Properties of Equine Infectious Anemia
 Equine Infectious Anemia (also known as EIA, Swamp Fever or Coggins Disease) is an infectious lentivirus (lenti = slow) of the family Retroviridae that effects members of the Family Equidae. Other lentiviruses include Human Immunodeficiency Virus (HIV), primate lentiviruses, Feline Immunodeficiency Virus (FIV) and Bovine Immunodeficiency Virus (BIV). Retroviruses (and therefore Equine Infectious Anemia) has a simple structure consisting of:
    - a genome
    - a capsid
    - an envelope
    - reverse transcriptase
    - 3 common genes (named env, gag, pol)+ an acquired oncogene (11)

Important things to note about this lentivirus is:
    - The simplest lentivirus genetic organization (11)
 
    - The virion surface contains one single glycoprotein (6)
    - It causes an acute disease rather than slow (7)
    - It is an enveloped virion (easy to inactivate....wash your hands!)


Pathogenesis
The virus enters the horse via biting insects or other infected vehicles (See Transmission). Once the virus has entered the horse, it proceeds as a systemic infection. To get into the tissue, the viral glycoproteins search out different cellular receptors in the host cell. Because it contains an envelope, it can fuse to the host's cell membrane which allows the virion into the cell. Once in the tissue, it will enter macrophages to replicate (8). Because this virus can acquire an oncogene, it is very prone to defects in replication. Even one error in replication can end up in multiple gene mutations of the virus, making it hard for the body to produce sufficient antibodies towards fighting the virus. Viral replication begins with a reverse transcriptase; the transcriptase works by taking the RNA strand of the virus to a double stranded DNA strand. Because equid cells are composed of double stranded DNA, the virus can integrate its own genome into the host's (equid) cell, and then the host will begin to replicate it's DNA with the viral genome integration, resulting in the replication of the virus within the cell. There is a relatively small amount of virus found in the host's tissues, while there is a significant amount of free virus in the blood - which would make sense as the name of the virus includes anemia. (11)