Epidemiology in horses involves the study of the distribution and determinants of health-related states and events in equine populations. It encompasses the investigation of patterns, causes, and effects of diseases and health conditions within horse populations. This field of study aims to identify risk factors for disease and targets for preventive healthcare. Key components of equine epidemiology include disease surveillance, outbreak investigation, and the study of disease dynamics within herds or regions. Research in this area often focuses on infectious diseases, zoonotic diseases, and the impact of environmental factors on equine health. This page compiles peer-reviewed research studies and scholarly articles that explore various aspects of epidemiology in horses, including disease prevalence, transmission pathways, and strategies for disease prevention and control.
Grooters AM, Whittington A, Lopez MK, Boroughs MN, Roy AF.The purpose of this study was to evaluate the effects of sample handling, storage, and culture techniques on the isolation of Pythium insidiosum from infected equine tissues. Tissue and kunker samples obtained immediately posteuthanasia from a horse with subcutaneous pythiosis were used to assess the effects of sample type (kunkers vs. tissues), media type (selective vs. nonselective), storage technique, and storage time on P. insidiosum isolation rate. Overall, isolation rates were higher from fresh kunkers (94.6%) and stored kunkers (76.4%) than from fresh tissues (8.3%) or stored tissues (4...
Christensen H, Bisgaard M, Angen O, Olsen JE.Phenotypic characterization of bacteria from diseased and healthy horses identified 18 isolates as Bisgaard taxon 9 and 11 isolates as Actinobacillus lignieresii. All strains of taxon 9 were alpha-galactosidase- and raffinose-positive and showed variable fermentation of (+)L-arabinose and (-)D-sorbitol. Strains of A. lignieresii were negative for these characteristics, with the exception of raffinose. Two strains from the (-)D-sorbitol-negative group of taxon 9 showed a 16S rRNA similarity of 99-6%, while 99.5% similarity was found between two strains of the (-)D-sorbitol-positive group. DNA-D...
Steinman A, Banet C, Sutton GA, Yadin H, Hadar S, Brill A.Between August and October 2000, 76 horses were reported by veterinary practitioners as having signs of a neurological disorder, varying from an involvement of the spinal cord alone to the entire central nervous system; 15 of the horses died or were euthanased as a result of their grave prognosis or secondary complications. At the same time, an outbreak of West Nile virus infection affected people and birds, principally domestic geese. West Nile virus was isolated from four of the horses with encephalomyelitis and five other horses seroconverted, indicating that the virus was the probable caus...
Engvall EO, Egenvall A.Granulocytic ehrlichiosis is a frequently diagnosed tick-borne disease in Swedish dogs and horses. The infection is caused by a granulocytic Ehrlichia species belonging to the Ehrlichia phagocytophila genogroup. In the acute stage, the disease is mainly characterized as a febrile illness and diagnosis can be confirmed by the demonstration of ehrlichial inclusions in blood granulocytes. Seropositivity in many healthy dogs and horses indicate that the infection also can be transient without clinical signs. The infection can persist in experimentally inoculated animals for months, but to what ext...
Durand B, Chevalier V, Pouillot R, Labie J, Marendat I, Murgue B, Zeller H, Zientara S.During late summer and autumn 2000, a West Nile fever outbreak in southern France resulted in 76 equine clinical cases; 21 horses died. We report the results of a large serosurvey of all equines within a 10-km radius of laboratory-confirmed cases. Blood samples were obtained from 5,107 equines, distributed in groups of 1 to 91 animals. West Nile virus immunoglobulin (Ig) G antibodies were found in 8.5% of animals (n=432). Forty-two percent of the IgG-positive animals were also IgM positive. Horses living in small groups were more affected than those in large groups. The results suggest that We...
Stewart AJ, Hinchcliff KW, Saville WJ, Jose-Cunilleras E, Hardy J, Kohn CW, Reed SM, Kowalski JJ.Medical records of 101 blood culture-confirmed bacteremic foals were reviewed to determine whether foals with Actinobacillus sp. bacteremia are affected at an earlier age, have more severe signs of disease, and have a worse prognosis than do foals with bacteremia of other causes. Thirty percent (30/101) of bacteremic foals had Actinobacillus sp. cultured, and these were 2 times more likely to die (crude odds ratio [OR(CR)] 0.8, 4; P = .14), with a survival rate of 43% (13/30) compared to the overall survival rate of 55% (56/101). When compared to other bacteremic foals, foals with actinobacill...
