Young horses one to three years of age are at increased risk of contracting strangles. Large boarding or training facilities are at higher risk due to the higher amount of people entering and exiting the barns. The incubation period for strangles is three to six days, after which the clinical signs and symptoms include fever up to 41.1 ºC, anorexia, lethargy, pain, dry cough, lymphangitis, pharyngitis, nasal discharge, lacrimal discharge, and of the mandibular, pharyngeal and parotid lymph nodes that may rupture and form a drainage tract. This can also result in dysphagia, dyspnea or apnea & possible death due to asphyxiation. Diagnosis of strangles is made through clinical signs and symptoms, nasal swab and bacterial culture from the pus. hydrotherapy over the site of abscesses to encourage the external rupture of the abscesses, surgical drainage of the abscesses, supportive care and systemic antibiotics. Treatment includes isolation, the application of Prognosis for strangles is good with prompt treatment, while the prognosis for bastard strangles is guarded.
Prevention is through vaccine and strict quarantine measures.
Laryngeal Hemiplasia
Laryngeal hemiplasia is caused by a progressive anteriograde degeneration of the large myelinated axon of the recurrent laryngeal nerve. It is often a congenital idiopathic or iatrogenic condition. This causes neurogenic atrophy of the intrinsic laryngeal muscles, especially the dorsal cricoarytenoideus muscle. This muscle normally controls the cartilages and the vocal folds. If this muscle is paralyzed the vocal fold prolapses into the lumen of the airway, reducing the diameter of the airway. A reduction in airway diameter causes the horse to work harder to achieve normal ventilation of the lungs. As air is forced through the larynx it causes the prolapsed vocal fold to vibrate, making a whistling or roaring noise on inspiration. Laryngeal hemiplasia most commonly occurs in long necked, large body horses. It is reported that idiopathic laryngeal hemiplasia occurs more commonly in males than in females. It is also reported that hemiplasia occurs more commonly on the side than the right. It can be caused by the intramuscular injection of irritating substances into the left side of the neck. The left recurrent laryngeal nerve is slightly longer and more superficial then the right making it more susceptible to injury. Laryngeal hemiplasia is seen clinically as inspiratory stridor during exercise and exercise intolerance. Most horses are asymptomatic at rest.
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