Here are some common horse diseases, symptoms, etc:

• Equine Influenza
• African Horse Sickness
• Anticor
• Cerebellar Abiotrophy
• Choke
• Chronic Progressive Lymphedema
• Contagious Equine Metritis
• Covering Sickness
• Eastern Equine Encephalitis Virus
• Epizootic Lymphangitis
• Lethal White Syndrome
• Potomac Horse Fever

There are many more diseases, symptoms, etc, that can be found in a horse. If you would like to find out more, go to wikipedia.com and in the search box type in Equine/Horse Diseases. These are real diseases in horses.