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326 Feline Immunodeficiency Virus Infection

RISK FACTORS various durations (usually many years), and • Useful if cat vaccinated or vaccination history
unknown (can confirm infection if positive)
Free roaming and fighting/biting behavior a terminal phase sometimes called feline • However, false-negatives are common (up
VetBooks.ir CONTAGION AND ZOONOSIS AIDS). Stages are not recognized in natural to 50% false-negative results); test requires
acquired immunodeficiency syndrome (feline
infection.
• Transmissible through saliva and blood, most
meticulous lab conditions to avoid false-
commonly through bite wounds and mating.
Experimentally, also in utero or via milk but • Clinical recovery even in cats in moribund positive results.
condition with severe immunosuppression
uncommon under natural circumstances and secondary infections is possible with TREATMENT
• Environmental contamination is no concern appropriate care.
because virus is infectious only for minutes Treatment Overview
outside the cat and highly sensitive to desic- DIAGNOSIS Lifestyle management is the cornerstone
cation, disinfectants, and heat. of treatment and prevention. Indoor-only
• Not zoonotic Diagnostic Overview lifestyle is highly recommended, to minimize
Usually by detection of FIV-specific antibodies risk of secondary infections. For cats with no
GEOGRAPHY AND SEASONALITY with ELISA or similar tests: clinical signs, no treatment is required. For
Common worldwide, with a higher prevalence • Negative results are highly reliable (in an area cats with secondary infections, comprehensive
in regions with larger numbers of free-roaming with low prevalence); positive results need treatment is required. In FIV-infected cats with
cats (e.g., Italy, Japan, Thailand); prevalence in confirmation because false-positive results gingivostomatitis or neurologic signs, antiviral
the United States ≈2%-3% are possible. treatment can be considered.
• Vaccination-induced and maternal antibodies
ASSOCIATED DISORDERS can interfere with results of some tests. Acute and Chronic Treatment
• FIV infection–induced immunosuppression Treatment in healthy FIV-infected patients
• Increasing susceptibility to chronic secondary Differential Diagnosis • No treatment necessary, but strict indoor-
infections, neoplasia, and stomatitis Other immunosuppressive conditions, such as only lifestyle is strongly suggested (protect
FeLV infection patient and other cats).
Clinical Presentation • Routine ectoparasite control and deworming
DISEASE FORMS/SUBTYPES Initial Database suggested
Clinical presentation in FIV-infected cats Routine laboratory tests: CBC, serum chemistry • Core vaccinations are not recommended for
is rarely caused by FIV itself. Clinical signs panel, urinalysis indoor-only FIV-infected cats.
usually are the result of secondary diseases such • Usually unremarkable in the latent stage; in Treatment if clinical signs present:
as infections or tumors. In most FIV-infected later stages, sometimes lymphopenia (because • Identify and aggressively treat underlying
cats, there are no clinical signs, and the infection FIV replication occurs mainly in lymphocytes diseases (FIV alone is usually not responsible
is an incidental or serendipitous finding. and macrophages) or hyperglobulinemia for the clinical signs).
(because of an immune-mediated response) Treatment of FIV-infected cats with gingivo-
HISTORY, CHIEF COMPLAINT • For exclusion of other (secondary or unre- stomatitis:
• Most commonly discovered incidentally lated) diseases • Glucocorticoids are not recommended.
during routine screening or when evaluating As screening tests of choice, point-of-care ELISA • If concurrent feline calicivirus (FCV) infec-
a cat for other illness or other immunochromatography tests (using a tion, local oromucosal treatment with feline
6
• Clinical manifestations are usually associated similar technique) for detecting FIV antibodies interferon-omega (1 × 10 IU/cat q 24h)
with secondary infections, neoplasia (e.g., in blood • If no FCV infection or interferon-omega not
lymphoma), or FIV-associated neurologic • Presence of FIV antibody considered con- effective, treatment trial with azidothymidine
disorders (rare). sistent with infection because a cat, once (AZT) 5-10 mg/kg PO q 12h plus antibiot-
infected, never clears the infection. ics. In addition, trial with lactoferrin 40 mg/
PHYSICAL EXAM FINDINGS • Two exceptions in which an uninfected cat kg q 24h applied topically to the oral mucosa.
• Commonly unremarkable has antibodies (false-positives): • If insufficient improvement, removal of all
• Gingivostomatitis (most common abnormal- ○ FIV vaccination (some tests, such as SNAP teeth (usually in two sessions; total removal
ity, if any exist) and VetScan, are positive in vaccinated of all tooth roots must be confirmed by
• Findings related to secondary infection or cats; vaccination will cause no interference radiographs)
neoplasia with tests that contain gp40 as the capture Treatment of FIV-infected cats with neurologic
• Rarely, central nervous system (CNS) signs, antigen, such as Anigen and Witness, if signs:
such as behavioral changes, seizures, and vaccination has occurred more than 6 • Identification and treatment of any underly-
paresis months before testing) ing diseases causing the neurologic signs
○ Presence of maternal antibodies (if queen • If no underlying disease identified (and the
Etiology and Pathophysiology is infected or vaccinated) detected up to neurologic signs are assumed to be caused by
• Lentivirus (RNA virus) of the family Retro- 6 months of age FIV directly), treatment with AZT 5-10 mg/
viridae that causes life-long infection with • One exception in which an infected cat has kg PO q 12h
no cure no antibodies (false-negatives): Treatment of FIV-infected cats with recurring
• Several subtypes in different geographic ○ Acute infection (up to 8 weeks are required infections
regions worldwide, based on sequence dif- for antibody production) • Intensive treatment of recurring infections
ferences in the env gene; not differentiated (e.g., long-term antibiotics after culture and
by routine testing Advanced or Confirmatory Testing sensitivity)
• Much less pathogenic than human immu- Western blot (detection of antibodies): • Measure quantitative virus load by reverse
+
nodeficiency virus (HIV) infection or feline • Confirmatory test of choice for antibody transcription PCR (RT-PCR) or CD4
+
leukemia virus (FeLV) infection detection and CD8 cell counts. If virus load is high
+
• Several stages after experimental FIV infec- • Higher sensitivity and specificity than ELISA or CD4 cell counts low, treatment with
tion, similar to HIV infection, including and related tests antivirals (e.g., plerixafor 0.5 mg/kg SQ q
an acute phase (lasting days to weeks), a Polymerase chain reaction (PCR) test (detection 12h or AZT 5-10 mg/kg PO q 12h) should
clinically asymptomatic (latent) phase of of proviral DNA): be considered; treatment has been associated
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