Müller I, Khanakah G, Kundi M, Stanek G.Grazing animals are continuously exposed to tick bites. Consequently, one may expect that horses will become infected with the various pathogens carried by ticks including Borrelia burgdorferi sensu lato. Whether horses may develop clinical disease due to this pathogen is controversially discussed. We were interested to learn about the infection of horses with Borrelia burgdorferi sensu lato within one season by studying the dynamics of the humoral immune response in paired blood samples. The majority of horses examined were Lipizzaner from the stud farm in Piber/Steiermark, and from the Spani...
Collobert-Laugier C, Hoste H, Sevin C, Chartier C, Dorchies P.From December 1998 to March 2000, caecum and ascendant colon of 42 horses naturally infected with cyathostomes were collected during routine necropsy or from a local slaughterhouse. Changes in the numbers of mucosal and submucosal mast cells (MMC and SMMC), intraepithelial, mucosal and submucosal eosinophils (IE, ME and SME) in the large intestine were investigated by histochemical techniques in relation to the worm burdens. The effect of age was examined in three subgroups: 6-24-month-old horses (group 1), 2-10-year-old horses (group 2) and horses more than 10 years of age (group 3). No globu...
Foote CE, Love DN, Gilkerson JR, Whalley JM.Equine herpesvirus 1 (EHV-1) is a major cause of respiratory disease and abortion in horses worldwide. Although some vaccines have been shown experimentally to reduce disease, there are few reports of the responses to vaccination in the field. This study measured antibody responses to vaccination of 159 mares (aged 4-17 years) and 101 foals (aged 3-6 months) on a large stud farm with a killed whole virus EHV-1/4 vaccine used as per the manufacturer's recommendations. Using an EHV glycoprotein D (gD)-specific ELISA and a type-specific glycoprotein G (gG) ELISA, respectively 13.8 and 28.9% of ma...
Adam EN, Morley PS, Chmielewski KE, Carman J, Gonzales G.Because of the contagious nature of influenza virus it is necessary to identify infected individuals after the virus is introduced into a population. The aim of this study was to characterise influenza virus detection with commercially available assays after intranasal vaccinating horses with cold-adapted influenza virus. Seven horses were vaccinated and placed with 3 unvaccinated horses. Nasal secretion samples were evaluated using 2 antigen detection assays. All 10 horses were positive in the Flu OIA assay during the study period, but only one horse was positive on one sample using the Direc...
Kolm-Stark G, Wagner R.Icelandic horses in Austria are commonly affected by an allergic inflammatory skin disease recurring during the summer seasons, which shares characteristic features with Culicoides hypersensitivity. However, the causative agents have not yet been identified. Therefore, intradermal skin testing (IDST) with a standardised extract of Culicoides variipennis and 21 other allergens relevant within Austria was performed in 81 Icelandic horses. All horses included into the study were treated regularly with ivermectin and had no history of administration of anti-inflammatory drugs. Forty-three of these...
Glass K, Wood JL, Mumford JA, Jesset D, Grenfell BT.This paper demonstrates that a simple stochastic model can capture the features of an epidemic of equine influenza in unvaccinated horses. When the model is modified to consider vaccinated horses, we find that vaccination dramatically reduces the incidence and size of epidemics. Although occasional larger outbreaks can still occur, these are exceptional. We then look at the effects of vaccination on a yard of horses, and in particular at the relationship between pre-challenge antibody level and quantity of virus shed when challenged with the virus. While on average, a high antibody level impli...
van Maanen C.Equine herpesvirus 1 (EHV1) and equine herpesvirus 4 (EHV4) are important ubiquitous equine viral pathogens, causing much damage to the horse industry. EHV1 strains are associated with respiratory disease, abortion, and paresis/paralysis, whereas EHV4 strains are predominantly associated with respiratory disease. In the past decades much research effort has been put into improving knowledge about these viruses. In this paper the current state of knowledge of these viruses and the most important aspects of these virus infections, e.g. epidemiology, clinical aspects, pathogenesis and pathology, ...
van Maanen C, Cullinane A.Equine influenza is one of the most economically important contagious respiratory diseases of horses. In this paper the current state of knowledge of equine influenza virus and the most important aspects of these virus infections, e.g. epidemiology, clinical aspects, pathogenesis and pathology, immunity, diagnosis, treatment, management and vaccination, are reviewed with an emphasis on epidemiology, diagnosis and vaccinology. Many questions have remained and with the advent of improved technology new questions have arisen. Consequently, research priorities should be set in an attempt to answer...
