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Veterinary research communications2026; 50(4); 310; doi: 10.1007/s11259-026-11261-w

First confirmed report of equine coital exanthema in Uruguayan horses.

Abstract: Equine Coital Exanthema (ECE) is a contagious venereal disease caused by Equid alphaherpesvirus 3 (EHV‑3). Although ECE is self-limiting, it causes significant economic losses to the global equine industry due to the temporary segregation of affected mares and stallions from breeding activities. This report describes the epidemiological, clinical, histological, and molecular findings from an outbreak of ECE in Uruguayan horses. Seven days following the introduction of a stallion, five mares developed extensive papular and vesicular dermatitis in the vaginal and perineal regions. The stallion exhibited minimal preputial mucosal ulcerative lesions. Histological examination of skin biopsies from three affected mares revealed ulcerative dermatitis with intranuclear eosinophilic inclusion bodies in keratinocytes. Molecular confirmation of EHV‑3 infection was achieved by qPCR analysis of perineal skin samples from a mare with typical ECE lesions.
© 2026. The Author(s), under exclusive licence to Springer Nature B.V.
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Publication Date: 2026-05-09 PubMed ID: 42105035PubMed Central: 12146816DOI: 10.1007/s11259-026-11261-wGoogle Scholar: Lookup
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Summary

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Equine Coital Exanthema (ECE), a contagious venereal disease caused by Equid alphaherpesvirus 3 (EHV-3), was reported for the first time in Uruguayan horses, with affected animals showing characteristic skin lesions and confirmed viral infection.

Introduction to Equine Coital Exanthema (ECE) and Significance of the Study

  • ECE is a venereal disease affecting horses, caused by the Equid alphaherpesvirus 3 (EHV-3).
  • Though the disease is self-limiting, it has serious economic implications due to the need to isolate affected animals to prevent spread.
  • The disease mainly affects breeding animals, leading to temporary cessation of breeding activities.
  • This report provides the first confirmed outbreak of ECE in horses in Uruguay, contributing to the epidemiological knowledge of the disease in South America.

Outbreak Description and Clinical Presentation

  • The outbreak began seven days after the introduction of a stallion to a group of mares.
  • Five mares developed noticeable skin lesions, specifically extensive papular (raised) and vesicular (blister-like) dermatitis located in the vaginal and perineal regions.
  • The stallion presented only mild ulcerative lesions on preputial mucosa, indicating less severe visible symptoms.

Histological Findings

  • Skin biopsies were taken from three affected mares for microscopic examination.
  • These biopsies revealed ulcerative dermatitis characterized by tissue breakdown in the skin.
  • Importantly, intranuclear eosinophilic inclusion bodies were found within keratinocytes—these are characteristic microscopic features indicating herpesvirus infection.
  • Such histological markers help in differentiating ECE from other dermatological conditions in horses.

Molecular Diagnosis

  • Confirmation of EHV-3 as the causative agent was performed using quantitative Polymerase Chain Reaction (qPCR), a sensitive molecular technique for viral DNA detection.
  • Samples for qPCR analysis were taken from perineal skin lesions of a mare exhibiting typical clinical signs of ECE.
  • This molecular approach definitively confirmed the presence of EHV-3, ruling out other potential pathogens.

Implications and Conclusions

  • The study documents the introduction and spread of ECE in Uruguay, showing the disease’s potential to spread quickly after the introduction of an infected stallion.
  • It highlights the need for careful screening and management of breeding animals to prevent outbreaks.
  • The findings support the use of combined clinical, histological, and molecular methods for accurate diagnosis of ECE.
  • Understanding local outbreaks helps inform biosecurity measures and economic decisions in the equine breeding industry.

