Equine influenza

Equine influenza is a highly contagious infectious disease of horses caused by equine influenza viruses. With the exception of Australia, Iceland and New Zealand, these pathogens are spread worldwide. The virus is mainly transmitted via droplet infection, for example when sick horses cough or snort. The virus can also be passed on indirectly - for example via secretions on hands, contaminated clothing or shared objects such as grooming equipment or transport vehicles.

The incubation period is usually one to three days. Typical symptoms are high fever (39-41 °C), a painful chesty cough, enlarged lymph nodes and occasionally oedema on the limbs. Some horses show no externally recognisable signs of illness, but can still spread the pathogen.

The pathogen is detected either by a nasopharyngeal swab or by detecting an increase in antibodies in two blood samples taken at different times. As this is a viral infection, treatment is primarily symptomatic. It includes resting the animals, strict isolation from the rest of the flock and the administration of anti-inflammatory and antipyretic medication. Depending on the course of the disease, the use of antibiotics may also be advisable to prevent secondary bacterial infections.

The most effective protective measure is regular vaccination. According to current scientific knowledge, it is the only reliable way to prevent infection with equine influenza viruses and their spread.

Equine herpesvirus infection

Equine herpesvirus infection is a viral disease of horses that is widespread worldwide, with infection often occurring in foals or young horses. After the initial infection, the virus remains in the body for life and can become active again under stress or if the immune system is weakened.

Of the various known types, EHV-1 and EHV-4 are the most common. The virus is excreted via the mucous membranes of infected horses, even if they show no symptoms. Transmission occurs through direct contact or indirectly via contaminated objects such as grooming equipment, troughs or clothing. EHV-1 can also cause a neurological form in addition to respiratory diseases, while EHV-4 mainly causes respiratory symptoms. Both virus types can also cause abortions in pregnant mares.

The diagnosis is made by direct detection of the pathogen from nasopharyngeal or uterine swabs, which are usually analysed in the laboratory using PCR. A causal cure is not possible, so treatment depends on the symptoms and the course of the disease.

Vaccination does not completely protect against infection or the signs of the disease, but it does reduce virus excretion and mitigate the course of the disease. In order to maintain protection in the horse population, regular vaccination of all horses is recommended.

Druse

Druse is a highly contagious bacterial infectious disease that occurs particularly frequently in young horses. It is caused by the bacterium Streptococcus equi ssp. equi and is spread worldwide. Infection occurs via secretions from the lymph nodes and respiratory tract, either through direct contact or indirectly via objects such as feeding troughs, grooming utensils or clothing.

At the beginning of the disease, there is usually a high fever of around 40 °C. As the disease progresses, the lymph nodes in the area of the mandibular branches and ganaches swell and abscesses form, which can break outwards or inwards. If they penetrate the neighbouring air sacs, purulent secretions often accumulate there.

The diagnosis is made by examining abscess swabs, rinse samples from the nasopharynx or air sacs. The bacteria are either cultured in the laboratory or detected using PCR. Treatment depends on the severity and course of the disease.

In most cases, the course of druse is uncomplicated and the prognosis is good. Severe courses of the disease are rare.

West Nile fever

The West Nile virus originates from Africa and is transmitted by mosquitoes. It can cause a febrile general illness in both humans and horses, and birds can also fall ill. Direct infection from person to person, from horse to horse or between person and horse is not possible.

Around two thirds of infected horses show mild, flu-like symptoms such as fever, fatigue and loss of appetite. In about one third, however, there is a severe neurological course with inflammation of the brain and spinal cord. Affected horses can show symptoms such as an unsteady, uncoordinated gait (ataxia), swaying, lying still, muscle tremors, facial asymmetries or behavioural changes.

The diagnosis is made by detecting the virus or antibodies in the blood. Depending on the severity of the disease, affected horses often require intensive veterinary care. While the febrile form usually heals without complications, the neurological form can be fatal or cause permanent damage.

Vaccination is recommended to protect against infection, especially for horses in or near affected areas. If possible, vaccination should be carried out before the start of the mosquito season.