PATHOLOGY - Equine Abortion Flashcards
What should you always do if presented with an abortion case?
When presented with an abortion case, make sure to isolate the mare from other horses on the yard as there is a risk of infectious disease and be aware of the zoonoses risk
What is the difference between foetal mummification and foetal maceration?
Foetal mummification is drying out a preservation of the foetus after death in utero, whereas foetal maceration is the softening, decomposition and liquefaction of the foetus through the action of bacterial contamination
What can cause bacterial contamination and foetal maceration?
Cervical abnormalities
Ascending placentitis
What are the clinical signs of foetal maceration?
Brown or bloody vaginal discharge
Mare wil generally be systemically well
How do you manage macerated foetus?
Induce labour and manually remove the macerated foetus followed by uterine lavage
What should you do before subsequent breeding of a mare with a macerated foetus?
Endometrial biopsy with culture to determine if she is fit to breed
What are the three main categories of causes of equine abortion?
Infectious/inflammatory
Abnormal blood flow
Other (congenital, twins etc.)
Why do twin pregnancies cause abortion?
Twin pregnancies are generally non-viable and result in abortion due to placental insufficiency in the mare
(T/F) All equine twin pregnancies result in abortion
FALSE. Not all equine twin pregnancies result in abortion. Sometimes one can be born alive and the other still born, one can be born alive and the other mummified, the neonates can be severly premature, and very rarely two healthy twins can be born
What are the viral causes of equine abortion?
Equine herpes virus
Equine viral arteritis
What are the two strains of herpes viruses cause abortion in mares?
Equine herpes virus 1
Equine herpes virus 4
What is the pathogenesis of equine herpes virus?
Equine herpes virus causes vasculitis, microthrombosis and cotyledonary infarction resulting in abortion
What are the routes of transmission for equine herpesvirus?
Aerosol
Direct and indirect contact with nasal mucosa
Aborted foetuses
Transplacental transmission
What are the key characteristics that make equine herpes virus that make it so challenging to control?
- Acquired immunity to equine herpes viruses is transient and thus the mare can repeatedly contract the virus once the immunity has waned
- Equine herpes virus is a latent infection and thus can be reactivated in response to stress
Which does abortion due to equine herpes virus tend to occur?
Abortion due to equine herpes virus usually occurs during the last trimester
What is the condition of the aborted foal due to equine herpes virus?
Foal is usually quite fresh when aborted
What are the other potential consquences of equine herpes virus?
Stillborn foal
Alive foal with fatal viral pneumonia
How do you diagnose equine herpes virus as a cause of abortion?
Histopathology of aborted tissue
PCR of fresh liver and lung tissue
How do you control equine herpes virus?
Biosecurity
Hygiene
Isolate affected mares
Seperate pregnant mares from youngstock
Quarantine new horses
Vaccination
When should you vaccinate mares agaisnt equine herpes virus?
You should vaccinate mares agaisnt equine herpes birus at 5, 7 and 9 months of gestation
Which horse breeds have the highest prevalance of equine viral arteritis infection?
Standardbreds
Warmbloods
What are the routes of transmission for equine viral arteritis?
Respiratory secretions
Venereal transmission (test the semen before insemination)
Transplacental transmission
Carriers
Which individuals are carriers of equine viral arteritis?
Stallions
What are the potential clinical signs of equine viral arteritis?
Pyrexia
Anorexia
Periorbital oedema
Lower limb oedema
Conjunctivitis
Abortion
