There are four Herpesviruses that are widespread in the horse environment and that are associated with a variety of disease syndromes in horses. They are called Equid Herpesviruses 1, 2, 3 and 4 (EHV-1, EHV-2, EHV-3 and EHV-4).
Equine Infectious Anemia (EIA), sometimes called 'swamp fever' is an infectious disease that causes acute, chronic or symptomless illness, characterized by fever, anemia, swelling and weight loss in horses, ponies, mules and donkeys.
EVA is a highly contagious disease that can cause a 'flu-like' illness of varying severity and occasionally abortion or even death in horses. It is found in many different parts of the world and is endemic (widespread) in many continental European horse populations.
Strangles is an infection caused by bacteria called Streptococcus equi. It is highly contagious and the infection can be spread by horse-to-horse contact or by humans, tack, drinking troughs and other environmental factors.