends on maternal family lines using native Arabian horses from the Middle East.ResultsThe variability in the upstream region of the D-loop revealed additional differences among the haplotypes that had identical sequences in the hypervariable region 1 (HVR1). While the American-Arabians showed relatively low diversity, the Syrian population was the most variable and contained a very rare and old haplogroup. The Middle Eastern horses had major genetic contributions to the Western horses and there was no clear pattern of differentiation among all tested populations. Our results also showed that several individuals from different strains shared a single haplotype, and individuals from a single strain were represented in clearly separated haplogroups.ConclusionsThe whole mtDNA D-loop sequence was more powerful for analysis of the maternal genetic diversity in the Arabian horses than using just the HVR1. Native populations from the Middle East, such as Syrians, could be suggested as a hot spot of genetic diversity and may help in understanding the evolution history of the Arabian horse breed. Most importantly, there was no evidence that the Arabian horse breed has clear subdivisions depending on the traditional maternal based strain classification system.
| S-EPMC3847362 | biostudies-literature
Project description:BackgroundEquid herpesvirus 1 (EHV-1) infections are endemic worldwide, including Poland. Many are subclinical, but some are associated with respiratory disease, abortion, neonatal foal death, or neurological disease. We describe an outbreak of abortions in Arabian mares at a well-managed State stud farm in Poland.Case presentationEight of 30 pregnant mares aborted and one gave birth to a weak foal that died within 72 h after birth. EHV-1 was isolated from all fetuses as well as from the diseased foal. All viruses belonged to the N752 variant based on the predicted open reading frame (ORF) 30 amino acid sequence. All were identical to each other and to previous EHV-1 viruses from the same stud based on the ORF68 sequence analysis. The outbreak coincided with the lapse in the routine yearly EHV-1/4 vaccinations of the mares.ConclusionsMultiple abortion due to EHV-1 infection can occur in well-managed groups of horses. Reactivation of latent EHV-1 in one of the resident mares followed by a horizontal spread was considered the most likely explanation for the outbreak. Routine vaccination is an important part of a herd-heath program.
| S-EPMC7539464 | biostudies-literature
Project description:BACKGROUND:Equid herpesviruses (EHVs) are widespread in equine populations worldwide. While the infection with equine ?-herpesviruses (EHV-1 and EHV-4) has been linked to several clinical outcomes, the pathogenic potential for equine ?-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. METHODS:Virus-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. RESULTS:Overall, 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. CONCLUSIONS:The 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 ?-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.
| S-EPMC6042439 | biostudies-literature
Project description:The Arabian horse, one of the world's oldest breeds of any domesticated animal, is characterized by natural beauty, graceful movement, athletic endurance, and, as a result of its development in the arid Middle East, the ability to thrive in a hot, dry environment. Here we studied 378 Arabian horses from 12 countries using equine single nucleotide polymorphism (SNP) arrays and whole-genome re-sequencing to examine hypotheses about genomic diversity, population structure, and the relationship of the Arabian to other horse breeds. We identified a high degree of genetic variation and complex ancestry in Arabian horses from the Middle East region. Also, contrary to popular belief, we could detect no significant genomic contribution of the Arabian breed to the Thoroughbred racehorse, including Y chromosome ancestry. However, we found strong evidence for recent interbreeding of Thoroughbreds with Arabians used for flat-racing competitions. Genetic signatures suggestive of selective sweeps across the Arabian breed contain candidate genes for combating oxidative damage during exercise, and within the "Straight Egyptian" subgroup, for facial morphology. Overall, our data support an origin of the Arabian horse in the Middle East, no evidence for reduced global genetic diversity across the breed, and unique genetic adaptations for both physiology and conformation.
| S-EPMC7298027 | biostudies-literature
Project description:BackgroundArabian horses are believed to be one of the oldest and most influential horse breeds in the world. Blood is the main tissue involved in maintaining body homeostasis, and it is considered a marker of the processes taking place in the other tissues. Thus, the aim of our study was to identify the genetic basis of changes occurring in the blood of Arabian horses subjected to a training regimen and to compare the global gene expression profiles between different training periods (T1: after a slow canter phase that is considered a conditioning phase, T2: after an intense gallop phase, and T3: at the end of the racing season) and between trained and untrained horses (T0). RNA sequencing was performed on 37 samples with a 75-bp single-end run on a HiScanSQ platform (Illumina), and differentially expressed genes (DEGs) were identified based on DESeq2 (v1.11.25) software.ResultsAn increase in the number of DEGs between subsequent training periods was observed, and the highest amount of DEGs (440) was detected between untrained horses (T0) and horses at the end of the racing season (T3). The comparisons of the T2 vs. T3 transcriptomes and the T0 vs. T3 transcriptomes showed a significant gain of up-regulated genes during long-term exercise (up-regulation of 266 and 389 DEGs in the T3 period compared to T2 and T0, respectively). Forty differentially expressed genes were detected between the T1 and T2 periods, and 296 between T2 and T3. Functional annotation showed that the most abundant genes up-regulated in exercise were involved in pathways regulating cell cycle (PI3K-Akt signalling pathway), cell communication (cAMP-dependent pathway), proliferation, differentiation and apoptosis, as well as immunity processes (Jak-STAT signalling pathway).ConclusionsWe investigated whether training causes permanent transcriptome changes in horse blood as a reflection of adaptation to conditioning and the maintenance of fitness to compete in flat races. The present study identified the overrepresented molecular pathways and genes that are essential for maintaining body homeostasis during long-term exercise in Arabian horses. Selected DEGs should be further investigated as markers that are potentially associated with racing performance in Arabian horses.
| S-EPMC5382464 | biostudies-literature