Herpes virus infection of the horse
Herpes virus infections in horses are caused by various herpes viruses . The infection with the equine herpes virus 1 (EHV-1) is economically most important .
Equine Herpes Virus 1 (EHV-1) and 4 (EHV-4)
Infections of the equine herpes virus 1 cause rhinopneumonitis (inflammation of the airways ) or virus abortion in mares . Equine herpes virus 4 can also cause rhinopneumonitis, but not viral abortion. The viruses enter the animal through the nose ( droplet infection ). They are widespread and endemic in many places , so reinfections are frequent. Respiratory diseases usually only occur in young or weakened animals. Virus abortion occurs in late pregnancy.
Rhinopneumonitis
The disease manifests itself mainly in the upper airways ( rhinitis , pharyngitis ), possibly also in pneumonia . The incubation period is 2-10 days. It manifests itself with a fever (up to 40.5 ° C). In addition, there are usually coughs and discharge from the nose and eyes. In addition, there is temporary neutropenia and lymphopenia . The disease usually heals in two (to five) weeks. A secondary bacterial infection may occur.
Virus abortion in the mares
If pregnant mares become infected with the virus, the foal may die between the seventh and eleventh months of gestation . EHV 1 attacks the mucous membranes of the uterus and placenta , so that the unborn child can no longer be adequately supplied with nutrients and dies. It can also lead to the birth of weak foals, which then usually die shortly after birth.
Paralytic Syndrome
In rare cases, EHV-1 can also lead to neurological diseases. As a result of myelitis (inflammation of the spinal cord ) leads to paralysis of the hind limbs.
prophylaxis
In the event of illness, care must be taken to isolate the animals concerned and avoid unnecessary contact with people. Anyone who had direct contact with the sick horses should not enter other stables. The quarantine must be maintained for up to three weeks after the acute infection has subsided.
The most important means of control is preventive vaccination , with both live and dead vaccines available. The vaccines do trigger the formation of antibodies , but cannot completely prevent reinfections with field viruses. However, the disease is usually harmless in vaccinated horses, virus abortions do not occur. It should be noted that the vaccination protection only lasts a maximum of nine months, the immunity of the mucous membranes is usually significantly shorter. Therefore the vaccination should be repeated every six months. Pregnant mares should be in the 3rd / 4th Month of pregnancy for the first time, in the 7th / 8th Vaccinated again in the month of pregnancy.
Equine Herpes Virus 2 (EHV-2)
The Equine Herpes Virus 2 is widely used and also comes without specific diseases in horses before. It is transmitted through direct contact with infected animals. Disease caused by the virus manifests as keratoconjunctivitis (inflammation of the conjunctiva and cornea of the eye) and diseases of the upper respiratory tract.
Equine Herpes Virus 3 (EHV-3)
The equine herpes virus 3 triggers a benign genital infection which is also known as coital rash or vesicular rash . The transmission takes place via the mating act ( deck epidemic ). Symptoms are pinhead to pea-sized vesicles, pustules or erosions of the vaginal vestibule or penis or penile foreskin . Infected animals remain virus carriers for life and must therefore be excluded from breeding.
According to Section 16 of the Animal Diseases Act (Austria) , the vesicular rash in horses is a notifiable animal disease .
literature
- Rolle / Mayr: microbiology, infection and disease theory . 7th edition 2002, Enke, ISBN 3777317950 .
