FeLV: Feline Leukemia Virus

• FeLV stands for Feline Leukemia Virus
• FIPV stands for Feline Infectious Peritonitis

FeLV: Feline Leukemia Virus

• FeLV is an RNA retrovirus, specifically a gammaretrovirus

• FeLV is a virus, not a cancer itself

• The virus is associated with both neoplastic and non-neoplastic diseases

• FeLV is the most common cause of cancer in cats

• Parts of the feline retrovirus can be incorporated into a cat's DNA, called "endogenous" enFeLV DNA

• This enFeLV is not complete and cannot replicate on its own

• There are four subgroups of FeLV: FeLV-A, FeLV-B, FeLV-C, and FeLV-T

• The FeLV virus is very unstable in the environment

• Transmission of FeLV requires close contact between cats

• The FeLV virus may be isolated from saliva, nasal secretions, urine, feces, tears, and milk

• Transmission can occur through grooming, fomites, and fighting

• Transplacental and transmammary transmission is possible

• FeLV can produce a wide variety of associated diseases and symptoms:

  • Immunodeficiency
  • Anemia
  • Reproductive problems
  • Gastrointestinal problems
  • Neurological problems
  • Lymphadenopathy
  • Cancer
  • Respiratory and eye problems
  • Oral problems

• Outcome after a cat is exposed to the virus depends on many host factors

• The immune system is integral in determining the final outcome after exposure

• Exposed cats may develop a regressive infection (transient)

• Exposed cats may develop a progressive infection (persistent viremia) with no clinical signs

• Exposed cats may develop an active infection with clinical signs

• Outcome depends on cat's immune status

• Viremia is evident 2-4 weeks after infection

• In early stages, there may be no clinical signs

• Over time, a cat's health may progressively deteriorate, or be recurrent with periods of relative health

FeLV Clinical Signs

• Mild fever
• Loss of appetite
• Progressive weight loss
• Poor coat condition
• Enlarged lymph nodes
• Pale gums or mucous membranes (MM)
• Persistent gingivitis
• Diarrhea
• Secondary infections
• Behavior changes
• Neurological signs such as seizures
• Reproductive failure

FeLV Diagnosis

• Diagnosis can be achieved through a positive ELISA test
• SNAP tests can be used for diagnosis
• Positive IFA test
• Diagnosis based on clinical signs of recurring infection

FeLV Diagnostic Tests

• ELISA detects the primary viremia, before the bone marrow becomes infected

• IFA test detects circulating viruses primarily during the second stage

• With ELISA, the cat may still ward off the virus

• IFA results are positive for life

• A negative FeLV test does not imply immunity or non-exposure

• A negative FeLV test may result if the cat has never been exposed to FeLV

• A negative FeLV test may result if the cat is incubating the virus at an earlier stage

• A negative FeLV test may result if the cat overcomes a previous infection and has not become persistently viremic or regressive

• A negative FeLV test may result if the cat has been infected with the virus and has developed the disease

FeLV Treatment and Prevention

• Treatment is supportive
• Ensure minimal susceptibility to other illnesses
• Prevention primarily involves vaccination -Vavccination does not interfere with either test

FeLV Positive Cats

• A healthy FeLV-positive cat need not be euthanized

• Keep the animal indoors

• Isolate from all other cats

• Keep up with vaccinations

• See a veterinarian if any signs of disease develop

• PureVax Recombinant FeLV: Manufactured by Boehringer Ingelheim

• Administered subcutaneously

FIV: Feline Immunodeficiency Virus

• Feline Immunodeficiency Virus (FIV) attacks the immune system
• Infected cats with an immune response will develop antibodies against the virus that persist for their life
• FIV is a retrovirus of the lentivirus type
• Morphologically and biochemically similar to HIV but antigenically distinct
• Cats most at risk are those that participate in fighting
• Transmission occurs through fighting and bite wounds
• Neonates become infected by contact with queens
• After initial infection, the FIV virus is carried to regional lymph nodes where it replicates in the T-lymphocytes
• Spreads from there. Lymph nodes around the body, enlarged
• Infected cats can appear normal for years
• Then will develop immune deficiency
• There are three phases of the virus in cats: Acute, latent, and progressive

