An outbreak of Equid herpesvirus abortion in New South Wales.

The research discusses an outbreak of Equid Herpesvirus Abortion (EHV-1) in New South Wales that affected 33 out of 44 mares at a Thoroughbred stud, leading to either abortion or the loss of foals within a day after birth. The study confirms the presence of EHV-1 through a virological examination of six foals.

Understanding the EHV-1 Outbreak

• The study is centered around an outbreak of EHV-1, a type of herpesvirus, which commonly affects horses leading to abortion or loss of foals within one day of birth. It occurred at a Thoroughbred stud in New South Wales.
• This outbreak was significant because 33 out of 44 mares at the stud were affected, marking a high incidence rate.

Pathological and Histological Changes

• Upon examination of the affected mares, noticeable gross pathological and histological changes suggested an EHV-1 infection. The changes were effectively in line with typical symptoms of the disease.

Virological Examination

• To confirm the diagnosis, a virological examination was conducted on six foals from the affected group. The EHV-1 was successfully isolated and typed from these samples.
• Typing of the virus was done by restriction endonuclease analysis. This is a type of DNA fingerprinting used to identify and classify different strains of viruses.

No Prior Occurrence of EHV-1

• A significant finding from the study is that there was no prior occurrence of EHV-1 abortion at this stud, making this an isolated outbreak.

Source of Infection

• Despite investigating the outbreak, the researchers were unable to identify the source of the infection.

This research provides an important case study for outbreaks of EHV-1, a major cause of abortion in horses. The findings demonstrate the extent to which EHV-1 can impact an equine population and raises questions about how the disease was introduced to the stud.