Feline Leukemia Virus (FeLV)

By: Michelle Young

All About FeLV

•Feline leukemia virus (FeLV), is a retrovirus.

•Retroviruses produce an enzyme, which permits them to insert copies of their own genetic material into that of the cells they have infected.

•FeLV-infects cats worldwide, but the prevalence of infection varies greatly depending on their age, health, environment, and lifestyle.

•In the US, approximately 2 to 3% of all cats are infected with FeLV.

How FeLV spreads

•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 from mother to kittens.

•Transfer of virus may occur from a bite wound, and through the shared use of litter boxes and dishes.

•However, the virus doesn’t live long in the environment, only a few hours under normal household conditions.

What cats are at risk of infection?

• Cats that are exposed to other infected cats; through bite wounds or other close contact.

• Kittens are much more susceptible to infection than are adult cats, and therefore are at the greatest risk of infection if exposed.

What problems can FeLV cause? 

• Most common cause of cancer in cats

• Can cause various blood disorders

• Lowers the cat’s immune system so that it becomes susceptible to other diseases.

• Bacteria and viruses that are found in the normal everyday environment can cause severe illness in those with weakened immune systems.

• The secondary infections are responsible for many of the diseases associated with FeLV.

SymptomsDuring the early stages there may be no signs of disease. Over time, the cat’s health may progressively deteriorate or the cat may have recurrent illnesses.

•Loss of appetite & weight loss that is slow in the initial stages of the disease but can become more late in the disease process

•Poor coat condition

•Enlarged lymph nodes

•Fever that doesn’t go away

•Pale or inflamed gums

•Skin Infections, abscesses

•Urinary and upper respiratory infections

•Persistent diarrhea

•Seizures or other neurological problems

•Problems with the eyes

Two Stages of Infection

•Primary viremia- the early stage of infection. Some cats may have an effective immune response & will be able to eliminate it from the bloodstream

•Secondary viremia- later stage marked by persistent infection of the bone marrow & other tissue. If the infection gets to this stage, most cats will be infected for the rest of their lives.

Testing for FeLV

• Two types of FeLV blood tests are in common. Both detect a protein component of the virus as it circulates in the bloodstream.

• ELISA -detects both primary and secondary stages of viremia. Can be performed in vet’s office.

• IFA - test must be sent to diagnostic lab. IFA tests detect secondary viremia only

How to protect cats from FeLV

• The only sure way to protect cats is to prevent their exposure to FeLV-infected cats

• Keep cats indoors

• Keep uninfected cats separate from infected cats; don’t allow infected cats to share food bowls or litter boxes with uninfected cats

• Consider FeLV vaccination of uninfected cats. However, the vaccine isn’t 100% effective

How to care for infected cats? 

• Confine FeLV-infected cats indoors to reduce their exposure to other infectious agents carried by animals and to prevent the spread of infection to other cats

• Spay or neuter infected cats

• Feed well balanced, healthy diet

• Avoid raw feeding due to increased risk of bacterial or parasitic infection

How long can an infected cat live?

•Infected cats may remain in good health for many months

•Most cats die from an FeLV-related disease within two or three years.

•If a cat has already experienced one or more severe illnesses as a result of FeLV infection a much shorter survival time can be expected.

References

Feline Leukemia Virus

http://www.vet.cornell.edu/fhc/brochures/felv.html

Facts about Feline Leukemia Virus

http://armv.org/adoption/facts-about-feline-leukemia-virus/

Feline Leukemia Virus or FeLV in Cats 

http://www.medicinenet.com/pets/cat-health/feline_leukemia_virus_or_felv_in_cats-page2.htm