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FAQ - Rhinopneumonia

1. What is Rhinopneumonia?

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Rhinopneumonia is an equine respiratory disease of the herpesvirus family (Herpesviridae). From an etymological point of view, the word Herpesviridae comes from the Greek and means "to crawl" like a snake. This refers to the latent nature of this type of disease, after the primary infection, the virus "hides" in the body in a latent form, which camouflages it against the immune system and antivirals.

It is estimated that 60 to 70% of horses carry Rhinopneumonia in latent form.

The virus can then be reactivated at any time by stimuli such as a sudden stress for example. This is called endogenous reinfection because the phenomenon occurs inside the body without outside intervention.

There are 5 strains of equine herpesvirus: HVE-1, HVE-2, HVE-3, HVE-4 and HVE-5.

The two most common forms, commonly called Rhinopneumonia, are:

  • Equine herpesvirus type 1 (HVE-1)

  • Equine herpesvirus type 4 (HVE-4)  

2. How is Rhinopneumonia transmitted?

Rhinopneumonia is an epizootic, that is to say that this virus spreads between animals by epidemic. It is one of the most contagious diseases in equines.  Man may be the vector but will not be contaminated.

As explained above, 60 to 70% of horses carry the Rhinopneumonia virus in latent form. The virus can be reactivated at any time by stress in particular.

The main modes of direct contamination are:

  • By nasal secretions

  •   By microdroplets

  • Abortion or contaminated placenta

  • Uterine secretions from an aborted mare


It is important to specify that the Rhinopneumonia virus can survive for several days outside the body if the conditions are favorable. Therefore, indirect contamination is possible.

The main modes of indirect contamination are:

  • By humans when they carry the virus on their clothes or hands

  • Contact with soiled material

3. What are the symptoms of Rhinopneumonia?

Rhinopneumonia viruses HVE-1 and HVE-4 can generate 3 clinical forms:

  1. The respiratory form

  2. The abortive form

  3. The neurological form


1. The respiratory form : this is the most frequent form of Rhinopneumonia,  it touches  most often young horses.  This form, in the majority of cases, is the result of the  Equine herpesvirus type 4 (HVE-4), but type 1 (HVE-1) can also be the cause.


Symptoms :

  • Runny nose

  • Hyperthermia (fever > 38.5°C)

  • Cough (not systematic)

  • Dyspnea (difficulty breathing)

  • Abatement

  • Loss of appetite


Symptoms are similar to equine flu but less pronounced.


  • Incubation period: 2 to 10 days

  • Clinical phase (when symptoms appear): 1 to 2 weeks

  • Contagiousness: during the clinical phase and up to 21 days later


Vaccinated horses can be totally asymptomatic, however, we will observe counter-performances in sport.


2. The abortive form : This form, in the majority of cases, is the result of the  Equine herpesvirus type 1 (HVE-1) but type 4 (HVE-4) can also be the cause. It is  the leading cause of infectious abortion in horses. It has no warning signs.

Abortion generally occurs at the end of gestation between the 9th and 11th month but it has already been observed from the 4th month.

Up to 90% of abortions are observed in a non-vaccinated population.

Incubation period: up to several months



3. The neurological form : This form is the most serious of Rhinopneumonia because the vital prognosis of the horse can be engaged. As an example, the mortality rate during the epidemic peak of the Valencia international jumping competition in 2021 was 10%.

The neurological form of Rhinopneumonia is exclusively due to equine herpesvirus type 1 (HVE-1).


Symptoms: very variable from one individual to another

  • Disturbance of locomotion up to paralysis

  • Ataxia (problem coordinating movements causing loss of balance and/or falling)

  • Fever

  • Urinary incontinence


There is no warning sign of the neurological form of Rhinopneumonia, the symptoms generally appear two weeks after contamination. The recovery of the equine will vary from complete to non-existent.

