What Is Strangles?
Strangles is a contagious bacterial infection caused by an organism called Streptococcus equi equi. Infection is passed by direct contact – either horse to horse or via people and equipment. It cannot travel over any significant distance in the air, no more than a few meters. Strangles is not a notifiable disease. There are no statutory regulations as to how infection must be dealt with and vets have no power to control outbreaks, however there are recognised guidelines on how best to manage infectious outbreaks.
Signs and Symptoms
- High temperature (often over 40degrees)
- Off food and depressed in themselves
- Profuse nasal discharge
- Swellings around or under jaw which may discharge pus
- Difficultly breathing
Some horses do not show all these symptoms. Some may only show mild symptoms and some are much more severely effected.
Managing an Outbreak
When to Re-Open Your Yard
- Bastard strangles: This is a potentially fatal form of strangles. The infection spreads to lymph nodes in the body creating abscesses within the body.
- Purpura: This causes bleeding in the gums, mucosa and lungs of horses. It also causes swelling of the distal limbs, under the belly and the muzzle. This is also potentially fatal although treatment can be attempted using high doses of steroid and antibiotics.
Roo is a 7year old pony who presented with a satsuma sized lump under her jaw. She was a little quieter than normal but was eating ok and drinking normally. When examined she was very slightly reluctant when her lump was palpated and she had a very slightly increased temperature of 38.7degrees. Strangles was discussed as a possibility and we decided to take a sample of pus out of the abscess to test for the bacteria. The skin over the lump was clipped and cleaned to be sterile to avoid any contamination of the sample. A needle was then put into the abscess and the pus that came out was collected onto a swab and sent to the lab.
While we waited for the lab to send us results Roo was isolated from the other horses and her vigilant owner put footbaths and hand washes outside every stable.
The swab came back positive for strangles and Roo was isolated to a field far away from the stable block. Her owner made sure she changed and showered after every visit to see Roo. She checked her other horses for a high temperature twice a day for 21days until the incubation period of the infection was over. She disinfected everything Roo had been in contact with, the stable, tack and brushes included.
Once Roo had been clear of any clinical signs for three weeks we went and performed a guttural pouch wash. We put a small camera up her nose and into her guttural pouches. We put 50ml of sterile saline solution in to wash round the pouch and then took it back out again to send off to see if there was any bacteria left in the guttural pouches. Unfortunately this sample came back positive! Although she had no clinical signs she was still a carrier and was still an infection risk to the other horses on the yard! She continued in isolation for another 3weeks. At this point we went back again to perform another guttural pouch wash. This time, in addition to collecting samples we put penicillin antibiotics into each pouch to make sure, even if this sample came back positive, the existing bacteria in the pouches would be killed.
The second sample came back negative! Roo is now happily back with the other horses on the yard.