Horses can get the flu, and their symptoms are similar to what people experience: fever, cough, sneezing, runny nose, and watery eyes. Sometimes horses may even have enlarged lymph nodes, stiff limbs, and difficulty breathing. The respiratory diseases seen in the horse are nothing to sneeze at, as they have the potential to lead to serious complications.

Several types of viruses are known to cause the equine influenza, which spreads easily from horse to horse by the droplets discharged during coughing and sneezing. Fortunately, the disease is not usually fatal, except perhaps for the very young, the very old, or for horses with compromised immune systems. But fatal complications, such as pneumonia, can develop if the horse isn't tended to properly or if he is overly stressed by travel and competition.

Horses that routinely come in contact with strange horses are most at risk. If your horse is often exposed to other horses at shows or at a boarding stable that has steady turnover, he definitely needs to be vaccinated against this disease at least once a year, if not more often.

Also called equine rhinopneumonitis, this highly infectious viral disease is caused by a herpes virus. There are two strains, EHV-1 and EHV-4, both of which can cause abortion and respiratory illness in the horse. Obviously, the disease is especially hazardous among pregnant mares, although abortion may not occur until long after the infection has seemingly run its course, and often well into the pregnancy.

Symptoms include mild fever, nasal discharge, and coughing. Young horses are more likely to develop the respiratory form with flu-like symptoms, while older horses may carry the virus but show no signs of illness.

Once you've experienced an outbreak of strangles in your barn, it's not something you ever want to have to deal with again. The disease affects primarily the upper respiratory tract, although it can go systemic. It causes copious globs of cloudy or yellow mucus to stream from the sick horse's nose. The infected nasal secretions can readily spread the disease from horse to horse; however, not every horse exposed will come down with the disease.

Young horses are most susceptible and usually get the sickest. Older horses have had more time to acquire some natural immunity to the disease and often develop a much milder form. These horses may show only minimal nasal discharge and lethargy, symptoms sometimes mistaken for the flu. However, they can still spread the disease through a herd, so if there's any doubt, you should ask your vet to rule out strangles for sure with a test.

Aside from a snotty nose, a horse with strangles exhibits a high fever and depressed attitude. He may also cough, go off his feed, and experience difficulty breathing. Some horses develop abscessed lymph nodes under the jaws in the throatlatch area. The abscesses usually open and drain on their own, or they may need to be lanced by your vet. Otherwise, the swellings can become so enlarged that they actually block the horse's airway, strangling him to death, which is how the disease got its name.

Nursing a horse sick with strangles can be quite labor intensive when there are other healthy horses on the farm that you're trying to protect. You must adopt a workable strategy to prevent spreading the disease to the others. This may involve wearing gloves and sickroom clothes for handling the sick horse and removing them before you get near the others. Each time you exit the sick horse's stall, it's also a good idea to disinfect your shoes by stepping into a kitty litter pan filled with bleach.

After the horse recovers, you'll need to strip his stall down and disinfect it, along with any buckets, lead ropes, halters, grooming utensils, or other items he may have touched. Under the right conditions, the causative bacteria, Streptococcus equi, can linger in the environment and pastures for a period of time after an outbreak.

Also, recovering horses continue to shed the bacteria in their nasal secretions for a short while. Your vet may recommend doing a series of nasal swab tests on your horse every other week or so to determine when he has stopped shedding bacteria and become disease-free. Occasionally, a horse continues to be a silent shedder, or carrier, of the disease, although he has no outward signs of illness.

As a rule of thumb, it is wise to allow no horses to come onto the property or leave (except to go to a veterinary clinic) for about thirty days after the last horse on your farm is declared disease-free. Needless to say, if you run a boarding or riding facility where horses come and go all the time, your business can really suffer during a strangles outbreak. Other horse people will avoid your place like the plague, fearful that they may carry the contagion back to their own farms.

Before the discovery of antibiotics, a significant number of strangles cases were fatal. Nowadays, most horses recover from the disease with treatment; however, some serious complications can develop, even months afterward. One of the more serious systemic complications is purpura hemorrhagica, an inflammation of blood vessels, first evident by sudden and pronounced swelling in the hind legs. This complication is thought to be an autoimmune response, or a type of allergic reaction, to the Streptococcus equi bacteria. A strangles vaccine is available, but it has some risks. For this reason, it's not included in your routine lineup of spring shots unless you and your vet discuss the need for it.