Pathological changes in horses dying with equine influenza in Australia, 2007.

This research article investigates the pathological effects of the 2007 equine influenza outbreak in Australia, focusing on the impact on young foals and mature horses, and the risk to pregnant mares and their offspring.

Pathological Changes in Young Foals and Mature Horses

• Researchers looked into the pathology reports from the 2007 outbreak of equine influenza (EI) in Australia to understand the disease effects.
• The findings revealed that young foals in populations not previously exposed to the equine influenza virus were highly susceptible to developing broncho-interstitial pneumonia, a severe lung condition.
• The condition, while common in young horses, was found to be a rare manifestation of the EI virus infection in mature horses.
• All horses, irrespective of age, were found to be at risk of developing a secondary bacterial bronchopneumonia, a form of pneumonia caused by bacterial infection.
• The risk of death due to this bacterial infection was found to be higher in mature horses.

Impacts on Pregnant Mares and Neonatal losses

• The study also focused on the impacts of EI outbreaks on heavily pregnant mares.
• It was found that EI outbreaks can lead to higher neonatal losses due to premature placental separation and dystocia (difficult or abnormal childbirth or labour).
• These complications cause fetal hypoxia, a condition in which the fetus does not receive enough oxygen, which can result in stillbirth or death soon after birth.

This research provides valuable insights into the impact of equine influenza on different horse populations, and can guide future preventative measures and treatment strategies.