Equine Infectious Anemia

Question 1

What is Equine infectious Anemia?

Answer 1

• Noncontagious, infectious disease od equidae worldwide.
• retrovirus
  
  • integrated into host’s genomes
• Immune-mediated disease
• Lifelong

Question 2

How is EIA transmitted?

Answer 2

• Via infected blood:
  
  • transplacental transmission
  • fomites - contaminated needles
  • blood feeding insects - mechanical transmission (does not replicate in the insect)

Question 3

What are the 3 forms of EIA?

Answer 3

Acute

Chronic

Inapparent carrier - most frequent

Question 4

What is the acute phase of EIA?

Answer 4

• prolonged period of recurrent febrile episodes, thrombocytopenia, depression, anemia, jaundice, petechiation on mucus membranes, dependent edema, epistaxis, muscle weakness, tachypnea, tachycardia, and weight loss

Question 5

Whatis the chronic phase of EIA?

Answer 5

• Mild - severe disease (1-3days)
• Mild: fever depression, transient inappetence
• Severe: weakness, depression, fever, inappetence, jaundive, tachypnea, tachycardia, vental edema, thrombocytopenia, petechia, death

Question 6

Is there a relationship between clinical signs and amount of EIA virus present?

Answer 6

yes, direct relationship

Question 7

WWhat is the pathogenesis of EIA?

Answer 7

• infection of macrophages and release of pro-inflammatory cytokines
  
  • TNF–a, IL-1, IL-6, TGF-B
  • decreases platelet and RBC production
• Immune mediated destruction of platelets and erythrocytes
  
  • antibody coated platelets and complement coated RBC
  • THrombocytopenia

Question 8

What gross lesions are associated with EIA?

Answer 8

• splenomegaly
• hepatomegaly
• abdominal lymphadenopathy
• pale mucus membranes
• dependent edema
• Mucosal and visceral hemorrhages and thrombosis
• Emaciation in chronic cases

Question 8

What microscopic lesions are associated with EIA?

Answer 8

• nonsuppurative hepatitis, glomerulonephritis, meningitis or encephalitis
• Proliferation of reticuloendothelial cells in many organs (particularly liver), accumulation of hemosiderin in Kupffer cells
• Perivascular lymphocyte accumulation

Question 9

When should EIA be considered as a potential dx?

Answer 9

• horse with:
  
  • eight loss
  • progressive weakness
  • edema
  • anemia
  • fever

Question 10

How is EIA diagnosed?

Answer 10

• Coggins test: agar gel immunodiffusion (AGID)
  
  • internationally accepted serologic test
• ELISA - rapid results
  
  • must be confirmed positive by Coggins
• Samples may only be submitted to state/federal health official or accredited veterinarian - NEED USDA-APPROVED LAB

Question 11

What does a Coggins look for in EIA?

Answer 11

• Antibodies to p26

Question 12

What are the US testing requirements for EIA?

Answer 12

• All equids shipped across state lines must be tested for EIA within 12 mo prior to travel
• All equids sold, traded, or donated within a state must be tested within 12 months prior to change in ownership
• All equids entering horse auctions or sales markets re required to have a negative test before sale
• All equids entered into exhibition or competitions

Question 13

How is EIA controlled?

Answer 13

• No effective treatment or vaccine
  
  • lifelong carriers = usually euthanized
  • Permanent isolation and quarantine of infected horses at least 200 yards from other equids

Question 14

What are the requirements for EIA Seropositive horses in the US?

Answer 14

• Quarantined at least 200 yards from other equids within 24 hours of positive test
• Permanently Identified:
  
  • National uniform tag code number assigned by USDA
    
    • Hot/chemical brand, freezemark, lip tattoo
• Must be removed from herd by euthanasia/slaughter/life-long quarantine
• Must test all horses on premises, and retest at 30-60 day intervals until no new positives,
  
  • quarantine released once negative for 60 days after positive horse removed