isoelectric point of 6.5. The protein is prepared in a lyophilized 1 microgram dose. Reconstitution in sterile diluent produces a solution for subcutaneous injection. Approved European treatment Interferon-ω (omega) is sold in Europe at least under the name Virbagen Omega and manufactured by Virbac. When used in treatment of cats infected with FeLV in non-terminal clinical stages (over the age of 9 weeks) there have been substantial improvements in mortality rates; in non-anemic cats, mortality rate of 50% was reduced by approximately 20% following treatment. History FeLV was first described in cats in 1964. The disease was originally associated with leukemia; however, it was later realized that the initial signs are generally anemia and immunosuppression. The first diagnostic test became available in 1973, which led to a "test and elimination" regime, dramatically reducing the number of infected cats in the general population. The first vaccine became available in 1986. Comparison with feline immunodeficiency virus FeLV and feline immunodeficiency virus (FIV) are sometimes mistaken for one another, though the viruses differ in many ways. Although they are both in the same retroviral subfamily (Orthoretrovirinae), they are classified in different genera (FeLV is a gamma-retrovirus and FIV is a lentivirus like HIV-1). Their shapes are quite different: FeLV is more circular while FIV is elongated. The two viruses are also quite different genetically, and their protein coats differ in size and composition. Although many of the diseases caused by FeLV and FIV are similar, the specific ways in which they are caused also differ. Also, while the feline leukemia virus may cause symptomatic illness in an infected cat, an FIV infected cat can remain completely asymptomatic its entire lifetime. See also Feline foamy virus (FFV) Feline immunodeficiency virus (FIV) Feline vaccination References B. Zharkoy, A. Zolototrubov, D. Fedosov. "Intensity of free radical processes in limphocytes at BLV and FeLV". Journal of Animal Science. XLII,5/2005, p. 272-276. External links Lymphocyte T-Cell Immunomodulator (LTCI) Feline Leukemia Virus (FeLV) from Veterinary Partner Feline leukemia Treatments and Support Feline Leukemia Virus from Cornell Feline Health Center Feline Leukemia Virus Infection (FeLV) in Cats Feline leukemia virus inhibits thiamine uptake, with pathological consequences Cat diseases Gammaretroviruses Animal viral diseases