Cite This Article

APA
Machado M, Alves M, Coubrough C, Queiroz-Machado CRR, Barrandeguy M, Vissani A, Carossino M, Menchaca A. (2026). First confirmed report of equine coital exanthema in Uruguayan horses. Vet Res Commun, 50(4), 310. https://doi.org/10.1007/s11259-026-11261-w

Publication

Veterinary research communications
ISSN: 1573-7446
NlmUniqueID: 8100520
Country: Switzerland
Language: English
Volume: 50
Issue: 4
PII: 310

Researcher Affiliations

Machado, Mizael
  • Plataforma de Investigación en Salud Animal (PSA), Instituto Nacional de Investigación Agropecuaria (INIA), Tacuarembó, Uruguay. mmachado@inia.org.uy.
Alves, Martín
  • Veterinary consultant, Tacuarembó, Uruguay.
Coubrough, Charles
  • Veterinary consultant, Montevideo, Uruguay.
Queiroz-Machado, Cintia R R
  • Centro Universitario Regional (CENUR) Noreste, Universidad de la República (Udelar), Tacuarembó, Uruguay.
Barrandeguy, María
  • Plataforma de Investigación en Salud Animal (PSA), Instituto Nacional de Investigación Agropecuaria (INIA), Colonia, Uruguay.
Vissani, Aldana
  • Instituto de Virología, CICVyA, Instituto Nacional de Tecnología Agropecuaria (INTA), Buenos Aires, Argentina.
Carossino, Mariano
  • Department of Pathobiological Sciences & Louisiana Animal Disease Diagnostic Laboratory, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
Menchaca, Alejo
  • Plataforma de Investigación en Salud Animal (PSA), Instituto Nacional de Investigación Agropecuaria (INIA), Tacuarembó, Uruguay.
  • Plataforma de Investigación en Salud Animal (PSA), Instituto Nacional de Investigación Agropecuaria (INIA), Colonia, Uruguay.

MeSH Terms

  • Animals
  • Horses
  • Horse Diseases / virology
  • Horse Diseases / epidemiology
  • Horse Diseases / pathology
  • Female
  • Exanthema / veterinary
  • Exanthema / virology
  • Exanthema / epidemiology
  • Exanthema / pathology
  • Herpesviridae Infections / veterinary
  • Herpesviridae Infections / epidemiology
  • Herpesviridae Infections / virology
  • Herpesviridae Infections / pathology
  • Herpesvirus 3, Equid / isolation & purification
  • Uruguay / epidemiology
  • Disease Outbreaks / veterinary

Conflict of Interest Statement

Declarations. Ethics approval: The authors stated that the animal treatment and clinical examinations were conducted in accordance with national legal and ethical requirements under Uruguayan law. The outbreak occurred spontaneously and no experiments were performed. Competing interests: The authors declare no competing interests.

