Feline Leukemia Virus (FeLV) ✪ FeLV is distributed worldwide. The domestic cat is the predominant host, but the virus can also infect other felidae. Navies 2011. Etiology. FeLV retrovirus in family Oncoviae Subgroups Subgroup A: All infected cats have this type, causes immune suppression
Feline Leukemia Virus (FeLV)✪FeLV is distributed worldwide. The domestic cat is the predominant host, but the virus can also infect other felidae
The feline leukemia virus (FeLV) was discovered in 1964 in a cluster of cats with lymphosarcoma. The observed clustering of cases of feline lymphosarcoma suggested that FeLV was an infectious agent for cats. The development of a simple immunofluorescent test for FeLV permitted a seroepidemiological study to be undertaken on the distribution of the virus in cats living in their natural environment. Over 2000 cats were tested, and the results showed conclusively that FeLV is an infectious agent for cats.
Males are 1.7x more likely to be infected
1-6 years of Age
that it cannot be
passed on to other
species. Cats only.
Incidence is directly related to the population
Healthy cats can transmit this virus, they can be a carrier
Large quantities are secreted through saliva
Tears, urine , & feces (less likely but still possible)
Vertically & Horizontally
Virus is unstable within the environment close contact must occur for infection to take place
Incubation Period: about 8 weeks
Some strains of FeLV can be grown in human tissue cultures. This has led to concerns of possible transmission to humans. Several studies have addressed this concern; none have shown any evidence that any zoonotic risk exists
★ Anisocoria is occasional within FeLV patients
“Secondary infections”: non healing
Vomiting & diarrhea
Tumors of lymphoid origin
IFA (Immuno Florescence Assay)
Tests for the presence of structural antigens in the cytoplasm of infected cells
Tests for the presence of FeLV p27
Tests for antigens vs. virus itself
Accuracy is higher when both tests are run
There are 6 stages of FeLV infection as follows:
Stages 1-3 - FeLV is disseminated through the lymphoid tissue.
Stage 4 – FeLV infects the bone marrow.
Stage 5 - Viral-infected neutrophils and platelets are released from the bone marrow.
Stage 6 – FeLV appears in epithelial tissues (e.g., salivary glandular epithelium).
Broad Spectrum Antibiotics
Elimination of stress
★These drugs are toxic to bone marrow.
Cats should have hemograms reevaluated
frequently during treatment. Limit
treatment to 3-week intervals to avoid
Depends on immune status, exposure to virus, & vaccination history
70% develop immunity & are able to fight of the virus before developing the symptoms
30% that’s don’t develop the immunity are persistently viremic
Stress, or drugs that suppress the immune system, can develop a viremic breakout
IFA positive =will succumb within 6 months of detection
Average lifespan is less than 3 years
★The virus causes both immune cell depletion and dysfunction which result in several FeLV-induced
immunopathologic diseases and numerous secondary immunosuppressive diseases which together are
the major cause of death of FeLV-infected cats
Persistently veremic cats may manifest single or multiple neoplastic diseases:
Lymphoma (Most Common)
Thymic lymphoma (usually in young cats <3 years old)
Erythroid and Myeloid Leukemias
Infertility, Fetal Resorption or Abortion
Pathologic Lesions (Examples)