Equine neonatal isoerythrolysis

Question 1

What is equine neonatal isoerythrolysis?

Answer 1

Life threatening haemolytic anaemia (Bailey et al. 1988) which only occurs in foals (Snook 2001) and the disease normally occurs after 12 hrs of being born (Becht 2009).

Question 2

When do foals start to present symptoms of Equine neonatal isoerythrolysis?

Answer 2

After 12 hrs of being born when they have ingested the mothers colostrum.

Question 3

What is the cause of equine neonatal isoertytherolysis?

Answer 3

Mother produces anti-RBC Ab’s which are injested by the foal.
“Foal inherits cell factor that the mare lacks, Ab’s in mares colostrum are ingested by the foal, this causes destruction of the foals RBC’s due to incompatibility of mothers Ab’s to foals RBC’s (Bailey et al. 1988).

Question 4

What does the ingestion of the mares Ab’s induce?

Answer 4

A hypersensitivity reaction which causes the rupture/ attack of the RBC’s by the foals IS.

Question 5

What are the clinical signs of equine neonatal isoertherolysis?

Answer 5

• RBC lysis
• Anaemia
• Lethargy
• Tachycardia (2ndary to hypoxia)
• Tachypnea (2ndary to hypoxia)
• Hypoglobinemia (Becht 2009)
• Haemoglobinuria - VERY RECOGNISABLE AS MAKES URINE RED
• Icterus (Becht 2009)

Question 6

How do the mares become sensitised to the red blood cell antigen?

Answer 6

• Transplacental haemorrage (more at risk with this as Ab’s have time to develop)
• Contamination of bodily fluids at brith (causing a risk to future foals as will occur again)

Question 7

How would you diagnose Equine neonatal isoerythrolysis?

Answer 7

• BT of mare
• BT of foal (see damaged/ lack of RBC’s)
• Analyses Ab’s (anti-RBC’s) in colostrum

Question 8

How can you treat Equine neonatal isoerythrolysis?

Answer 8

• Corticosteroids (dexamethasone
• Supportive care (fluid therapy, clean environment, keep foal warm)
• Blood transfusions

Question 9

How can you manage the risk of Equine neonatal isoerythrolysis?

Answer 9

• Screen mares, if positive then withold the foal from suckling.
• Donor colostrum if positive to ensure foal gets essential Ab’s
• Different sire in future

Question 10

Why may treatment not be successful in Equine neonatal isoerythrolysis?

Answer 10

• Foal too far along in disease
• Incompatible blood transfusion
• Failure on responding to steroids
• Get 2ndary disease/ infection

Question 11

What other causes may cause IMHA/ Equine neonatal isoerythrolysis?

Answer 11

Bacterial infections

Ingestion of toxins that cause destruction of RBC’s e.g red maple.