Equine herpesvirus abortion in Australia 1977 to 1982.

This research explores the prevalence and impact of Equine Herpesvirus 1 (EHV1) causing horse abortions in Australia from 1977 to 1982, highlighting the emergence of an abortigenic subtype of the virus in the country in 1977.

Background of Equine Herpesvirus Abortion

• The study addresses abortion in horses caused by Equine Herpesvirus 1 (EHV1), which hadn’t been recorded in Australia until 1977.
• The presence of the virus, also known as equine rhinopneumonitis virus, had been known at least since 1962.

Outbreaks and Cases of EHV1

• It documents outbreaks of EHV1 abortion in New South Wales in 1977 and 1981.
• It also mentions sporadic cases of EHV1 abortion being confirmed in certain parts of Australia each year since 1975.

Introduction of Abortigenic Subtype EHV1

• The research concludes that an abortigenic subtype of EHV1 was introduced to Australia in 1977.
• It was also observed that the previously endemic respiratory subtype could occasionally cause abortion.

Diagnosis Methods

• Regarding diagnosis, virus isolation in a range of cell cultures and histopathological examination of tissue proved to be satisfactory methods for detecting EHV1 abortion.
• Lung tissue was identified as the specimen of choice for this testing.

Serological Differences

• The study found minor serological differences between the abortigenic and respiratory subtypes of EHV1, using cross neutralisation tests.
• This basically means the blood tests showed a slight difference in the responses to these different virus subtypes.

Serological Survey

• Lastly, a serological survey was conducted on 219 horses in Sydney of varying ages.
• The survey revealed that the majority of yearlings (one-year-old horses) had already acquired neutralising antibodies to both subtypes of EHV1.
• These findings suggest that most young horses were exposed to the virus and their bodies have therefore made antibodies that can block or suppress the activity of the virus.