190. Differential diagnosis of infectious abortions of horses (epidemiology, clinical signs, post mortem lesions).

Question 1

Diseases of the reproductive system?

Answer 1

Diseases of reproductive system

• Diseases of the reproductive system may cause significant economic losses in case of abortion or breeding restrictions due to infectious diseases
• The most important viruses affecting the reproductive system (and other organs):

- Equine herpesvirus type-1

- Equine viral arteritis

• Non-viral pathogens

• Bacterial abortion: Streptococcus, Staphylococcus spp, Escherichia coli, Pseudomonas aeruginosa, Enterobacter spp,

Klebsiella, Salmonella abortusequi, Actinobacillus equuli, Leptospira spp.

• Taylorella equigenitalis (contagious equine metritis/ CEM)
• Trypanosoma equiperdum (dourine)

Question 2

Equine Viral arteritis epidemiology?

Answer 2

Equine viral arteritis

• Epidemiology

• Arteriviridae family, Arterivirus genus
• Worldwide
• 2 genetic strains with same serotype: American and European
• Strains differ in severity of symptoms and prevalence of abortion
• 10-30% stallions are persistently infected ➝ transmission with semen

Question 3

Pathogenesis of equine viral arteritis?

Answer 3

• Pathogenesis

1. Virus can spread with aerosols, semen and amniotic fluid, placenta after abortion
2. After per oral or aerogen infection
3. Viraemia: virus into blood with macrophages
4. Virus damages endothel cells of arterioles ➝ oedema, inflammation and haemorrhages, abortion

Question 4

Clinical signs of equine viral arteritis?

Answer 4

Clinical signs

• Incubation: 6-8 days
• Fever, inappetence, nasal discharge, conjunctivitis, oedema (subcutaneous oedema of head, eyelids, limbs, abdomen, genitals/

scrotum)

• Areas are warm and sensitive
• May cause skin rash, colic, diarrhoea, jaundice
• Abortion in acute phase or few weeks after
• Weakness in foals
• Abortion sporadic

Question 5

Diagnosis and prevention of equine viral arteritis?

Answer 5

Diagnosis and prevention

• Initial phase ➝ isolation, IF, PCR, serology (VN, ELISA), specific symptoms
• Isolation of infected horses, general disease control measures
• Testing and screening persistently infected stallions ➝ serology, semen samples by PCR
• Active immunisation