Investigation of Cerebellar Abiotrophy (CA), Lavender Foal Syndrome (LFS), and Severe Combined Immunodeficiency (SCID) Variants in a Cohort of Three MENA Region Horse Breeds

Genetic disorders in horses are mostly fatal or usually cause significant economic losses for breeders and owners. Here we studied a total of 177 Arabian, Barb and Arab-Barb horses from the Middle East and North Africa (MENA) using Sanger Sequencing and PCR-ACRS (polymerase chain reaction—artificially created restriction site) approaches to examine the genetic disorders in the studied horse breeds. We identified the genetic variations related to Cerebellar Abiotrophy (CA), Severe Combined Immunodeficiency (SCID) occurrence, and the studied population was free of the mutant allele determined Lavender Foal Syndrome (LFS). Overall, presented data showed that 15 of the studied horses are carriers of two genetic disorders; the investigated horse population showed that five Arabian horses were heterozygous for the CA-associated SNP (rs397160943). The SCID-deletion TCTCA within PRKDC was detected in ten horses (nine Arabian horses and one Arab-Barb horse). This investigation shows the importance of testing these breeds for genetic disorders to avoid further spread of deleterious variants

Equine vitiligo-like depigmentation in grey horses is related to genes involved in immune response and tumor metastasis

Background In horses, the autoimmune disease vitiligo is characterized by the loss of melanocytes and results in patchy depigmentation of the skin around the eyes, muzzle and the perianal region. Vitiligo-like depigmentation occurs predominantly in horses displaying the grey coat colour and is observed at a prevalence level of 26.0–67.0% in grey horses compared with only 0.8–3.5% in non-grey horses. While the polygenetic background of this complex disease is well documented in humans, the underlying candidate genes for this skin disorder in horses remain unknown. In this study we aim to perform a genome-wide association study (GWAS) for identifying putative candidate loci for vitiligo-like depigmentation in horses. Methods In the current study, we performed a GWAS analysis using high-density 670 k single nucleotide polymorphism (SNP) data from 152 Lipizzan and 104 Noriker horses, which were phenotyped for vitiligo-like depigmentation by visual inspection. After quality control 376,219 SNPs remained for analyses, the genome-wide Bonferroni corrected significance level was p < 1.33e-7. Results We identified seven candidate genes on four chromosomes (ECA1, ECA13, ECA17, ECA20) putatively involved in vitiligo pathogenesis in grey horses. The highlighted genes PHF11, SETDB2, CARHSP1 and LITAFD, are associated with the innate immune system, while the genes RCBTB1, LITAFD, NUBPL, PTP4A1, play a role in tumor suppression and metastasis. The antagonistic pathogenesis of vitiligo in relation to cancer specific enhanced cell motility and/or metastasis on typical melanoma predilection sites underlines a plausible involvement of RCBTB1, LITAFD, NUBPL, and PTP4A1. Conclusions The proposed candidate genes for equine vitiligo-like depigmentation, indicate an antagonistic relation between vitiligo and tumor metastasis in a horse population with higher incidence of melanoma. Further replication and expression studies should lead to a better understanding of this skin disorder in horses.

Genetic Characterization of Equine Herpesvirus 1 from Clinical Cases and Asymptomatic Horses in Serbia and Bosnia and Herzegovina

Equine herpesvirus 1 (EHV-1) causes considerable economic loss to the equine industry and is spread among susceptible animals during the cycles of latency and reactivation, causing rhinopneumonitis, abortion, and neurological disease. Nucleotide polymorphisms within ORF30 and ORF68 sequences of the viral genome are associated with strain neuropathogenicity and geographical origin. A total of 142 tissue and nasal swab samples from apparently healthy unvaccinated horses were examined to ascertain EHV-1 distribution, diversity, and clinical significance considering the results of virus isolation, sequence analysis, and anamnestic data. The ORF30 and ORF68 molecular study of these circulating strains and archival isolates from abortion storms aimed to contribute to the perception of strain pathogenicity and origin. EHV-1 was detected by PCR and virus isolation in 81 and 45.1% of the analyzed samples, respectively, and 82.1% of the representative samples were neuropathogenic strains. The ORF68-based grouping was restricted by the pronounced polymorphism of Balkan EHV-1 strains, and only two isolates were assigned to group 4. The cases of abortion were caused by neuropathogenic strains that also circulate within the horse population with no documented outbreaks of disease. It was evident that strain virulence is not solely accountable for the development of clinical symptoms in affected animals. Neural tissue is significant for virus latency and reactivation, considering the number of EHV-1 isolates from apparently healthy stressed horses. Special care must be taken when accommodating together immunologically naive and latently infected horses since asymptomatic carriers silently shed EHV-1.

