Horses are subject to a variety of diseases and conditions. Among the most common are diseases that are transmitted by bites from ticks and from mosquitoes. Diseases that are caused by bacteria are common in horses and there are other frequently seen ailments that are brought about by viruses. Horse diseases come with numerous symptoms, ranging from such mundane side effects as diarrhea to more serious symptoms such as loss of muscle control.
Cushing's disease is a common ailment that attacks the endocrine system of the animal. It is an incurable condition but it can be managed in most instances with proper medication. The result of a problem that affects the pituitary gland, Cushing's disease makes the pituitary manufacture excess amounts of a hormone known as cortisol. This hormone regulates a number of functions in the horse and the over-production of it can bring symptoms such as a thick wavy coat, thirst and an uncommon appetite, loss of weight even though the horse eats well, and frequent urination. Cushing's occurs for the most part in older horses but since many of the symptoms of the malady are attributed to aging a diagnosis is often not made until the horse has suffered from Cushing's for some time.
Tetanus is a dangerous infection that is caused by bacteria entering a wound in a horse. It can also be passed to a foal from its mother through the umbilical cord. The early signs of this disease are colic and rigidity in the muscles, with horses having spasms in the neck, hind legs, jaw, and the region close by to the wound where the bacteria first gained access. Tetanus will eventually kill a horse through respiratory paralysis if it is left untreated. But if the wound is cleaned and all the tissue in the infected area is removed, then antibiotics should control the infection.
Mosquito bites can infect horses with a viral disease known as encephalitis, which commonly comes in three forms. Eastern, Western and Venezuelan Equine Encephalitis each will attack a horse's central nervous system. High fever that lasts for a span of two to three days is the initial sign of this horse disease. The brain of the animal becomes inflamed over time, with the horse losing coordination, muscle control and becoming terribly sluggish. The final phases of encephalitis bring seizures and paralysis. The eastern version of the disease is the most dangerous, with mortality rates as high as 90 percent. Treatments for encephalitis in a horse once they have the disease, which mosquitoes transmit from birds they have bitten, is limited. The best way to protect a horse is with a vaccination against this disease by a licensed veterinarian.
West Nile Virus
West Nile Virus is another mosquito-caused viral illness in horses that is spread when a mosquito bites an infected bird and then transmits the ailment to a horse through its bite. West Nile Virus results in encephalitis along with possible meningitis, which is a swelling of the lining of the spinal cord and the brain. Trembling muscles, poor coordination, and lethargy are signs of this disease. Horses can be vaccinated against West Nile Virus, unlike humans who are also vulnerable to this illness.
Diseases Caused by Ticks
Tick bites are responsible for transmitting many diseases to horses. Lyme disease is bacterial in nature and slowly brings about such symptoms as arthritis and pain in a horse. Antibiotics can help the horse but it may take as long as two whole years. Equine ehrlichiosis is a tick-borne illness in which tiny microorganisms give a horse a fever and make them lose their appetite, but antibiotic treatment can cure the horse when the disease is diagnosed. Extreme anemia is the result of equine piroplasmosis while Colorado tick fever is a severe viral infection; both are common horse diseases precipitated by a tick bite.
Other Common Diseases
Equine influenza affects the upper respiratory system of a horse with symptoms such as a fever, a cough and a lack of appetite. Potomac horse fever causes diarrhea in horses, with the vast majority of cases occurring in the eastern portion of the United States. Strangles is a horse disease that is very contagious among horses. It can cause the animal's lymph nodes to swell in the region of the jaw. Horses under the age of two can catch equine herpes virus, a disease which makes horses cough and have a discharge through the nose.