Anemia, Equine Infectious

Anemia, Equine Infectious



Basic Information image



Definition


Equine infectious anemia (EIA) A viral infection of Equids caused by a lentivirus and characterized by inapparent infections and occasional clinical disease with recurrent episodes of fever, lethargy, inappetence, thrombocytopenia, and anemia



Synonym(s)




• Swamp fever


• Coggins disease


• EIA



Epidemiology



Species, Age, Sex




• No known age, gender, or breed predisposition


• Affects horses, ponies, donkeys, mules, and zebras



Contagion and Zoonosis




• Spread by transfer of blood or body fluids


image Most commonly transmitted by large biting horseflies and deerflies.

image Stable flies may also be involved in transmission.

image Insects are mechanical vectors, and the virus lives only a limited amount of time on vector mouthparts.

image Iatrogenic infections are common through use of common needles or contaminated equipment.

image A recent outbreak in Ireland suggests the possibility of direct or indirect horse-to-horse transmission without vectors or iatrogenic infection.

• Not zoonotic



Geography and Seasonality




• Present worldwide


• Prevalence highest in regions with warm climates and large numbers of potential vector insects


• In the United States, most common in Gulf Coast states



Clinical Presentation



Disease Forms/Subtypes




• Acute disease causes fever, lethargy, and inappetence with mild thrombocytopenia.


• Inapparent infection with no recognizable clinical signs is most common.


• Chronic disease is associated with recurrent episodes of fever with weight loss, ventral edema, and petechial hemorrhages.



History, Chief Complaint




• Fever, weight loss, petechial hemorrhages


• Inapparent carriers often identified at time of routine surveillance testing



Physical Exam Findings




• Acute disease: Fever, lethargy


• Inapparent carrier: Minimal recognizable clinical signs


• Chronic disease: Fever, ventral nonpainful pitting edema, petechial hemorrhages, poor body condition



Etiology and Pathophysiology




• EIA virus is a member of the lentivirus genus of the Retroviridae family.


• Establishes persistent, lifelong infection in Equids.


• The virus undergoes antigenic variation with resultant recurring episodes of fever and viremia.


• The immune system ultimately controls viral replication in most horses, resulting in inapparent carriers with minimal signs of disease.


• Uncontrolled viral replication results in signs of chronic disease.


• Anemia and thrombocytopenia probably result from immune- and non–immune-mediated peripheral destruction of erythrocytes and platelets as well as impaired bone marrow production of new cells.

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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on Anemia, Equine Infectious

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