The health of horses is a priority for all owners and professionals in the equestrian world. One of the most worrying diseases is equine rhinopneumonitis. This viral infection, although sometimes little-known, can have serious consequences, both for horses and for equestrian structures. This article explains the mechanisms of the disease, symptoms, and essential preventive measures to protect your horses.

You can also find feather information on our previous article on this topic, here.

What is equine rhinopneumonitis?

Equine rhinopneumonitis is an infectious disease caused by two types of herpesviruses: equine herpesvirus type 1 (HVE1) and type 4 (HVE4). Highly contagious, it mainly affects the respiratory tract of horses, but can also cause abortions in mares and, in some cases, serious neurological complications.

The two types of viruses: 

• HVE1: Known to cause respiratory disorders, sporadic abortions and neurological syndromes.
• HVE4: Associated with mild respiratory infections, particularly in young horses.

Both viruses share similar transmission mechanisms, but HVE1 is often the more feared because of its potential severity.

How is rhinopneumonitis transmitted?

Transmission is mainly airborne, via respiratory droplets expelled when horse’s coughs or sneezes. However, the virus can also spread indirectly via:

• Contact with contaminated surfaces, such as feed troughs, water troughs or equipment.
• Clothing and footwear worn by riders or caretakers who have handled infected horses.

Factors favoring the spread 

Equestrian gatherings, such as competitions, training courses or fairs, considerably increase the risk of contamination. In addition, factors such as stress, poor hygiene or a weakened immune system make horses more vulnerable to the disease.

What are the symptoms of equine rhinopneumonitis?

Rhinopneumonia can take several forms, depending on the type of virus and the horse’s state of health:

Respiratory symptoms

• High fever (up to 41°C).
• Dry or hacking cough.
• Clear or purulent nasal discharge.
• Fatigue and reduced performance.

Reproductive symptoms

• Late abortions (often in the last months of gestation).
• Stillbirths or non-viable foals.

Neurological symptoms (myeloencephalopathy form)

• Ataxia (coordination disorders).
• Weakness of hind limbs.
• Partial or complete paralysis.

Respiratory and reproductive forms are the most common, but the neurological form, although rare, is often fatal.

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Diagnosis and treatment

In the event of suggestive symptoms, it’s crucial to consult a veterinarian as soon as possible. The veterinarian can confirm the diagnosis using specific tests, such as:

• Nasal swabs to identify the presence of the virus.
• Blood tests to detect an immune response.

In the event of a positive diagnosis, a protocol of isolation and symptomatic treatment (anti-inflammatories, respiratory care) will be implemented.

Prevention: a major challenge

Prevention remains the best way to limit the spread and impact of rhinopneumonitis in stables.

Vaccination

Although the equine herpesvirus vaccine does not guarantee total protection, it reduces the severity of symptoms and limits the spread of the virus. Horses should be vaccinated regularly, especially those taking part in competitions.

Stable hygiene and management

• Cleaning and disinfection: Stalls, equipment and communal areas should be disinfected regularly.
• Flow management: Limit comings and goings in the stables to reduce the risk of cross-contamination.
• Isolation of new arrivals: Systematic quarantine for all horses entering a stable.

Monitoring and reporting

It is essential to regularly monitor the health of your horses, and to report any suspicious cases to a competent organization such as RESPE. This epidemiological network plays a key role in managing equine epidemics.

Why act quickly?

In addition to the health risk, an epidemic of rhinopneumonitis can have serious economic consequences for owners and equestrian facilities:

• Cancellation of competitions and associated financial losses.
• High veterinary costs.
• Loss of valuable foals for breeders.

By acting quickly and adopting preventive practices, it is possible to limit these impacts and protect the entire equestrian community.

Conclusion

Equine rhinopneumonitis is a fearsome disease, but one that can be managed through vigilance and rigorous preventive measures. Vaccination, hygiene and isolation of sick horses are essential to limit its spread. Finally, the role of owners and professionals is crucial: by reporting any suspicious cases and complying with health recommendations, you can help protect your horses and those of others.

For further information and practical resources, visit the RESPE website.