Efficacy of Albendazole Against Strongylus sp. and Hematology Changes on Equine in Yogyakarta Special Region

The infestation of Strongylus sp. in horses can cause losses to horse breeders, including anorexia, anemia, gastrointestinal diseases and can cause death and decrease the horse population in DIY. Albendazole was a Benzimidazole preparation that is often used to treat worms in ruminants. This study also aims to determine the effect of Albendazole on blood images before and after treatment. The material used in this study were 10 horses with male and female sex, over 3 years old, and infected with Strongylus sp. with an infestation rate of 200 EPG in faeces. Before treatment of drug was carried out, the faeces was examined with Mc Master method. After treatment with Albendazole, the worm eggs were examined three times at intervals of three days. Routine examination of worm eggs and blood was carried out at the Laboratory of the Department of Internal Medicine, Faculty of Veterinary Medicine, Universitas Gadjah Mada. The results showed that the EPG number decreased from the 0th, 3rd, 6th and 9th day of examinations. The average number of EPG on the 0th day was 990 eggs/gram, and the examination on the 9th day showed the number of eggs was 0 eggs/gram. The results of the hematology examination also showed no significant difference except for the high number of eosinophils on the 12th day after drug administration. The conclusion from this research is that Albendazole as a worm medicine can kill Srongylus sp. however, it does not affect the horse's hematology and health status.

Middle Pleistocene Variations in the Diet of Equus in the South of France and Its Morphometric Adaptations to Local Environments

Equus is a very sensitive genus which has expanded over a large area and lived in Europe despite the climatic instability of the Pleistocene. Its persistence and abundance are helpful in understanding and describing environmental and climatic regional parameters. In this study, we present the result of dental mesowear and microwear analysis and post-cranial skeleton biometry on Equus populations located in two regions in the South of France from ten sites, corresponding to twelve assemblages dated from MIS 12 to MIS 5. The areas refer to two major climatic zones: the oceanic or subcontinental climate for the South West of France, and the Mediterranean for the South East. The first objective of this study is to integrate and compare biometric data, dental wear, and other already-published environmental proxies. The goal is to discuss the validity of horse body shape adaptations on a small geographical scale. The second objective is to describe the impact of environmental features on the horse population through time in the two regions. We observe that the Equus diet was quite diverse, according to microwear analysis which shows adaptations according to seasonal variations. However, they remained mostly grazers over a long period of time. Estimated body mass of Equus in the localities studied here varies from a mean of 468 up to a mean of 570 kg, but these variations failed to be correlated with the diet, the climatic period, or the geographical position of the horse population, probably because of the sample size or the restricted time-span or geographical scale. However, the conformation of the metapodials and the width of the third phalanges may have been linked with environmental and behavioural parameters. The width of the third phalange may be correlated with the recurrence of the snow cover, while the robustness of the metapodial co-occurs with a humid climate. Also, diet may influence the conformation of the bones, since the tall and slender horses seem to be preferentially grazers all year long and seasonally browser horses are tall and robust. Seasonally mixed-feeder horses, all coming from the Mediterranean area, were found to be smaller, perhaps in relation to a less productive environment. The correspondence of the dietary and morphometrical data could suggest high pressure on the horse population, which caused rapid body adaptation. Thus, the combination of these different proxies allows us to suggest more accurate large mammal paleoenvironmental reconstructions.

Serological Survey of Leptospira Infection in Arabian Horses in Poland

Leptospirosis is one of the most common zoonotic infections worldwide, including in most livestock, some companion animals, horses, wildlife, and humans. Epidemiological estimation of its prevalence in all species is difficult due to the variety of clinical presentations and challenges regarding laboratory diagnosis. The purpose of this study was to measure the seroprevalence of leptospiral infection in Arabian horses kept in the largest breeding farms in Poland, representing over 15% of the Polish Arabian horse population. Leptospira antibodies were detected by MAT (cut-off 1:100) in 33.2% of serum samples (204 of 615 animals) (CI 95%: 29.6–37.0%), most frequently reacting with the serovar Grippotyphosa, similar to previous reports in populations of randomly selected horses. These results indicated high Leptospira seropositivity, thus, although any form of clinical leptospirosis is rare, it may be postulated that the leptospiral exposure is widespread.

Evaluation of genetic diversity of subdivided genealogical groups in Lithuanian Trakehner horse population using immunogenetic tools

The objective of this study was to evaluate the inter-breed genetic diversity of Lithuanian Trakehner horses. The current population in Lithuania numbers 1 039 Trakehner horses. The study included the immunogenetic data analysis of 316 blood samples. Pedigree was traced back to 7–11 generations. The horses were assigned to genealogical clusters originating from East Prussian Trakehnen Stud, Thoroughbred and Arab sires. The first two clusters were subdivided into nine-horse groups according to the most important ancestors. The evaluation of genetic diversity was based on six blood groups and five protein polymorphism systems. The differences between genealogical groups were confirmed by principal component analysis and applied cluster analysis. According to the allelic frequency, the Trakehner population changed very slightly through a 30-year period, and only one rare (0.013) allele Tf^RR (frequent in other Trakehner populations), has been newly found. The analysis of genetic polymorphism systems based on a very low rate of alleles Q^abc (0.093) and D^dkl (0.046), which are typical of other populations, indicated the exclusivity of the Trakehner population in Lithuania. The average expected heterozygosity by blood protein polymorphism and blood groups were 0.409 and 0.441, respectively. The genetic clustering diverged by observed heterozygosity of blood groups and by pedigree data in Pilger through Egoist, Bay Ronald through Dark Ronald and Dampfross through Hyperion subgroups. The determined distinctiveness of subdivided Trakehner horse groups suggests reconsidering the breeding strategies and conservation programme of Trakehner horses. Breeding and selection of subdivided sire lines could be among the appropriate solutions for the maintenance and extension of the genealogical structure.