Rhinopneumonia (EHV) is a herpes virus infection caused by two different herpes viruses (EHV1 and EHV4) and has three manifestations:
- cold form
- abortion form
- neurological form
The cold form is very common in young horses in particular and is mainly caused by EHV4. The horses do not always have clinical signs, but the following symptoms may occur: fever, nasal discharge, respiratory symptoms, loss of appetite and / or swollen legs. Very rarely, infection with EHV4 may cause abortion and / or neurological signs.
EHV1 is a more dangerous variant. This can, among other things, cause respiratory symptoms, but is also often the cause of an abortion or very weak foals that often die. This variant can also cause neurological symptoms. This usually starts with a floppy tail and ataxia. More serious paralysis symptoms may also occur. Usually only the back legs are affected, but in the most severe cases the front legs can also be involved.
Fortunately, the neurological form occurs only occasionally. All horses in the Netherlands regularly come into contact with these viruses (almost all horses with EHV4 and 20-40% of horses with EHV1). Unfortunately, it is not known why an equestrian centre is sometimes affected by abortions or paralysis problems.