Caused by the bacteria Streptococcus equi equi, strangles is an extremely contagious equine disease. While the majority of horses stricken eventually recover and lead normal lives, the bacteria can stay on a property for a long time. Farms might have to go into quarantine for several weeks, with no equines entering or leaving the premises. While a vaccine is available, it's not that effective.
Any contact with an infected horse's nasal discharge can spread the disease. While it might be relatively easy to avoid nose-to-nose contact, that also means that sharing buckets, water troughs, brushes, tack and other items can potentially spread strangles. Humans in the barn can spread it by petting an infected horse and then touching other equines. Since it can take up to two weeks for an infected horse to show signs of the disease, any new horses on the farm should be kept in isolation for at least that time. That's especially true if a horse arrived from an auction or any place where the health status of other horses isn't known.
Spiking a fever is the initial sign of strangles. A horse's normal temperature ranges from 100 to 102 degrees Fahrenheit. A couple of days after the fever strikes, an affected horse experiences severe nasal discharge and lymph node swelling in the head and neck. The horse appears depressed and lethargic, with little desire to eat. Abscesses form in those swollen lymph nodes. They'll eventually break open, with pus flowing out. The pus can also infect other horses, so use gloves when cleaning out the abscesses and properly dispose of the gunk. Once the abscesses burst, the recovery process usually begins. A small percentage of horses develop complications, especially when the infection goes into parts of the body other than the head and neck lymph nodes. This so-called "bastard" strangles can kill the animal.
Horses suffering from strangles generally need supportive care until the disease has run its course. Most vet will not prescribe antibiotics to fight the infection, as these drugs slow the process of abscess formation. Apply warm compresses to the swellings to encourage the abscesses to rupture. When they do blow out, flush the hole with diluted iodine for a few days until there's no more drainage. Your vet can prescribe non-steroidal anti-inflammatory drugs to ease the horse's pain.
Isolating the Patient
Horses recovering from strangles usually shed the bacteria for up to six weeks. They must be separated from other horses and strict quarantine protocols observed. Barn workers should always feed and water these horses last, after taking care of the healthy stock, washing their hands with antiseptic soap afterwards. In rare cases, a horse might shed the bacteria for as long as 18 months. Your vet can take culture a nasal swab from a recovering horse and let you know when the animal is no longer a bacterial risk.
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