References

This article includes 18 references
  1. Ataseven VS, Dogan F, Bilge dagalp S, Tan MT, Altinbay K, Ates CT. Serological survey of equid herpesvirus 3 infection in Turkish horses. Turk J Vet Anim Sci 38:295–298.
    doi: 10.3906/vet-1311-72google scholar: lookup
  2. Atay YE, Ekinci G, Öztürk AE, Timur MC, Mete A, Altınbay K, Derelli FM, Akar Y, Keleş İ. Clinical Prevalence of Equine Coital Exanthema in a Thoroughbred Covering Station in Türkiye (2021–2024). Reprod Domest Anim 60(6):e70086.
    doi: 10.1111/rda.70086pubmed: 40485269pmc: 12146816google scholar: lookup
  3. Barrandeguy M, Perkins J, MacDonough J, Vissani A, Olguin Perglione C, Thiry E. Occurrence of equine coital exanthema in mares from an embryo transfer center. J Equine Vet Sci 30:145–149.
    doi: 10.1016/j.jevs.2010.01.059google scholar: lookup
  4. Barrandeguy M, Thiry E. Equine coital exanthema and its potential economic implications for the equine industry. Vet J 191(1):35–40.
    doi: 10.1016/j.tvjl.2011.01.016pubmed: 21354835google scholar: lookup
  5. Barrandeguy M, Ulloa N, Bok K, Fernandez F. Outbreak of rhinitis caused by equid herpesvirus 3. Vet Rec 166:178.
    doi: 10.1136/vr.c444pubmed: 20139382google scholar: lookup
  6. Barrandeguy M, Vissani A, Olguin C, Miño S, Pereda A, Oriol J, Thiry E. Experimental reactivation of equine herpesvirus-3 following corticosteroid treatment. Equine Vet J 40:593–595.
    doi: 10.2746/042516408x333399pubmed: 19031515google scholar: lookup
  7. Engelmann TM, Zoia AW, Venancio FR, Sallis ESV, Marchiori M, Lima M, Schild AL. Exantema coital em um equino. Pesq Vet Bras 44(Supl III):32.
  8. Ferreira C, Costa EA, França SA, De Melo UP, Drumond BP, Bomfim MRQ, Coelho FM, Resende M, Palhares MS, Santos RL. Equine coital exanthema in a stallion. Arq Bras Med Vet Zootec 62(6):1517–1520.
    doi: 10.1292/jvms.20-0056google scholar: lookup
  9. Kirisawa R, Toishi Y, Akamatsu A, Soejima K, Miyashita T, Tsunoda N. Isolation of equine herpesvirus 3 (EHV-3) from equine coital exanthema of two stallions and sero-epidemiology of EHV-3 infection in Japan. J Vet Med Sci 79(3):636–643.
    doi: 10.1292/jvms.16-0518pubmed: 28132964pmc: 5383190google scholar: lookup
  10. Machado M, Landi MFA, Moscardini ARC, Silva AS, Castro MB. Exantema coital (herpesvirus equino tipo 3) em equino macho castrado no Distrito Federal Savannah. J Res Dev 1:16.
  11. MGAP (2025) https://www.gub.uy/ministerio-ganaderia-agricultura-pesca/datos-y-estadisticas/datos/datos-preliminares-basados-declaracion-jurada-existencias-dicose-snig-2 . Accessed 10 Dec 2025
  12. Monteverde J, Garbers G, De Carlo J. Exantema coital en yeguas. S.P. C Analecta Vet 4:37–38.
  13. Pagamjav O, Kobayashi K, Murakami H, Tabata Y, Miura Y, Boldbaatar B, Sentsui H. Serological survey of equine viral diseases in Mongolia. Microbiol Immunol 55(4):289–292.
    doi: 10.1111/j.1348-0421.2011.00312.xpubmed: 21447048pmc: 7158856google scholar: lookup
  14. Silva-Filho GB, Bom HASC, Fonseca SMC, Costa EA, Santos BASAS, Santos RL, Evencio-Neto J, Mendonça FS. Equine coital exanthema caused by equid alphaherpisvirus 3: a report of an outbreak in northeastern Brazil. Pesq Vet Bras 41:e06877.
    doi: 10.1590/1678-5150-PVB-6877google scholar: lookup
  15. Thorsteinsdóttir L, Guðmundsson GÖ, Jensson H, Torsteinsdóttir S, Svansson V. Isolation of equid alphaherpesvirus 3 from a horse in Iceland with equine coital exanthema. Acta Vet Scand 63(1):6.
    doi: 10.1186/s13028-021-00572-4pubmed: 33531030pmc: 7856744google scholar: lookup
  16. Troncoso I, Calvanese R, Saravia F, Muñoz-Leal S, Zegpi NA, Ortega R. First molecular detection of Equine Herpesvirus type 3 (EHV-3) in Chile. Vet Med Sci 2023 9(2):717–720.
    doi: 10.1002/vms3.976pubmed: 36253808google scholar: lookup
  17. Vissani MA, Damiani AM, Barrandeguy ME. Equine Coital Exanthema: New Insights on the Knowledge and Leading Perspectives for Treatment and Prevention. Pathog 2021 10(8):1055.
    doi: 10.3390/pathogens10081055google scholar: lookup
  18. Żychska M, Matusz-Łukawska A, Pikuła I, Dzięgelewska-Sokołowska Ż, Azab W, Witkowski L. Equine coital exanthema – Eradicated or underdiagnoseddisease?. Equine Vet Educ 2024 37:812.
    doi: 10.1111/eve.14017google scholar: lookup

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