Flashcards in Infectious Dz - Feline Retroviruses and FIP Deck (106)
What type of viruses are retroviruses?
Enveloped RNA viruses
How do retroviruses work?
Their RNA is reverse transcribed into DNA and then integrated into the host's genome
Where is Feline Immunodeficiency Virus (FIV) distributed?
Worldwide - 2.5% prevalence in the US
There are 5 subtypes of FIV. Which subtypes predominate in the US?
Types A and B
How is FIV transmitted?
Mainly through bite wounds, but transplacental transmission is also reported
What are the risk factors for FIV?
Older male, outdoor access, history of fighting, and FeLV infection
What are the phases of FIV infection?
acute, subclinical, and terminal
Characterize the acute phase of FIV.
Viral replication in lymphoid tissue
Decrease in CD4 and CD8 T cells
Mild transient illness - anorexia, fever, and diarrhea
Characterize the subclinical phase of FIV.
Significant drop in viremia
Progressive decrease in CD4/CD8 ratio
Altered immune function
Characterize the terminal phase of FIV.
Susceptibility is opportunistic
Do all cats reach the terminal phase of FIV?
No, some cats may not progress to it
What are the clinical manifestations of FIV?
Gastrointestinal - stomatitis and diarrhea
Neurologic - behavioral changes and locomotor abnormalities
Ocular - anterior uveitis, glaucoma
Neoplasia - Lymphoma and acute leukemia
What is the main problem when you have a patient present for illness and you discover that they have FIV?
You have to determine if FIV was actually the cause of the disease. ALWAYS evaluate for other underlying infections/diseases.
How is FIV diagnosed?
ELISA antibody test
What can cause false positives on the ELISA antibody test for FIV?
FIV vaccinated cats and kittens less than 6 months of age because they could have maternal antibodies
When should you test for FIV?
Test all new cats and then repeat in 60 days
Test all sick cats regardless of prior testing
Test all cats with possible exposure to FIV positive cats and repeat in 60 days
Test all blood donor cats
Test prior to FIV vaccination
Why do you want to retest some cats in 60 days?
Because they may not have developed any antibodies at the time of testing. The 60 day window should give ample time to develop antibodies if they are in fact infected
What should you do if you get a positive FIV result in a patient that is less than 6 months of age?
Retest every 60 days until they reach 6 months of age. If it is still positive at 6 months then consider the patient infected.
What should you do if you get a positive FIV result in a patient that is greater than 6 months of age?
Retest immediately. If positive and not vaccinated, the cat is considered infected.
What should you do with a negative FIV test?
Believe it. The ELISA test is very reliable. If you are suspicious of exposure then retest in 60 days.
What other infectious agents could cause uveitis in patients with FIV?
T. gondii and C. gatti
What other infectious agent could cause the stomatitis in patients with FIV?
For what cats is treatment of FIV reserved for?
Cats in the terminal phase of FIV
What is the treatment for FIV?
Darbepoetin or GM-CSF for cytopenias
Antivirals - AZT and Fozivudine
What should be done for patients that are infected with FIV and asymptomatic?
Prevention should be prioritized. Keep indoors, neuter/spay, do not feed raw foods, and if hospitalized isolate but do not put in infectious disease ward
Is the FIV vaccine recommended?
No. Commercial vaccines are not available anymore. The efficacy is questionable
How long can cats have circulating antibody if given the FIV vaccine?
Up to 4 years
Can cats be vaccinated for other diseases if they have tested positive for FIV?
Yes. Most cats can mount an adequate immune response. Inactivated vaccines should be used.
What is the prognosis for FIV?
Good - multiple studies have shown no difference between mean survival time in positive and negative cats