EIV is rarely fatal, it is highly contagious and can lead to significant performance impairment and economic loss when outbreaks occur. Similar to influenza in other species, EIV is spread primarily via the respiratory route.
The AAEP considers equine influenza virus a risk-based disease, meaning it is not necessarily warranted for every horse. For horses considered at risk, annual vaccination is recommended.
Source: DVM 360, January 31, 2021. Link. EIV is an RNA virus in the Orthomyxoviridae family. The most commonly identified strain in recent history is H3N8. Young horses in frequent contact with other horses are considered high risk.
Also see: Search Results for: equine influenza, Animal Health Digest. Link.