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Retroviridae
Feline Leukemia & Sarcoma
Question | Answer |
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Give two reasons why this disease is rarely seen in cats. | (1)The virus is very fragile so unless the cat is CONSTANTLY around infected cats, it will not become infected. (2)Most cats can overcome the primary viremia. |
This virus is associated with neoplastic and nonneoplastic diseases such as... | Anemia, immunosuppression, enteritis, and reproductive failure |
What kind of virus is this? | NONcytopathic and v-onc - |
What is the major FeLV group-specific antigen? Where is produced? Excreted? Found? Detected by? | p27 inner viral core protein. Infected leukocytes and platelets. Saliva and tears. FREE IN THE PLASMA. IFA and ELISA tests |
What protein is responsible for viral attachment? What can the body do to protect against this protein? | gp70 protein. Neutralizing antibodies against gp70 proteins protect against viremia. They are subgroup specific. |
There are 3 main subgroups of FeLV. Which one is found in roughly 50% of naturally infected cats? | FeLV-B and is usually with FeLV-A. |
How is FeLV-B made? | recombinational event between env genes of FeLV-A and endogenous related proviral DNA. |
T/F. Cats infected with FeLV-A & B are at a higher risk of developing tumors than those just with A supgroup. | TRUE |
Which subgroup is the only one that is transmitted horizontally from cat to cat? | FeLV-A |
Which subgroup causes a rapidly fatal nonregenerative anemia and are therefore not transmitted to other cats? | FeLV-C |
How does the FeLV-C version arise? | de novo in a FeLV-A infected cats as a result of mutations in the receptor-binding region of the FeLV-A env gene |
Which envelope protein suppresses lymphocyte blastogenesis by blocking the response of T cells to interleukin 1&2? | p15E. behaves like a cytokine receptor...NOT an attachment site |
FeLV is very liable. What is the difference lifespan of it from dry to wet climates? | Dry: inactivation in 3-5 minutes. Wet: survive for 24-48 hours at room temperature |
If all cats are removed from a FeLV positive house, how long before a new cat can be reintroduced? | 3-4 weeks |
What are three ways the virus can be transmitted? Which one has the highest transmission rate? | Saliva*. Iatrogenic. In utero. |
What 3 types of cells does the FeLV multiply in? | T lymphocytes. B lymphocytes. Myeloid cells. |
Explain the pathogenesis from transmission to a persistent secondary viremia. | Oronasal exposure-Replication in local lymph tissue-low grade(TRANSIENT)viremia-ELISA TEST IS +-Leukocyte and platelet precursors effected in bone marrow-cells released into circulation-presistent SECONDARY viremia-IFA is + |
What is the FOCMA antigen? | Feline Oncornavirus Membrane-associated Antigen. Tumor-specific antigen present only on the membrane of cells transformed by FeLV or FeSV |
What does the FOCMA antibody do? | Lyses tumor cells via ADCC and complement activation so cats with high FOCMA are resistant to leukemia and lymphoma regardless of whether they are + or - for FeLV |
What does the FOCMA antibody NOT do? | Neutralize the virus. Cats can still be viremic and die of nonmalignant diseases |
Within 6 weeks after infection, three types of infection can occur: | Self-limiting. Persisten active. Latent |
Which type of infection do most cats develop? | 92-96% develop the Self-limiting infection and have NO viremia and do NOT shed the virus and develop FOCMA and neutralizing antibodies |
Can you exclude tumors in the future because the cat has a high FOCMA antibody count? | NO...a DNA copy of the FeLV integrates into the host cell DNA |
What two characteristics are present in the Persisten Active infection? What is the killer? | Persistent viremia and Immunosuppression (KILLER) |
What is the deal with the latent infections? | The cat's immune system hasnt' destroyed the virus but it's not overwhelmed by it either.Equilibrium. NO SIGNS and NO SHEDDING. Usually asymptomatic but stresses can cause a persistent viremia |