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Newsletter
Issue 1 Feline Leukemia and FelineImmunodeficiency Virus Felv(feline leukemia virus) and FIV(feline immunodeficiency virus) infection may cause similar disease syndromes. They are however very different in their respective prevalence rates and very rarely occur together in the same cat or groups of cats. Felv is an oncornavirus (cancer causing RNA virus) that is capable of infecting and causing diseases of blood cells and immune defense system in the persistently infected cat. Infection requires repeated exposure, usually through close contact, licking and grooming, as saliva is the most common vehicle of the virus. Initially, very mild cold or flu like symptoms are seen and approximately 70% of exposed cats will neutralize the virus within two to three weeks. These cats will be free of the life threatening effects of acute infection but may have changes in their genetic structure which cause related but non active virus induced cancer later in life. Felv actually causes changes in the cats genes by insertion of inactive provirus genetic material even in the cat that effectively overcomes the active initial infection. This viral related genetic material may act to promote the cat's own species specific oncogenes with time and natural random or hypothesized regular DNA mutations. The 30% that have established virus infection will generally within 3-5 years develop either severe anemia, infection or overt cancer depending on the strain of virus and age of the cat. Anemia is certainly the most commonly seen symptom in the young to middle aged cat while true leukemia or cancer of the blood and lymph nodes is most common in the very young kitten and adolescent cat. Groups of cats may harbor endemic infection and in these situations repeated exposure may result in the establishment of persistent infection in the previously exposed "resistant" individual cat presumably due to waxing and waning levels of protective antibodies. FIV infection is very different in its initiation and course of disease. Fighting and biting with direct inoculation of the virus is the most common route of infection. Little surprise that the most common symptomatic cats are intact males or very aggressive females that roam the night. Similar to human immunodeficiency virus this virus true to its name (Leant or slow RNA virus) may not cause disease for 5-l0 years depending on the cats inherent resistance. Infection, anemia and non specific wasting syndromes are most common but cancer may also be seen. Although most identified cats with active disease and infection have been males, the female is not specifically immune to this disease and it really depends on the risk of exposure to fighting with infected asymptomatic cats. For example we have noticed frequent infection of feral cats that inhabit a nearby local fairgrounds area. Concurrent Felv infection is not common in this population. In our next issue we will discuss diagnostic testing, prevention (including vaccination procedures with Felv) and treatment protocols that are currently advocated for these two virus diseases. |