Dr. Thomas Lenz writing in The American Quarter Horse Journal reminds horse owners that up-to-date testing of horses for equine infectious anemia (EIA) is important because of the potential devastation of the horse population by the disease.
Importance of testing for horse diseases
EIA infected horses may die from direct effects of the virus or from secondary infections, and often horses have to be euthanized because of the effects of the disease.
EIA infected horses may die from direct effects of the virus or from secondary infections, and often horses have to be euthanized because of the effects of the disease.
According to Dr. Lenz, "Some owners consider testing for equine infectious anemia a nuisance and an unnecessary expense. Testing is done via a blood test commonly called a Coggins test.
EIA is spread when horseflies and deerflies bite a horse that is infected, and then carry the infection on to other horses they bite. EIA can also be transmitted by using the same needle on multiple horses, contaminated surgical or dental instruments and body fluids such as milk, urine or saliva.
The disease can only be transmitted to Equidae (horses, donkeys, mules, zebras, etc.), not humans. Approximately 5 percent of horses who contract EIA develop acute clinical symptoms, which include high fever (105 to 107 degrees F), depression and anemia and usually die within two to three weeks.
The symptoms of acute EIA resemble those of anthrax, influenza or encephalitis and therefore are seldom diagnosed in acute cases until after the horse’s death.
The blood of acutely infected horses contains high numbers of virus particles, and so the affected horses are extremely contagious. An estimated 95 percent of EIA-infected horses do not develop acute symptoms, but rather become chronically infected.
The chronically infected horse might appear completely healthy, but act as a reservoir of the disease his entire life. However, the carriers might become acute and begin shedding due to severe stress, hard work or the presence of other diseases. Other chronically infected horses might become “poor doers” that lose weight, become lethargic, often develop edema (swelling) under their chest and lower legs, and periodically run a fever.
There is no vaccine or effective treatment for EIA.
To reduce the risk of horses contracting EIA, all horses need to be tested to ensure that they are not positive. Before allowing outside horses on their premises, all horse owners should require a negative Coggins test.
Disposable syringes and needles should be used when treating or vaccinating horses and the same needle should never be used on multiple horses.
Since the disease is spread by biting insects, effective insect-control measures need to be taken and new equine arrivals should be quarantined for at least 30 days.