Guarding against the scourge of strangles
Highly contagious, painful and potentially fatal, beware of this condition that can strike any horse, donkey or pony and stock of all ages
Published 04/01/2011 | 05:00
Strangles is so called because the sensation of having a bad dose must feel like being strangled -- or so the old story goes.
It's certainly true to say that it's a very unpleasant condition and that some horses affected with the condition struggle really badly to breathe, before some die.
It's a highly contagious, serious, but rarely fatal infectious disease that affects all, but usually young, equids. It is a disease that is endemic in Ireland, and is sometimes best left untreated. It can be prevented; and rarely recurs but carries a significant risk of setting up a 'carrier state'. By this I mean:
- That it is caused by an infectious agent (a bacterium called Strep equi)
- That it can readily pass between horses, ponies and donkeys
- That it is more common (as a clinical disease) in weanlings to three-year-olds
- That it causes significant illness, inconvenience and loss of performance but rarely death
- That it is considered a 'normal' or common disease in this country
- That it is well treated (with antibiotics) only in some animals
- That it can be managed by a combination of detection, biosecurity and vaccination
- That it can exist in a dormant form whereby a horse 'carries' the infection, shows no clinical signs but acts as a reservoir of infection spreading the disease to susceptible equids.
I'm often asked how common strangles is and that's a difficult one to answer because it all depends on what group of horses you are talking about and whether you include subclinical (carrier) cases as well as clinical disease cases.
Outbreaks occur on a sporadic but regular basis on stud farms, in livery yards, on training establishments and where just one horse is kept on private premises. Some would have it that the rate of infection has been on the increase recently; this may be so, but we just don't currently have the data to know.
In truth, there are likely to be peaks and troughs of infection, and the rate of disease seen will vary with the production, sales, movement, management and general health of our population of horses.
Strangles can vary between groups of horses, ponies or donkeys. Young horses from weaning up to four years or so of age seem to be more susceptible to clinical disease. Horses in poor health or bodily condition are more likely to get the disease and also to show it in a more severe form. And premises where there is frequent movement of horses (of varying age, type and origins) on/off or around the farm are distinctly more at risk of an outbreak.
Strangles carriers that show no clinical signs are more generally older horses. It is estimated that up to 10pc of horses that recover from a bout of the disease go on to become a carrier.