Strangles
News has heard there is strangles about. While any outbreak will be dealt with directly by your vet, the implications for other horse owners are often worryingly unclear. How does the disease spread; how can it be avoided?
Firstly, strangles is a virulent, highly invasive bacterial infection that causes, most noticeably, large glandular swellings in the region of the jaws accompanied by profuse thick, white discharges from the nostrils. It may be introduced through an animal incubating the disease, or one in the recovery stages that is still shedding the organism. It can come on the hands, clothes or footwear of workers or visitors. It could easily enter on the wheels of a car, or lorry, and get carried onwards on the feet of workers, dogs or horses.
Contaminated material is highly infectious. Spread, within a yard, is most likely to occur by handling buckets, brushes, doors etc where discharges have landed – remembering also that infected horses may cough or blow the organism out when clearing their nostrils or throat. Being a bacterium, there is a limit to the distance this can happen (maybe 5 to 20 metres). But the ease of human transmission makes it vital a plan for control is put in place as soon as disease is suspected.
How it Starts and Develops
- There is an incubation period of 7 – 10 days (may vary from 2 – 20).
- The first sign is often a sore throat; infected horses make throaty sounds and may be unable to swallow or drink.
- Temperature rises to as high as 106F.
- Within days, a watery nasal discharge turns to the consistency of pus.
- Lymph glands start to swell between and behind the jaw bones.
- These (and other) glands become hot, tense and painful; are likely to burst and discharge pus.
- Internal glands may swell and burst too.
- Recovery is slow, but mostly uncomplicated – there is a low mortality rate, only a small number of badly affected horses succumb.
- Horses with thick nasal discharge and no visible gland swelling can be infected with this disease; making accurate diagnosis imperative.
- Foals (and old horses) are likely to suffer a severe form that can prove fatal.
What to do
- Consult your vet immediately at any suggestion your horse has strangles.
- The vet may diagnose the condition from symptoms or may take samples to confirm an opinion.
- From the outset, observe strict hygiene and use disinfectants on hands and footwear.
- It is always wise to be cautious and isolate infected individuals until the disease is confirmed or eliminated.
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- Stay away from infected premises, as far as possible.
- Avoid obviously infected animals.
- Assume you are infected after contact.
- Wash all clothing - in a hot wash; make sure the soles (as well as the uppers) of footwear get fully disinfected.
- Be meticulous about personal cleanliness.
Horse movements
- As the infection spreads from one horse to another directly, it is important to plan ways of breaking the cycle immediately symptoms are seen.
- No infected horse should ever be moved into contact with uninfected horses.
- Uninfected horses should not be moved onto an infected yard.
- Do not move recovering horses into contact with uninfected animals.
- Do not graze infected or recovering horses on land needed for uninfected animals within 6 months.
- Fully disinfect any transporter used to move an infected horse.
Infected Yard
- If possible, keep the first infected animal isolated in an enclosed stable.
- Ensure adequate ventilation, don’t let horse have head over door.
- Don’t keep in a barn with other horses.
- Provide individual buckets and other implements.
- Place a footbath outside the door.
- As far as practical, have the horse attended by one person, who undergoes a rigorous system of disinfection after every visit to the stable.
- A disposable suit may be used, or waterproofs that can be pressure washed, ensuring full disinfection.
- Carry out rigorous disinfection of stables between horses, cleaning all areas a horse can reach.
Once strangles has spread within a yard
- If the infection can be confined to housed animals, careful hygiene may be successful in eliminating the organism.
- The organism may survive on wooden surfaces for 6 to 9 weeks, depending on conditions.
- It spreads easily on grazing land, so never turn infected or recovering animals out with others.
- Infected horses may shed infection for up to 8 months, although this is unusual; 6 weeks after discharges go is more the norm.
- To monitor the situation, your vet can help by taking swabs to gauge the presence of infection.
A fuller account is available in my book Respiratory Disease, published by J A Allen. If you have questions about dealing with the problem, email and I will try to help
Peter Gray
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