FIV Phases

• Phase 1 Acute: virus carried to lymph nodes, replicates, spreads to other lymph nodes in the body, which causes enlargement, fever, depression, lack of appetite
• Phase 2 Latent or asymptomactic: lasts months or years, blood work abnormalities
• Phase 3 Progressive: immunocompromised, secondary infections occur

FIV: Clinical Signs

• Persistent fever

• Anorexia

• Gingivitis (common)

• Stomatitis (common)

• Cachexia

• Vomiting and diarrhea (V&D)

• Recurrent/chronic infections (skin, bladder, upper respiratory) Diagnosis of FIV: Clinical signs, history, FIV antibody test (ELISA), and PCR tests FIV testing: Depends on the host cat mounting an immune response to the virus

• Host cat has not had sufficient time after exposure,

• Or host cannot mount an immune response.

• Antibodies may not be detectable in a cat actually infected with FIV

FIV Treatment

• Keep infected cats indoors
• Isolate if aggressive to other cats in household
• Transmission from fomites or casual contact is unlikely

FIPV: Feline Infectious Peritonitis

• Caused by a coronavirus, a mutated strain known as feline enteric coronavirus (FECV)
• Many different coronaviruses capable of infecting cats, but do not produce serious illness
• FIPV is a cat that was infected with a FECV and the virus has mutated
• Occurs in 10% of cats infected with a feline enteric coronavirus
• Unique ability to invade and grow in certain white blood cells.
• WBC then transmits throughout the cats body
• WBC then locates an inflammatory reaction
• It interaction between body's immune system and the virus that is responsible for the disease

FIPV Transmission

• Infected cats shed the coronavirus in their saliva and feces
• Can be spread by direc contact and/or fomites
• The virus is more table than FeLV but only survives for a few weeks in environment

FIPV Distinct Forms

• Wet (Effusive) 75%

  • Perivasculitis results with protein rich fluid
  • Thoracic/Abdominal/Scrotal/Pericardial/Renal/ Subcapsular

• Clinical Signs: Ascites, pleural effusion, Anorexia, depression, weight loss, dehydration, febrile, swollen lymph nodes

• Dry (Non-Effusive)

  • The clinical signs are vague
  • pyogranulomatous lesions occur
  • Clinical Signs: Fever, Anorexia, Depression, Weight loss, Ocular lesions (uveitis), Neurologic lesions, enlarged kidneys (rare)

FIPV testing and diagnosis

• Hematology: Globulins, Lymphopenia, Hyperbilirubinemia, Hyperglonulinemia, Albumin , Mild-moderate anemia, RBC microcytosis, Band neutrophilia
• Susceptibility: Young cats < 2 years old and older cats >10 years of age
• FIPV: Cats in poor physical condition and/or with concurrent infections or stress A Presumptive diagnosis = based on clinical signs, laboratory tests, Elisa/IFA/PCR, Evaluation of fluid, laboratory tests
• Definitive diagnosis= Biopsy (immunohistochemical detection = Gold Standard): Inflammation

Rivalta Test

• Assay of the inflammatory protein content of the fluid sample
• Test tube is filled with 7-8ml distilled water, add drop drop of glacial acetic acid
• Drops of effusion are placed on top of the solution and observe
• Drop of effusion retains its shape and slowly drifts to the bottom of the tube the test is posive
• Negative test, the drop dissolved and tube appears cleaer

FIP Treatment

• Is routinely fatal
• Supportive care
• Alleviate destroying inflammatory response of the disease
• GC376+GS441524= Coronaviral protease inhibitor and analog
• Feline FIP by Zoetis: temp sensitive mlv
• Intranasal admin
• Cats over 16 weeks
• 2 doses, 3-4 weeks apart