Equine infectious anemia

Equine Infectious Anemia (EIA), also known as swamp fever, is a viral disease affecting horses, mules, and donkeys. The disease is caused by a virus of the family Retroviridae and is transmitted primarily through blood-feeding insects, such as horseflies and deerflies, as well as through the use of contaminated needles, surgical instruments, and during transfusions. EIA is characterized by fever, anemia, jaundice, swelling in the limbs, and occasionally death. There is no cure or vaccine for EIA, making prevention through testing and management practices critical.

Transmission

EIA is transmitted through the exchange of bodily fluids, most commonly blood. The primary vectors are biting insects, which can transfer infected blood from one horse to another. The disease can also spread through the use of contaminated medical equipment or through transfusions of infected blood. Vertical transmission from mare to foal is possible, though less common.

Symptoms

Symptoms of EIA can vary from acute, subacute to chronic, depending on the stage of the disease. Acute cases may present with high fever, severe lethargy, and sudden death. Subacute cases might show moderate symptoms like intermittent fever, weight loss, and anemia. Chronic cases may have mild or no symptoms but can still transmit the virus.

Diagnosis

Diagnosis of EIA is primarily through blood tests, with the Coggins test being the most well-known and widely used. This test detects antibodies to the EIA virus, indicating exposure. Positive horses are often required to be either euthanized or permanently quarantined and branded to prevent the spread of the disease.

Prevention and Control

Prevention focuses on regular testing, controlling insect populations, and practicing good hygiene with medical equipment. Quarantine measures for positive cases are crucial to prevent the spread of EIA. There is no vaccine available for EIA, making management practices the primary means of control.

Legal and Ethical Considerations

The management of EIA involves significant legal and ethical considerations, including mandatory reporting of positive cases, restrictions on movement, and the euthanasia of infected animals in some jurisdictions. These measures, while necessary for public health and the welfare of other horses, raise concerns about the rights of animal owners and the welfare of the animals involved.

See Also

• Horse health
• Viral diseases in animals
• Vector-borne disease