Herpes in horses is caused by the Equine Herpesvirus (EHV), which can occur in various forms. The most common are EHV-1 and EHV-4, each causing different clinical pictures. EHV-1 can lead to severe conditions such as neurological disorders and abortions, while EHV-4 typically affects the respiratory system and leads to cold-like symptoms.
Symptoms
The symptoms of herpes vary depending on the type of virus and the affected body area. The most common signs include:
Respiratory diseases (with EHV-4):
• Fever
• Coughing
• Nasal discharge (often initially watery, later thick)
• Loss of appetite
• Weakness and apathy
Neurological symptoms (with EHV-1):
• Sudden onset of paralysis (mostly of the hind legs)
• Difficulty standing or walking
• Coordination disorders (ataxia)
• Loss of bladder and bowel control
Abortions (with EHV-1):
• Late-term abortion or the birth of weak foals, often without prior symptoms
• Symptoms can range from mild to severe and vary depending on the horse's condition and the form of the herpes virus.
Causes
Herpes in horses is caused by the Equine Herpesvirus (EHV). There are several types of this virus, each causing different clinical pictures:
- EHV-1:
Causes neurological diseases, such as Equine Herpesvirus Myelitis, as well as abortions or the birth of weak foals. - EHV-4:
Primarily leads to respiratory diseases (such as equine influenza).
The virus is mainly transmitted through droplet infection, direct contact with infected animals, or through contaminated equipment (e.g., feed troughs, water sources, gloves). The virus can also be spread by infected animals that do not show symptoms.
Diagnose
The diagnosis of herpes in horses is made by a veterinarian based on the symptoms and using various diagnostic tests.
Initially, a clinical examination is conducted, during which the veterinarian assesses the clinical picture and symptoms of the horse. Common signs of a herpes infection include fever, respiratory problems, and in severe cases, neurological symptoms.
An important diagnostic test is the PCR test. A swab is taken from the horse's nose or throat to detect the herpes virus. This method is very specific and allows for precise identification of the virus, enabling an accurate diagnosis. Additionally, in the early phase of infection, the virus can also be detected in the blood.
Serological tests can also be used. A blood test looks for antibodies against the herpes virus, which can confirm a previous infection. This is particularly helpful when a chronic infection or asymptomatic course is suspected.
Treatment
The treatment of herpes depends on the severity of the disease and the affected virus:
Respiratory diseases (with EHV-4):
Symptomatic treatment:
The focus is on alleviating symptoms such as fever and coughing, as well as administering anti-inflammatory medications.
Stall rest and isolation: The affected horse should be isolated and housed in a well-ventilated stall to prevent the spread of the virus.
Neurological symptoms (with EHV-1):
No specific antiviral therapy:
Currently, there are no specific medications to combat the virus. Treatment aims to relieve symptoms, such as through anti-inflammatory medications or supportive care.
Supportive care:
In more severe cases, more intensive care is required, such as assistance with mobility and bladder and bowel control.
Abortions (with EHV-1):
Unfortunately, there is no specific treatment for mares that experience a miscarriage. The affected mare should be isolated to prevent the spread of the virus.
Prevention
There is an option to vaccinate horses against EHV-1 and EHV-4. This is particularly recommended in breeding stables and for horses that regularly attend equestrian events.