Equine infectious anemia as an AIDS animal model

Abstract

Acquired immunodeficiency syndrome (AIDS) 5.~ is perhaps the most important communicable disease problem in the United States today. 9 Once thought to be a disease of homosexual males and parenteral drug abusers, AIDS is now, in this country, being transmitted increasingly heterosexually to women and to children born to Human Immunodeficiency Virus (HIV) antibody positive mothers, who have contracted the disease. 7,ss Since there is no known cure for the disease, once contracted, HIV infection is persistent and the victim has no assurance of his or her medical future. As of December, 1986, the CDC s reported that over 28,000 cases of AIDS have been reported, including 1,870 women and 394 children under age 13. Heterosexual transmission of HIV infection is becoming more common. In some parts of Africa heterosexual contact apparently is the dominant mode of transmission, particularly in heterosexually promiscuous individuals.45~ Equine infectious anemia virus EIAV is remarkably similar in many aspects to HIV (Table 1). It is most likely that this equine virus can and will be a significant model for the study of the AIDS syndrome and its etiological agent, HIV. The sirnilarities between EIAV and AIDS are many: 1. Mode of transmission: blood 2~ and semen, s4 2. Residence in monocytes where the monocytes become infected with virus and act as an important reservoir for virus 2:6~4~1 and also carry virus to the brain of infected humans. 3. Genomic structure. 1°,~,s2 4. Electron microscopic features) s,s4,~° 5. Pathogenesis based on T-cell targets) 2-34,s° 6. Persistent infection, ls,4~,4z 7. Immunological cross-reactivity of antibody between p26 of EIAV and p24 of HIV 1)9 8. Neurotropism, producing various nervous system diseases) °,23,33,35,37,44,47 However, this aspect of the virus has been limited to a few animals, as most infected horses in the United States are euthanized before neurologic disease may occur. EIAV is a member of the lentivirus group, along with caprine arthritis encephalitis virus, visna virus, u a recently