EIA and Piroplasmosis in Texas

The Texas Animal Health Commission (TAHC) confirmed equine infectious anemia (EIA) in nine racing Quarter Horses located on a Smith County premises on Jan. 31. Subsequently, seven of the EIA-positive horses and one additional horse on the property tested positive for equine piroplasmosis (EP).

The Smith County premises remains in compliance with TAHC rules which require owners to maintain EIA and EP exposed horses in a quarantine zone of no less than 200 yards from unexposed equine and retest exposed animals until cleared.

EIA 101

Equine infectious anemia is a viral disease that attacks horses’ immune systems. The virus is transmitted through the exchange of body fluids from an infected to a uninfected animal, often by blood-feeding insects such as horseflies. It can also be transmitted through the use of blood-contaminated instruments or needles.

A Coggins test screens horses’ blood for antibodies that are indicative of the presence of EIA. Most U.S. states require horses to have proof of a negative Coggins test in order to travel.

EIA and Piroplasmosis in Texas

Once an animal is infected with EIA, it is infected for life and can be a reservoir for the spread of disease. Not all horses show signs of disease, but those that do can exhibit:

  • Progressive condition loss;
  • Muscle weakness;
  • Poor stamina;
  • Fever;
  • Depression; and
  • Anemia.

There is no vaccine and no cure. A horse diagnosed with EIA dies, is euthanized, or must be placed under extremely strict quarantine conditions (at least 200 yards away from unaffected equids) for the rest of his life.

EP 101

Equine piroplasmosis is a parasitic infection of equids that can be spread naturally to equids by ticks or by humans to equids through contaminated needles, syringes, and treatment/surgical equipment and products. The causative agents of the disease are protozoan parasites called Theileria equi and Babesia caballi.

Clinical signs of the disease include fever, anemia (a low red blood cell count), anorexia, depression, swollen abdomens, labored breathing, and jaundice. Some infected animals can carry the disease without showing any clinical signs.

Because state and federal agencies consider EP a foreign disease in the United States, they regulate the management of positive cases. A veterinarian or lab that diagnoses EP must report it to the proper veterinary regulatory authorities. Government veterinarians regulate and supervise quarantine, tick control protocols, and treatment procedures when cases arise.

Owners have if their horses test positive for EP:

  1. Humane euthanasia;
  2. Legal export of the horse to any country that will accept it;
  3. Lifetime quarantine; and
  4. Enrollment in a USDA Animal and Plant Health Inspection Service/USDA–Agricultural Research Service treatment program designed to clear T. equi from the horse while in long-term quarantine.