Howell PG, Groenewald D, Visage CW, Bosman AM, Coetzer JA, Guthrie AJ.Selected isolates of equine encephalosis virus were shown to have comparable viral protein profiles and to represent seven distinct serotypes, based on cross-neutralization tests. Serotype-specific virus-neutralizing antibody in serum samples from horses confirmed the widespread occurrence of infection. The distribution and prevalence of individual serotypes however, varied considerably. Localised foci with an increased seasonal seroconversion in groups of horses to a specific serotype and the detection of an ongoing low level of infection from other serotypes within the population, confirmed ...
Derlet RW, Carlson JR.To determine the prevalence of microorganisms that are potentially pathogenic for humans in horse/mule manure along the John Muir Trail (JMT). Methods: Random samples of horse/mule manure were collected along sections of the JMT in Yosemite, Kings Canyon, and Sequoia national parks (NP), as well as in portions of the Pacific Crest Trail (PCT) and selected JMT/PCT access trails. Convenience samples of wild animal scat found within I mile of trails were also collected. The fresh specimens were individually preserved both in 0.9% saline and polyvinyl alcohol (PVA)-containing tubes and stored at 4...
Morehead JP, Blanchard TL, Thompson JA, Brinsko SP.To determine features of an early fetal loss (EFL) syndrome and evaluate potential risk factors for EFL in Thoroughbred broodmares on 4 farms in central Kentucky. Methods: Retrospective study. Methods: 288 pregnant broodmares. Methods: Year-2001 breeding records for 288 Thoroughbred broodmares were examined. Early fetal loss was defined as loss of a fetus that was viable at > or = 40 days of gestation but was subsequently lost by 5 months of gestation. Results: Overall 2001 EFL rate was 25% (73/288), median gestational age at time of fetal loss was 77 days, and median date of loss was May 7...
Palacios H, Hibarren I, Olalla MJ, Cala V.The diagnosis of lead poisoning in horses living on farmland in the vicinity of a battery recycling plant was based on clinical signs as well as on laboratory findings. Chemical analysis of six surface soils (0-15 cm) and herbage samples taken at different distances to the recycling plant showed very high total lead levels in the closest sites to the facility and a clear decrease with distance. Total lead levels in soil samples ranged from 127 to 5657 mg kg(-1), with more than 70% of lead extractable by EDTA in the most polluted soils. Lead levels in the aerial part of herbage samples were in ...
Malkinson M, Banet C.Surveys on wild birds conducted during the last two decades in Europe, notably Poland and the Czech Republic, to determine their infection rate with WN virus have revealed endemic foci of infection. Some species of seropositive birds were nonmigrators while others were hatchlings of migrating species. Persistently infected avian reservoirs are potential sources of viruses for mosquitoes that multiply in the temperate European zone in hot, wet summers. In the past, evidence for geographical circulation of WN viruses was based on antigenic analysis of strains from different countries while more ...
McLean RG, Ubico SR, Bourne D, Komar N.WN virus is one of the most ubiquitous arboviruses occurring over a broad geographical range and in a wide diversity of vertebrate host and vector species. The virus appears to be maintained in endemic foci on the African continent and is transported annually to temperate climates to the north in Europe and to the south in South Africa. Reports of clinical disease due to natural WN virus infection in wild or domestic animals were much less common than reports of infection (virus isolation or antibody detection). Until recently, records of morbidity and mortality in wild birds were confined to ...
Garrett LA, Brown R, Poxton IR.This study compares quantitatively the microbiota of the gastrointestinal tract of healthy horses with that of horses with equine grass sickness (EGS). Faecal and ileal samples were cultured quantitatively on selective and non-selective media. Confirmed anaerobes were identified to species level. Overall faecal counts gave a ratio of aerobes:anaerobes of approximately 1:1. However, the mean counts in healthy horses of 4.4x10(8) aerobes:3.7x10(8) anaerobes per gram wet weight were different from counts in EGS (means were 10-100-fold higher), with statistically significant differences for the an...
