Page 1521 - Small Animal Internal Medicine, 6th Edition

CHAPTER 96 Polysystemic Viral Diseases 1493

TABLE 96.2
VetBooks.ir Clinical Syndromes Associated With FIV Infection and Possible Opportunistic Agents

CLINICAL SYNDROME
OPPORTUNISTIC AGENTS
PRIMARY VIRAL EFFECT
Dermatologic/otitis externa None Bacterial; atypical Mycobacterium; Otodectes cynotis;
Demodex cati; Notoedres cati; dermatophytosis;
Cryptococcus neoformans; cowpox
Gastrointestinal Yes; small-bowel diarrhea Cryptosporidium spp.; Cystoisospora spp.; Giardia spp.;
Salmonella spp.; Campylobacter spp. others
Glomerulonephritis Yes Bacterial; FeLV, FIP, SLE
Hematologic Yes; nonregenerative anemia; Mycoplasma haemofelis; FeLV; Bartonella henselae?
neutropenia; thrombocytopenia
Myocarditis; hypertropic Yes Bartonella spp., T. gondii
cardiomyopathy
Neoplasia Yes; myeloproliferative disorders FeLV
and lymphoma
Neurologic Yes; behavioral abnormalities Toxoplasma gondii; C. neoformans; FIP; FeLV, B.
henselae?
Ocular Yes; pars planitis, anterior uveitis T. gondii; FIP; C. neoformans, FHV-1, B. henselae
Pneumonia/pneumonitis None Bacterial; T. gondii; C. neoformans
Pyothorax None Bacterial
Renal failure Yes Bacterial; FIP; FeLV
Stomatitis None Calicivirus; overgrowth of bacteria flora; candidiasis, B
henselae?
Upper respiratory tract None FHV-1; calicivirus; overgrowth of bacterial flora;
Cryptococcus neoformans
Urinary tract infection None Bacterial

FeLV, Feline leukemia virus; FHV-1, feline herpesvirus type 1; FIP, feline infectious peritonitis; FIV, feline immunodeficiency virus; SLE, systemic
lupus erythematosus.

Antibodies against FIV are detected in serum in clinical infection. The biggest problem with FIV RT-PCR assays to
practice most frequently by enzyme-linked immunosorbent date is lack of standardization among laboratories and the
assay (ELISA). Saliva can be used instead of serum in frac- potential for both false-positive and false-negative results
tious cats or in facilities that do not have a veterinarian (Crawford et al., 2005).
available at all times (Westman et al., 2016a). Test results for Detection of antibodies against FIV in the serum of cats
FIV antibody can vary amongst test kits (Levy et al., 2017; that have not been vaccinated against FIV documents expo-
Westman et al., 2017). Whether antibodies induced by the sure and correlates well with persistent infection but does
FIV vaccine available in some countries also varies by test not correlate with disease induced by the virus. Because
kit (Westman et al., 2017). Results of PCR or virus isolation many clinical syndromes associated with FIV can be caused
can be used to distinguish a previously vaccinated cat if the by opportunistic infections, further diagnostic procedures
history is not known (Nichols et al., 2017). Clinical signs can may determine treatable etiologies (see Table 96.2). For
occur before seroconversion in some cats, and some infected example, some FIV-seropositive cats with uveitis are co-
cats never seroconvert; thus false-negative reactions can infected by T. gondii and often respond to the administration
occur. Results of virus isolation or RT-PCR on blood are of anti-Toxoplasma drugs (see Chapter 98).
positive in some antibody-negative cats. False-positive reac-
tions can occur with ELISA; therefore positive ELISA results Treatment
in healthy or low-risk cats should be confirmed by Western Because FIV-seropositive cats are not necessarily immuno-
blot immunoassay or RT-PCR. Kittens can have detectable, suppressed or diseased from FIV, the cat should be evaluated
colostrum-derived antibodies for several months. Kittens and treated for other potential causes of the clinical syn-
younger than 6 months that are FIV seropositive should be drome (Tasker et al., 2006a). Some FIV-seropositive cats are
tested every 60 days until the result is negative. If antibodies immunodeficient; if infectious diseases are identified, bacte-
persist at 6 months of age, the kitten is likely infected. Virus riocidal drugs administered at the upper end of the dosage
isolation or PCR on blood can also be performed to confirm should be chosen. Long-term antibiotic therapy or multiple