With strangles awareness week coming up in May, equine vet Dulcie discusses the disease in a three part series. Part one gives us a general overview of equine strangles.
Strangles is a commonly diagnosed infectious disease in horses, with greater than 600 recorded outbreaks on average per year in the UK. It can affect any horse on a yard and is not a disease of poor welfare. Unfortunately, there is still a lot of stigma associated with the disease which often stops people speaking out about strangles, and further contributes to its spread. Strangles awareness week aims to combat this stigma by giving people a platform to discuss their experiences and promote their support for people affected by strangles. As well as being an unpleasant disease for the horses affected, it can result in movement restrictions and therefore have financial implications for riding schools, yards and equestrian businesses.
Causes and spread
Strangles is caused by the bacteria Streptococcus equi subspecies equi. The bacteria can be transmitted in two ways:
- Directly – contact with other horses through nasal discharge or abscesses.
- Indirectly – shared equipment (brushes, tack feed buckets), transport, contaminated water sources and people (through contaminated clothes and boots).
Strangles is not an airborne disease, but the bacteria can be spread further than expected when the horse snorts or coughs.
It can take anything from 3 to 21 days after a horse has been infected for it to show clinical signs. Horses can also remain infectious for 3-6 weeks after clinical signs have resolved which is why prolonged isolation and tests to ensure resolution of the disease are really important in controlling the disease.
Some of the common signs are:
- Fever (often the first sign)
- Loss of appetite
- Nasal discharge
- Lymph node swelling around the head and throat – these may also become abscesses
- In rare cases – struggling to breath if abscesses compress the larynx
Often clinical signs are enough to suspect strangles, especially if multiple horses on a yard are affected. However, some tests may be taken from your horse to confirm disease status and also from other horses to give an idea of how far it has spread on the yard. Some tests have their limitations which is why different ones are used in different scenarios.
The three main tests are as follows:
- Swabs – to culture bacteria
- Guttural pouch endoscopy – to examine the guttural pouches for pus and take a sample to detect the bacteria
- Blood tests – check for antibodies
The main aims of treatment are to keep your horse comfortable and helping the disease to clear. Treatment may vary depending on each case. Below are some of the main treatments:
- Anti-inflammatory drugs (e.g Equipalazone, Finadyne) – these help to control fever and also alleviate pain associated with the disease.
- Abscess management – hot packing abscesses to help them to rupture, cleaning and flushing open abscesses regularly.
- Feeding – feeding the horse from the floor to help drainage of pus, give sloppy feeds if the horse is struggling to eat.
Antibiotics are rarely used, only in very severe cases. This is because antibiotics do not penetrate pus well and they may even prolong the disease process.
There are a number of ways we can try to reduce the risk of bringing strangles onto the yard:
Away from the yard
- Take and use your own water, feed and buckets and do not share these with other horses
- Do not allow nose to nose contact with other horses
- Make sure you wash your hands after handling another horse before touching your own
- Disinfect boots after each show
- If stabling your horse away, it is a good idea to take disinfectant with you and use it to disinfect the stable before putting your horse in it
- If using hired transport, ensure it has been thoroughly disinfected between horses
- Returning home – check your horses’ temperature regularly and monitor for clinical signs of infection – Horses usually develop a fever 24-48hrs before they start shedding strangles bacteria
- Separate grooming kits, tack, buckets etc for each horse
- Any horse with nasal discharge, cough or fever should be isolated promptly and investigated ASAP
- Anyone who cares for horses at multiple establishments should follow good biosecurity between yards e.g washing hands, disinfecting boots, changing outer clothing
- Minimum of 3 weeks isolation period – this should be a completely separate area away from all other horses on the yard and only one person should handle the horse, and ideally not deal with other horses during this period
- Strangles blood test – just before moving and then at the end of the isolation period before mixing with other horses
The BHS have created a ‘Strategy to eradicate and prevent Strangles’ which can be downloaded from their website.