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FAQ - Strangles

1. What is Strangles ?

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Strangles is an equine respiratory disease caused by  bacterium Streptococcus equi subspecies equi. This equine disease, also called "horse's angina",  mainly but not exclusively affects young horses under 5 years of age.

Strangles is very contagious, it is estimated that it takes at least 3 months to eradicate it from a workforce. This disease is generally not fatal but can in some cases (1 to 5%) lead to death following complications.

2. How is strangles transmitted?

Strangles is transmitted by sick individuals, convalescents but especially healthy carriers who harbor the bacteria in their guttural pockets without having symptoms. It is the latter which, combined with the high contagiousness of the disease, make the contagion difficult to control.

The modes of direct contamination of Strangles are:

  • By squirting/runny nose

  • Pus coming out of abscesses

  • Sputum

  • Milk during foal contamination


The survival of the bacterium responsible for Strangles is not well known, but it is estimated that under optimal conditions of temperature and humidity, it could survive for up to several months.

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 Strangles?

There are 3 clinical forms of Strangles:

  1. The Catarrhal Form

  2. The Erratic or Metastatic form

  3. hemorrhagic purpura


Erratic form and hemorrhagic purpura are considered complications of Strangles. They represent 15 to 20% of cases.

1. The Catarrhal Form  : This is the most common form of Strangles.


Symptoms :

  • Hyperthermia (fever 40°C)

  • Debilitated

  • Runny nose (flushing)

  • Pharyngitis (inflammation of the pharynx) with dysphagia (difficulty swallowing)

  • Hypertrophy (abnormal increase) of the mandibular and retropharyngeal lymph nodes (posterior region of the pharynx)


In the absence of treatment, the enlarged lymph nodes may become the seat of an abscess from which pus flows either outwards or internally into the guttural pockets (air pockets and nerve center located on both sides of the throat) so-called empyema of the guttural relatives.


  • Incubation period: 2 to 10 days

  • Clinical phase (when symptoms appear): about 20 days

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


2. The Erratic form  : also called bastard or metastatic form. It is a complication of Strangles which appears at the same time or after the Catarrhal form.


Symptoms :

  • Multiple abscesses

  • Inflammation of the lymph nodes with secretion of pus in several places (lungs, joints, nervous system, skin)

  • Pneumonia or Pleuropneumonia (pneumonia with inflammation of the lung membrane and effusion)


3. Hemorrhagic Purpura  : also called immune-mediated disorder, congestive Strangles or hemorrhagic Strangles. It is a very serious and rare form of Strangles which generally appears 2 to 3 weeks after the Catarrhal form.


Symptoms :

  • Vasculitis (inflammation of blood vessels)

  • Subcutaneous edema

  • Petechiae

  • Ecchymosis of the mucous membranes

  • Glomerulonephritis (disorder of microscopic blood vessels in the kidneys)

  • Urticaria

  • Inflammation of the oral mucosa and false nasal passages

  • Uveitis

  • Muscle damage (exceptional)

4. How to diagnose Strangles?

The symptoms of Strangles and its great contagiousness are quite remarkable and generally allow the veterinarian to quickly orient his diagnosis.

In order to confirm his diagnosis, the veterinarian will take various samples: purulent discharge, nasopharyngeal swabs, etc.

The methods used will then be bacteriology and the PCR test.

5. What are the treatments for Strangles?

There is no treatment for Strangles, the treatment will be symptomatic, that is to say, it helps to limit the outcome of the disease without treating the cause.

In most cases, no treatment will be necessary, the horse needs rest and care should be taken to provide water and moistened, easy-to-swallow food.

Abscesses that have not matured may need to be drained.

Anti-inflammatories can also be used to improve the condition of the equine and reduce fever.

6. What are the prevention rules against Strangles?

Medical prevention  : the vaccination. There is a vaccine against Strangles but it does not limit bacterial excretion when the horse is contaminated, its effect is therefore partial


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

  • Isolate sick equines

  • Do not use the paddock of a sick horse for 4 weeks

  • Use single-use materials

  • Wash and disinfect hands or use disposable gloves

  • Stop all movement of horses

  • Take the daily temperature of all horses

  • Disinfect any equipment used around a sick horse

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

Our Solution: NoViro

1. From Rhinopneumonia to Strangles

As explained on the Rhinopneumonia page, our product was first developed with the aim of protecting horses from Rhinopneumonia.

We then realized that our device is also effective against other respiratory diseases such as Strangles. Indeed, the Strangles are due to a bacterium gold, the bacteria are larger than the viruses.

Therefore, a filter capable of filtering viruses will be all the more so against bacteria.

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 embark on an FFP2 type mask for horses.

The idea seems simple, but we faced many challenges.

First of all, the design, it is not enough to make a giant FFP2 mask to be able to put it on a horse. We have developed a special frame to hold the filter in place. Inner frame keeps the filter away from the horse's nostrils, preventing the filter from touching the horse's nose  during inspiration. The outer frame 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 they 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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