In 2001, West Nile virus (WNV) activity was reported from 359 counties in 27 states and the District of Columbia (DC) to ArboNET, a web-based, surveillance data network maintained by 54 state and local public health agencies and CDC. This activity represented a marked increase from 2000, when WNV activity was reported from 138 counties in 12 states and DC. This report summarizes surveillance data for 2001, which indicate that 66 human illnesses were reported from 10 states and that widespread WNV activity in birds, horses, and mosquitoes extended into the midwestern United States and several s...
Hasegawa M, Amano A, Muraoka H, Kobayashi I, Kimoto M, Kato M, Fujioka T, Nasu M.We conducted a study for the growth of and selectivity for the desired microorganisms using a newly developed selective culture medium for Helicobacter pylori, Columbia horse blood agar HP (CHBHP), at three different Japanese clinical laboratories, Hokkaido, Kanto and Kyusyu. When standard strains and clinical isolates of H. pylori were examined, the recovery of the organism on the CHBHP media was comparable to that of conventional selective and nonselective media. However, colonies were obviously larger on the CHBHP media. These media yielded the highest H. pylori positive rate for clinical s...
Inoue Y, Yamaguchi K, Sawada T, Rivero JC, Horii Y.Borna disease virus (BDV)-specific antibodies were monitored in Misaki feral horses annually for 4 years using an electrochemiluminescence immunoassay (ECLIA). Among 130 horses examined, 35 (26.9%) with an ECLIA count above 1000 once or more were judged as BDV seropositive. Throughout the study period, p24 antibodies were more frequent than p40 antibodies in almost all positive animals. Among the 35 seropositive horses, the ECLIA count was consistently high in 12 cases. Eleven horses seroconverted from negative to positive and 7 underwent reversal. The count in the remaining 95 horses (73.1%) ...
Gupta GD, Lakritz J, Kim JH, Kim DY, Kim JK, Marsh AE.Parasite-specific antibody responses to Neospora spp. and Toxoplasma gondii, antigens were detected using the indirect fluorescent antibody test (IFAT) and immunoblot analysis in a korean equine population located on Jeju island, South Korea (126 degrees 12' E and 33 degrees 34' N). For comparison, a naturally infected Neospora hughesi horse and an experimentally inoculated T. gondii equid (pony) were used. In addition, all samples were tested for antibodies to Sarcocystis neurona by immunoblot analysis. A total of 191 serum samples from clinically normal horses were evaluated. Only 2% (4 out ...
Dowdall SM, Matthews JB, Mair T, Murphy D, Love S, Proudman CJ.Equine clinical larval cyathostominosis is caused by simultaneous mass emergence of previously inhibited larvae from the mucosa of the colon. Clinical signs include diarrhoea, colic, weight loss and malaise, and in up to 50% of cases, the disease results in death. Cyathostominae spend a large part of their life cycle as larval stages in the intestinal mucosa. Definitive diagnosis is difficult due to the lack of diagnostic methods for pre-patent infection. In the present study, the enzyme-linked immunosorbent assay (ELISA) was used to investigate isotype responses to larval cyathostominae somat...
Nordengrahn A, Merza M, Ros C, Lindholmc A, Palfl V, Hannant D, Belák S.Equineherpesvirustypes 2 and 5 (EHV-2andEHV-5)have a rather unclearpathogenicity and distribution within the equid population. In order to gain more information on the prevalence of these two viruses, type-specific PCR assays were developed to detect viral DNA in nasal specimens and in peripheral blood leukocytes (PBLs) of adult horses and foals from various regions of Europe, i.e. Sweden, Hungary and the United Kingdom. In adult horses, the prevalence of EHV-2 in PBLs was up to 68% in Sweden and 71% in the United Kingdom. EHV-2 DNA was detected in the PBLs from all the foals tested in all cou...
Jakob HP, Eckert J, Jemmi T, Gottstein B.For many decades trichinellosis has not been reported among Swiss domestic pigs. Considering the fact that Trichinella occurs in a sylvatic cycle in Switzerland, a study was designed to reevaluate the present epidemiologic situation by investigating 10,904 fattening pigs, 218 pigs with free access to pasturage or being kept on an alp, 104 domestic boars, 106 horses, 44 wild boars and 538 foxes using a direct and an indirect diagnostic technique (digestion method and serology with ELISA and an excretory/secretory antigen, respectively). The digestion method was performed according to EC-guideli...
