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Immunodeficiency Syndromes, Cat 530.e3

Immunodeficiency Syndromes, Cat Client Education
Sheet
VetBooks.ir Diseases and Disorders

BASIC INFORMATION
• FeLV can cause hematologic neoplasia,
myelosuppression, immune-mediated diseases present, a second infectious agent is likely
to be the cause.
Definition (p. 329).
Conditions resulting from a defective immune • FIV is less pathogenic and more likely associ- DIAGNOSIS
response. They may be primary (from an ated with stomatitis or neurologic disorders
inherited defect) or secondary to another (p. 325). Diagnostic Overview
disease. There may be specific defects in B- or • Both FeLV and FIV cause immunodeficiency, • Proving that an immunodeficiency is present
T-lymphocyte function or nonspecific defects in resulting in opportunistic infections. requires specialized testing that is not readily
phagocytic cell function or in skin or mucosal • Almost any infection can occur in cats available to clinicians (e.g., lymphocyte
integrity. infected with retroviruses. immunophenotyping, counting CD4 cells).
○ Examples: bacterial (stomatitis, pyoderma), • One may assume that cats with ret-
Synonym fungal (dermatophytosis, cryptococcosis), roviral infections have some degree of
Immune or immunologic deficiency protozoal (toxoplasmosis, cryptosporidi- immunodeficiency.
osis), other viral (feline infectious peri-
Epidemiology tonitis, panleukopenia), and hemotropic Differential Diagnosis
SPECIES, AGE, SEX mycoplasmosis (Mycoplasma haemofelis) • Any unusual, persistent, or recurring
• A rare neutrophil granulation defect is seen ○ Some infections may be persistent or infection in any cat may be secondary to a
in young Persian cats with Chédiak-Higashi recurrent. retroviral infection.
disease syndrome. ○ Neutropenia: more common with FeLV • Neutropenia can also be caused by other
• Congenital hypotrichosis occurs in Birman than FIV, increases risk for infections primary bone marrow disease, drugs, toxins,
cats, born athymic and without hair. or a viral or overwhelming bacterial infec-
• Other known specific immunologic defects in Clinical Presentation tion. Some cats have physiologic/idiopathic
cats are acquired and secondary to retroviral HISTORY, CHIEF COMPLAINT neutropenia (diagnosis of exclusion), show no
infections (feline leukemia virus [FeLV], Signs may be vague, such as weight loss and clinical signs, and have a normal life span.
feline immunodeficiency virus [FIV]). These lethargy, or may be associated with a specific • In addition to immunodeficiency, immu-
infections can occur at any age and in either infection. Common clinical signs are salivation nosuppression may occur for a variety
sex, although young cats are most susceptible or dysphagia from stomatitis, chronic nasal of reasons (e.g., chemotherapy, chronic
to FeLV infection. discharge from bacterial or viral rhinitis, and glucocorticoid use, severe systemic disease)
diarrhea from enteritis. and can contribute to secondary infection.
GENETICS, BREED PREDISPOSITION
• Persian cats with a dilute smoke-gray coat PHYSICAL EXAM FINDINGS Initial Database
color and yellow irises may have Chédiak - • Stomatitis (lymphocytic-plasmacytic pro- • CBC
Higashi syndrome. liferative type): more commonly associated ○ FeLV/FIV: anemia, neutropenia, and/or
• Hypotrichosis is an autosomal reces- with FIV than FeLV (FIV > FeLV) thrombocytopenia. Persistent lymphopenia
sive condition that is uniformly fatal in • Signs of neurologic disorders, especially may occur but is nonspecific.
neonates. dementia or muscle twitching: FIV > FeLV ○ Chédiak-Higashi syndrome produces
• Gingivitis: FeLV ≈FIV characteristic large granules in neutrophils.
RISK FACTORS • Anemia: FeLV > FIV • Urinalysis to evaluate for proteinuria or
• Greater FeLV propagation in crowded multi- • Lymphadenopathy (reactive; may be caused infection
cat households or shelters by bartonellosis): FeLV > FIV • Serum biochemistry profile: usually unre-
• FIV occurs primarily in adult, outdoor, intact markable but rarely reflects visceral organ
male cats. Etiology and Pathophysiology involvement with opportunistic infections
• FIV and FeLV travel easily through the blood • Chédiak-Higashi–associated immune defi- (e.g., pyelonephritis, bacterial translocation
and can be spread by blood transfusion. ciency (rare disorder) is linked with abnormal by portal circulation). Serum globulin level
neutrophil granules with abnormal function may be normal or elevated.
CONTAGION AND ZOONOSIS and survival. • FeLV (antigen) and FIV (antibody) ELISA
• FeLV is spread through contact with saliva, • FeLV/FIV (retroviral)–associated immuno- blood tests are excellent for initial screening.
respiratory secretions, and milk. Kittens < 4 deficiency ○ Maternal antibody and vaccination
months old are at greatest risk from queens ○ The subset of lymphocytes most affected interfere with FIV testing but not FeLV
or other cats. is the CD4 helper T cell. The ratio of testing.
• FIV is less contagious and is spread primarily CD4 to CD8 cytotoxic T cells is also
through bite wounds. decreased. Advanced or Confirmatory Testing
• No known zoonotic risk for FeLV or FIV ○ Also described with FeLV: secondary • A positive ELISA test result for FeLV or
decreased ability of B cells to respond to FIV in a cat with signs compatible with an
GEOGRAPHY AND SEASONALITY new antigens immunodeficiency syndrome is likely to be
Both viruses have worldwide distribution. ○ Thymic atrophy in neonatal kittens can accurate. A positive test result for a healthy
Prevalence of FeLV has decreased in countries cause fading kitten syndrome. cat without known risk factors may be a
where testing and vaccination are used. ○ FIV is less pathogenic than is FeLV. Many false-positive. Results are confirmed by IFA
cats infected with FIV can live for many for FeLV or by Western blot for FIV.
ASSOCIATED DISORDERS years without signs of illness. • Polymerase chain reaction (PCR) testing
• Chédiak-Higashi syndrome: slight increased ○ Neither FeLV nor FIV causes cytopathic for these retroviruses is somewhat variable
risk for bacterial infections. Bleeding may changes or inflammation in tissues during between labs but may also be used as a
occur from platelet dysfunction. the chronic stage of disease. If a fever is confirmatory test.

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