4. How to diagnose Rhinopneumonia?

When the veterinarian suspects a case of Rhinopneumonia, he will confirm his diagnosis by laboratory analysis. He will perform a PCR test by taking nasal and blood swabs for respiratory and neurological forms. The abortive form will be detected by taking tissue samples from the liver or lung of the foetus.

5. What are the treatments for Rhinopneumonia?

There is no treatment for Equine Rhinopneumonia, the treatment will be symptomatic, ie it helps to limit the outcome of the disease without treating the cause. We will mainly use analgesics to fight pain, anti-inflammatories against fever and antibiotics in case of bacterial superinfection.

In the case of Rhinopneumonia in neurological form, the chances of survival can be increased by keeping the horse upright with the help of a harness.

6. What are the prevention rules against Rhinopneumonia?

  • Medical prevention: vaccination. There is a vaccine against Equine Rhinopneumonia which will help limit the severe forms of the respiratory and abortive forms.


  • Health prevention: several biosecurity rules can be put in place to limit the spread of Rhinopneumonia:

    • Isolate sick equines

    • Do not use the same material for several horses

    • Quarantine any horse newly arrived at the stables

    • Disinfect any equipment used around a sick horse


Disinfect all surfaces that may have been contaminated by a sick horse

Our Solution: NoViro

1. Our observation: Rhinopneumonia and Covid-19 are similar

During the epidemic peak that occurred at the international show jumping competition in Valencia in 2021, we, like most horse owners, sought solutions to protect our horses. We then realized that there was no solution to limit the risk of contamination in competitions.

By educating ourselves a little more, we realized that the spreading method of the Rhinopneumonia virus was similar to that which we had known for some time in humans, Covid-19.

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Then, pushing our research even further, we realized that Rhinopneumonia virus and Covid-19 are similar in size, Rhinopneumonia is even larger in size.


The solution then seemed obvious to us, what works to prevent the spread of Covid-19, will work for Rhinopneumonia!

2. Our solution: an FFP2 type mask suitable for horses

One of the great tools used to limit the spread of Covid-19 is respiratory protection.  We have therefore decided to develop an FFP2 type mask for horses.

The idea seems simple, but we faced many challenges.

The first one : the design; it is not enough to make a giant FFP2 mask to be able to put it on a horse. We developed a special casing to hold the filter in place. The inner casing keeps the filter away from the horse's nostrils, preventing the filter from touching the horse's nose  during inspiration. The outer casing protects the filter from external damage (shock, friction).  

The second challenge, and surely the most complicated, was to produce a large volume filter while maintaining reasonable prices. For information, a NoViro filter is equivalent to 7 human FFP2 masks!

Last challenge, and not least, we had to work on the composition of our filter so that it let through the 60 liters of air per minute that a horse inhales and exhales every minute. All this while maintaining a filtration rate of more than 99%!

3. Our certifications

After numerous developments and prototypes, we sought to have our products certified by reference companies.

Filtration has been tested by the Société Générale de Surveillance (SGS) according to standard EN14683 which is the European standard used for surgical masks for human use. SGS is the world leader in inspection and testing services. It is also one of the companies recognized by the French Government for the certification of masks for human use.



  • Filtration over 99%

  • Breathability conforms to EN14683 Type IIR



We commissioned the National Veterinary School of Lyon to confirm that there were no adverse effects or discomfort when wearing NoViro. The National Veterinary School of Lyon, in Marcy-l'Etoile, welcomes 1,500 horses each year. On average, one horse per day goes through the emergency room. Some horses come from Spain or Germany.  This "CHU (University Hospital Center) for horses" was the first establishment of this type in France more than 4 years ago. In March 2021, during the epidemic peak of Rhinopneumonia that occurred in Valence, the French Equestrian Federation called on the National Veterinary School of Lyon to welcome and manage the quarantine of French horses during their repatriation to France.


Results :

  • Very good tolerance of the mask at rest

  • Very good tolerance of the mask during active walking exercise

  • No noticeable effect on arterial oxygenation level

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