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Equine Infectious Anemia (EIA)

What is Equine Infectious Anemia (EIA)?

Equine Infectious Anemia (EIA) is a viral disease affecting only members of the equidae family (horses, ponies, zebras, mules, and donkeys). There is no vaccine or treatment for the disease. Infection is often in-apparent and results in a lifelong carrier state if the horse survives the acute phase of the infection. EIA is found widely throughout the world. There is no evidence that EIA is a threat to human health. EIA is a reportable animal disease in all states.

The clinical signs are often nonspecific and of variable severity. Clinical signs in an acute case can range from fever and decreased appetite to severe anemia and sudden death. It is often difficult to differentiate EIA from other diseases.  Incubation period is a week to 60 days or longer.  Additional clinical signs in an acute case can include:

  • Jaundice (yellow discoloration of mucous membranes)
  • rapid breathing, rapid heart rate
  • swelling of limbs
  • bleeding from the nose, or red/purple spots on mucous membranes
  • blood-stained feces

Horses that survive the acute phase of the disease become chronic, in-apparent carriers.  Some carriers may develop recurrent flare-ups, often following another stress – illness or strenuous work. While donkeys and mules have the ability to contract this virus, most remain non-clinical.

*For further information, documents and references please open the EIA Documents and references tab

Samples to collect

  • Serum should be collected and submitted to an EIA APHIS-Approved Laboratory using a VS Form 10-11 or another VS approved EIA form, alternatively, you may submit electronically via VSPS (https://vsapps.aphis.usda.gov/vsps/) - which is free for veterinarians and laboratories to use - or another, VS approved, electronic EIA submission system.

    For questions, or supplies of paper VS 10-11s, please contact your APHIS-VS District office 

  • VS 10-11 Instructions (2020).  Note that VS 10-11 forms are only available to accredited veterinarians and there are no approved fillable pdfs of the form for submissions. 

Post Mortem Lesions

  • Spleen, liver and abdominal lymph nodes may be enlarged. Mucous membranes can be pale. In chronic cases, emaciation may also be noted. However horses that die between clinical episodes may have no gross lesions.

*For further information, documents and references please open the EIA Documents and references tab.

Natural transmission of EIA is by blood feeding flies (horse flies and deer flies) and is limited to relatively short distances. This virus is frequently transmitted via unclean or re-used needles and syringes, blood transfusions and contaminated instruments (IV sets, dental instruments, tattoo equipment).  Mares can transmit the virus to foals in utero, and, less likely, transmission can occur via milk or semen.

*For further information, documents and references please open the EIA Documents and references tab

There is no treatment for EIA. Because infected animals become lifelong carriers they must be permanently isolated and quarantined or euthanized.

*For further information, documents and references please open the EIA Documents and references tab

Reducing exposure to biting flies through management practices may reduce the spread of infection. To prevent iatrogenic spread, never reuse needles, syringes or IV sets, use only new, clean needles with injectable medicines and use only licensed and approved blood products. Blood transfusions should be performed only by licensed veterinarians using donor horses tested negative for EIA and other blood-borne infections like equine piroplasmosis.

Surveillance and testing are the best methods of prevention. Since EIA control efforts began over 40 years ago the reactor rate has fallen from 4% to .004% in 2017 among tested animals. USDA recommends testing every equid annually.

There is no vaccine approved for use in the U.S.

*For further information, documents and references please open the EIA Documents and references tab

  1. Call your veterinarian
  2. Move suspected horse at least 200 yards away from other horses
  3. Reduce exposure to biting flies

*For further information, documents and references please open the EIA Documents and references tab.

Annual total number of equine cases of EIA and number of affected premises in each State, 2001 - 2019.

2019
89 positive horses, 38 positive premises



2018
51 positive horses, 33 positive premises



2017
80 positive horses, 38 positive premises



2016
52 positive horses, 34 positive premises



2015
65 positive horses, 32 positive premises



2014
49 positive horses, 25 positive premises


 


2013
38 positive horses, 23 positive premises


2012
36 positive horses, 27 positive premises

 


2011
82 positive horses, 30 positive premises

map 2011 eia positive states


2010
49 positive horses, 32 positive premises 


2010 eia distribution map


2009
37 positive horses, 30 positive premises 

Map of 2009 EIA reactors and premises


2008
113 positive horses, 84 positive premises 

Map of 2008 EIA reactors and premises


2007
120 positive horses, 70 positive premises 

2007 - Equine Infectious Anemia Cases and Premises


2006
188 positive horses, 83 positive premises 

2006 - Equine Infectious Anemia Cases and Premises


2005
183 positive horses, 145 positive premises 

2005 - Equine Infectious Anemia Cases and Premises


2004
338 positive EIA tests
Map - 2004 Equine Infectious Anemia Cases


2003
273 positive EIA tests
Map - 2003 Equine Infectious Anemia Cases


2002
424 positive EIA tests

Map - 2002 Equine Infectious Anemia Cases


2001
534 positive EIA tests
Map - 2001 Equine Infectious Anemia Cases

 

 


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