Feline Leukemia Virus

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What is feline leukemia virus?

Feline leukemia virus (FeLV), a retrovirus, so named because of the way it behaves within infected cells. All retroviruses, including feline immunodeficiency virus (FIV) and human immunodeficiency virus (HIV), produce an enzyme, reverse transcriptase, which permits them to insert copies of their own genetic material into that of the cells they have infected. Although related, FeLV and FIV differ in many ways, including their shape: FeLV is more circular while FIV is elongated. The two viruses are also quite different genetically, and their protein consituents are dissimlar in size and composition. Although many of the diseases caused by FeLV and FIV are similar, the specific ways in which they are caused differs.


How common is the infection?

FeLV-infected cats are found worldwide, but the prevalence of infection varies greatly depending on their age, health, environment, and lifestyle. In the United States, approximately 2 to 3% of all cats are infected with FeLV. Rates rise significantly�13% or more�in cats that are ill, very young, or otherwise at high risk of infection.


How is FeLV spread?

Cats persistently infected with FeLV serve as sources of infection. Virus is shed in very high quantities in saliva and nasal secretions, but also in urine, feces, and milk from infected cats. Cat-to-cat transfer of virus may occur from a bite wound, during mutual grooming, and (though rarely) through the shared use of litter boxes and feeding dishes. Transmission can also take place from an infected mother cat to her kittens, either before they are born or while they are nursing. FeLV doesn't survive long outside a cat's body�probably less than a few hours under normal household conditions.


What cats are at greatest risk of infection? Cats at greatest risk of infection are those that may be exposed to infected cats, either via prolonged close contact or through bite wounds. Such cats include:

Cats living with infected cats or with cats of unknown infection status
Cats allowed outdoors unsupervised, where they may be bitten by an infected cat
Kittens born to infected mothers .Kittens are much more susceptible to infection than are adult cats, and therefore are at the greatest risk of infection if exposed. But accompanying their progression to maturity is an increasing resistance to FeLV infection. For example, the degree of virus exposure sufficient to infect 100% of young kittens will infect only 30% or fewer adults. Nonetheless, even healthy adult cats can become infected if sufficiently exposed.


What does FeLV do to a cat?

Feline leukemia virus adversely affects the cat's body in many ways. It is the most common cause of cancer in cats, it may cause various blood disorders, and it may lead to a state of immune deficiency that hinders the cat's ability to protect itself against other infections. The same bacteria, viruses, protozoa, and fungi that may be found in the everyday environment�where they usually do not affect healthy animals�can cause severe illness in those with weakened immune systems. These secondary infections are responsible for many of the diseases associated with FeLV.


What are the signs of disease caused by FeLV?

During the early stages of infection, it is common for cats to exhibit no signs of disease at all. However, over time�weeks, months, or even years�the cat's health may progressively deteriorate or be characterized by recurrent illness

interspersed with periods of relative health. Signs can include:
Loss of appetite
Slow but progressive weight loss, followed by severe wasting late in the disease process
Poor coat condition
Enlarged lymph nodes
Persistent fever
Pale gums and other mucus membranes
Inflammation of the gums (gingivitis) and mouth (stomatitis)
Infections of the skin, urinary bladder, and upper respiratory tract
Persistent diarrhea
Seizures, behavior changes, and other neurological disorders
A variety of eye conditions
In unspayed female cats, abortion of kittens or other reproductive failures

For rest of article click here: http://www.vet.cornell.edu/fhc/brochures/felv.html


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Feline Immunodeficiency Virus

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What is Feline Immunodeficiency Virus? Virologists classify feline immunodeficiency virus (FIV) as a lentivirus (or "slow virus"). FIV is in the same retrovirus family as feline leukemia virus (FeLV), but the viruses differ in many ways including their shape. FIV is elongated, while FeLV is more circular. The two viruses are also quite different genetically, and the proteins that compose them are dissimilar in size and composition. The specific ways in which they cause disease differ, as well.


How common is the infection? FIV-infected cats are found worldwide, but the prevalence of infection varies greatly. In the United States, approximately 1.5 to 3 percent of healthy cats are infected with FIV. Rates rise significantly-15 percent or more-in cats that are sick or at high risk of infection. Because biting is the most efficient means of viral transmission, free-roaming, aggressive male cats are the most frequently infected, while cats housed exclusively indoors are much less likely to be infected.


How is FIV spread? The primary mode of transmission is through bite wounds. Casual, non-aggressive contact does not appear to be an efficient route of spreading FIV; as a result, cats in households with stable social structures where housemates do not fight are at little risk for acquiring FIV infections. On rare occasions infection is transmitted from an infected mother cat to her kittens, usually during passage through the birth canal or when the newborn kittens ingest infected milk. Sexual contact is not a major means of spreading FIV.
What does FIV do to a cat?

Infected cats may appear normal for years. However, infection eventually leads to a state of immune deficiency that hinders the cat's ability to protect itself against other infections. The same bacteria, viruses, protozoa, and fungi that may be found in the everyday environment--where they usually do not affect healthy animals--can cause severe illness in those with weakened immune systems. These secondary infections are responsible for many of the diseases associated with FIV.


What are the signs of disease caused by FIV?


Early in the course of infection, the virus is carried to nearby lymph nodes, where it reproduces in white blood cells known as T-lymphocytes. The virus then spreads to other lymph nodes throughout the body, resulting in a generalized but usually temporary enlargement of the lymph nodes, often accompanied by fever. This stage of infection may pass unnoticed unless the lymph nodes are greatly enlarged.


An infected cat's health may deteriorate progressively or be characterized by recurrent illness interspersed with periods of relative health. Sometimes not appearing for years after infection, signs of immunodeficiency can appear anywhere throughout the body.
Poor coat condition and persistent fever with a loss of appetite are commonly seen.
Inflammation of the gums (gingivitis) and mouth (stomatitis) and chronic or recurrent infections of the skin, urinary bladder, and upper respiratory tract are often present.
Persistent diarrhea can also be a problem, as can a variety of eye conditions.
Slow but progressive weight loss is common, followed by severe wasting late in the disease process.


Various kinds of cancer and blood diseases are much more common in cats infected with FIV, too.
In unspayed female cats, abortion of kittens or other reproductive failures have been noted.
Some infected cats experience seizures, behavior changes, and other neurological disorders.


Please click here for rest of article : http://www.vet.cornell.edu/fhc/brochures/fiv.html


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