Viral causes of reproductive diseases in equine

Viral Causes of Reproductive Diseases in Equine.
Reproductive diseases of equine.
equine reproduction
Horse viral diseases related to reproduction

1. Viral Causes of Reproductive Diseases in Equine Dr. Muhammad Awais

2. Viral Causes of Reproductive Diseases Two important viral diseases of breeding horses Equine herpes virus infection Equine viral arteritis

3. Equine herpes virus infection Equine herpes virus 1, 3 and 4 causes reproductive problems Equine herpes virus 1 & 4 (EHV1 & EHV4) causes Viral Abortion Equine herpes virus (EHV3) causes Coital Exanthema

4. Viral Abortion Also called rhino-pneumonitis Caused by EHV1 & 4. EHV-1 , causes abortion , respiratory signs, neurological signs EHV-4, usually causes respiratory disease only but can occasionally cause abortion. Abortion – last trimester Infect multiple types of cells Lytic and latent cycle Latency – trigeminal ganglia and CD8+ cells

5. Transmission Horse - to – horse Ingestion and inhalation Aborted material, semen, aerosol droplet Reservoir – latently infected horses Stress, transport can reactivate latency Less persistent in environment Infection acquired in first weak of birth

6. Pathogenesis Inhalation Replicate in upper resp. tract mucosa In uterus – vasculitis – abortion Disseminated in all organs including trigeminal ganglion, CNS, uterus during viremia Enter to lamina propria , endothelial cells, CD8+ cells Brain – vasculitis , thrombo -ischemia, encephalopathy Virus Tiwari S.C, et al.,

7. Clinical signs Nasal discharge, conjunctivitis, lymphadenopathy, no cough Abortion – last trimester Neonatal infection – fatal Stallion – poor semen quality CNS – ataxia, paralysis, bladder dysfunction

8. Diagnosis There is no test to detect latent carriers Virus isolation PCR Serology

9. Multifocal hemorrhages, rubbery lung Multiple necrotic foci in liver Hemorrhage and necrosis of brain stem Aborted fetus, enclosed in amnion

10. Lesions Necrotic foci in liver Eosinophilic inclusions in hepatocyte Vasculitis in CNS Nuclear debris in splenic follicle lymphocytolysis  EHV-1 particles nucleus. Organelles of the cytoplasm degeneration hydropic dilation of sER,mitochondria , detached ribosomes of rER

11. Control and prevention Keep weaned foals and yearling away from pregnant mares Aborted material and contaminated bedding should be burned Aborted mare should be isolated for at least 1 week with strict control admission to box and routine hygienic measures Outside mares should not allowed onto infected premises until at least 1 month after the last obrtion Vaccination two vaccines against EHV1 are available dead and attenuated Ideally all horses on premises should be vaccinated.

12. Coital Exanthema Caused by herpes virus (EHV3) Spread by coitus Vesicular Lesions on vulva , vestibule,and penis. These vesicles rupture and produce infected ulcers. Usually are healed with local antibiotic treatment. Coitus Cannot be performed by infected mare or stallion. Condition is resolved in 14 days.

13. Viral arteritis Caused by Equine arteritis virus belong to genus Arterivirus , family Togaviridae The virus which causes EVA was first isolated from horses in Ohio in 1953 About 80% abortion during clinical disease Characterized by depression, edema of limbs, intense pink or red conjunctiva, palpebral edema, enteritis , pneumonic complications and abortions

14. Transmission Via respiratory route or by ingestion Venereal transmission by stallions Tissues and fluids of aborted fetus contained large mass of virus Virus shed in the urine Holyoak G.R., et al.,

15. Pathogenesis Virus Nasopharynx Lungs/ bronchial lymph nodes Blood ( viremia ) Body tissue/ fluids Abortion in mare Shed in semen

16. Lesions Congestion, petchiae in conjunctiva, resp tract and guttural pouches, Hydrothorex , petichae in pleura, heart, pericardium and lungs, Ascites Enlargement of LN Petichae on endocardium, epicardium, mesentery Small intestine, caecum and colon oedematous and congested

17. Microscopically Small arteries and necrosis and deposition of eosinophilic mass in tunica media with cellular infiltration in adventitia Platelet thrombi in lumen Abortion -necrotizing myometritis

18. Control and prevention A dministration of a modified live and formalin-inactivated vaccine use in non pregnant mares and in stallions. Vaccinated horses or any other horses with titers to EAV may not be eligible for export to certain countries.