Edwards SE, Martz KE, Rogge A, Heinrich M.Equine dysautonomia or equine grass sickness (EGS), as it is more commonly known, is a usually fatal disease of equids of uncertain etiology, although associated with grazing, that affects the autonomic and enteric nervous system. Lowered gastrointestinal motility, leading to paralysis of the gut, is one of the main symptoms of EGS. Previous studies have implicated anaerobic bacteria, notably Clostridium botulinum, but what triggers the severe bacterial infestations remains enigmatic. We hypothesized that a detailed comparison of soil mineral and botanical composition of EGS and control sites ...
Aribam SD, Ogawa Y, Matsui H, Hirota J, Okamura M, Akiba M, Shimoji Y, Eguchi M.Serotyping is an important element for surveillance of Salmonella. In this study, an anti-O:4 Salmonella monoclonal antibody-based competitive enzyme-linked immunosorbent assay that could identify Salmonella infection in cow, pig, horse, and chicken was developed. This detection system can therefore be useful for a wide range of animals and for humans.
Kölbl S, Schuller W, Pabst J.944 serum samples of horses, collected in 1988 and 1989, were examined for the occurrence of antibodies against equine arteritis virus by a microneutralizations test. In 10.9% of all sera reactors could be found. The distribution of seropositive horses varied from 4.6% (Salzburg) to 15.7% (Lower Austria). From Tyrol and Vorarlberg no samples could be obtained. It was not possible, to correlate clinical symptoms (infertility, respiratory symptoms, fever and edema) with the infection. It is assumed, that the disease appears in Austria only in a clinical inapparent form.
Stratton LG, Corstvet R, Brown J, Corley L.K. pneumoniae capsule type 68 infused into the uterus of 4 mares was recovered up to 15 weeks after inoculation. The insertion of a tampon for 10 min was more effective than a swab technique in detecting the organism in the uterus. The clitoral fossa and the urethral orifice when sampled by the swab technique were also found to be infected for a comparable period. K. pneumoniae was isolated from the clitoral specimens more often and more consistently than from either urethral or uterine specimens.
Petrov AA, Lebedev VN, Kulish VS, Pyshnaya NS, Stovba LF, Borisevich SV.Epidemiologic analysis of epidemic outbreaks caused by American equine encephalitis causative agents is carried out in the review. Eastern equine encephalomyelitis (EEE), Western equine encephalomyelitis (WEE) and Venezuela equine encephalomyelitis (VEE) viruses are etiologic agents of dangerous transmissive diseases that are usually accompanied by fever and neurologic symptoms. Among the New World alphaviruses, VEE virus has the most potential danger for humans and domestic animals. Currently, enzootic strains of VEE play an increasing role as etiologic agents of human diseases. Most of the V...
Carman MG, Hodges RT.Nineteen isolates of Actinobacillus suis were recovered from horses during the period October 1978-December 1980. Animals varied in age from a full term foetus to 12 years. One isolate was obtained from the nose of an apparently healthy horse, the remainder were obtained from still-born foetuses (2), foals dying within a week of birth (5), older animals with respiratory (6) or genital infections (3) or abscesses in the jaw (1). One isolate was obtained from the lung of a 2-week-old foal which had shown diarrhoea. The bacteriological characteristics of the isolates and the pathological lesions ...
Gitari A, Nguhiu J, Varma V, Mogoa E.The aim of this study was to determine the treatments and their outcomes in horses with colic in Nairobi County, Kenya. Methods: This is a retrospective study to determine the occurrence, treatments, pain management, and outcomes of colic in horses in Nairobi County. Association between pain management protocols and the outcomes of colic with regard to recovery or death was also determined. Data collected from four equine practitioners were organized manually and given numerical codes as appropriate to facilitate entry into the computer. The coded data were entered into Microsoft Excel 2010 an...
Schvartz G, Epp T, Burgess HJ, Chilton NB, Armstrong JS, Lohmann KL.Passive surveillance of ticks on horses in Saskatchewan revealed that the horses were parasitized by 3 species, Dermacentor albipictus, D. andersoni, and D. variabilis. The nymphs and adults of D. albipictus occurred on horses earlier in the year than did adults of the 2 other species. Une surveillance passive des tiques chez des chevaux de la Saskatchewan a révélé que les chevaux étaient affectés par des parasites de trois espèces: et Les nymphes et les adultes de se présentaient chez les chevaux plus tôt dans l’année que les adultes des deux autres espèces.(Traduit par Isabel...
