Strangles is a highly contagious disease that produces abscessation of the lymphoid tissue of the upper respiratory tract.
Infected horses become depressed, lose their appetite, develop a 44-106°F fever and a cough. A thick, yellow nasal discharge is present, and lymph nodes of the head and neck swell. Sometimes the lymph nodes swell enough to restrict breathing, which is how the disease got its name. After a week or two the abscessed lymph nodes of the head and throat may rupture and drain.