Cabral LDR, Sato AP, de Sousa RS, Rossa AP, Sanches AWD, Bortoleto CT, Locatelli Dittrich R.The closely related apicomplexa protozoa, Toxoplasma gondii, Neospora spp., and Sarcocystis neurona, have all been associated with neurological and reproductive diseases in horses. However, there is limited data regarding the presence of these three parasites in equine placental tissues and amniotic fluid. The aim of the present report was to investigate the presence of the DNA of T. gondii, Neospora spp. and S. neurona in placentas and amniotic fluid in mares. Anti-T. gondii, anti- S. neurona and anti- Neospora spp. antibody titers were evaluated in 31 mares in the final third of pregnancy by...
Raftery AG, Jallow S, Coultous RM, Rodgers J, Sutton DGM.Equine trypanosomiasis is a severe and prevalent disease that has the greatest impact globally upon working equids due to its distribution across lower income countries. Morbidity and mortality rates are high; disease management strategies in endemic regions are ineffective and cost prohibitive. Individual variation in disease phenotype in other species suggests host factors could reveal novel treatment and control targets but has not been investigated in equids. Methods: A prospective clinical evaluation of equines presenting for a free veterinary examination was performed in hyperendemic vil...
Copetti MV, Santurio JM, Boeck AA, Silva RB, Bergermaier LA, Lubeck I, Leal AB, Leal AT, Alves SH, Ferreiro L.This article reports an outbreak of intoxication of female horses with Claviceps purpurea in southern Brazil. The outbreak affected twelve pregnant mares which were fed with black oat (Avena strigosa) during the pre-delivery period. Underdevelopment of the mammary gland in the pre-delivery period resulting in post-delivery agalactia was the most pronounced finding. These mares delivered weak and unviable foals, which showed no suckling reflex and died within a few hours of birth. Laboratory analysis of oat samples fed to the animals resulted in the identification of Claviceps purpurea scleroti...
Nollet H, Vercauteren G, Martens A, Vanschandevijl K, Schauvliege S, Gasthuys F, Ducatelle R, Deprez P.In Belgium and even in northern Europe Rhinosporidium seeberi has not been reported in autochtonous people or animals. In this paper, the authors report the first observation of laryngeal masses, caused by Rhinosporidium seeberi, in a Belgian Warmblood horse. Moreover, laryngeal rhinosporidiosis is extremely rare since this localisation is only described in four human cases.
Brethes B, Puech PL, Fraisse A, Dubois P, Domenech J, Bourdin P, Moreau JP, Capdevielle P, Desoutter D, Lechapt M.This epidemiological survey includes the study of human and animal leptospirosis in New Caledonia from clinical cases as well as a systematic serological study about exposed human and animal populations. The results show that this disease is endemic on the whole territory with a few important focuses in agricultural area, especially on the Western coast. Leptospira icterohemorrhagiae is the main serotype and is responsible for serious human leptospirosis. The male farmers constitute the most exposed population, especially from March to May, end of the host season. In order to reduce the import...
Nelson DM, Gardner IA, Chiles RF, Balasuriya UB, Eldridge BF, Scott TW, Reisen WK, Maclachlan NJ.Jamestown Canyon (JC) and Saint Louis encephalitis (SLE) viruses are mosquito-transmitted viruses that have long been present in California. The objective of this study was to determine the seroprevalence of these two viruses in horses prior to the introduction of West Nile (WN) virus. Approximately 15% of serum samples collected in 1998 from 425 horses on 44 equine operations horses throughout California had serum antibodies to JC virus, whereas antibodies were not detected to SLE virus. The results indicate that horses in California were commonly infected prior to 1998 with mosquito-transmit...
Dong J, Cook FR, Haga T, Horii Y, Norimine J, Misawa N, Goto Y, Zhu W.Although equine infectious anemia virus (EIAV) poses a major threat to the equine industry worldwide, the molecular epidemiology of this virus is poorly understood. Recently, an EIAV strain (EIAVMiyazaki2011-A) representing a new monophyletic group was discovered in feral horses in southern Japan. In the present study, the EIAVMiyazaki2011-A proviral genome is compared with evolutionarily divergent EIAV isolates to investigate conservation of functional elements or motifs within the long terminal repeats (LTRs) and structural genes. This analysis represents a significant step forward in increa...