Page 1522 - Small Animal Internal Medicine, 6th Edition

1494 PART XIV Infectious Diseases

treatment periods may be required. The only way to deter- shared by cats with scalding water and detergent inactivates
mine if an FIV-seropositive cat with a concurrent infection the virus. Cats with potential exposure from fighting should
VetBooks.ir has a poor prognosis is to treat the concurrent infection. be retested 60 days after the exposure (Goldkamp et al.,
A number of antilentiviral drugs may be effective for the
2008). Cats that are FIV-infected should be housed indoors
treatment of FIV-infected cats, but controlled studies are
ment to the virus and to lessen the affected animal’s chance
largely lacking (Hartmann et al., 2015; Mohammad and at all times to avoid exposing FIV-naïve cats in the environ-
Bienzle, 2012). Administration of interferons has shown of acquiring opportunistic infections. Kittens queened by
clinical benefit in some studies. Oral administration of FIV-infected cats should not be allowed to nurse to avoid
10 IU/kg of human interferon-α led to improved clinical transmission by ingestion of milk; they should be shown to
signs and prolonged survival compared with a placebo- be serologically negative at 6 months of age to document
treated control group in one study (Pedretti et al., 2006). In failure of lactogenic or transplacental transmission before
another study, feline recombinant interferon was adminis- being sold or adopted. In one study, FIV-positive cats housed
tered at 10 U/kg/day subcutaneously (SC) for 5 days in three in groups of ≤ 2 cats had better long-term outcomes than
6
series (starting on days 0, 14, and 60) and was shown to FIV-positive cats housed in large groups (Beczkowski et al.,
improve clinical signs early in the study and prolong survival 2015). A killed vaccine containing immunogens from two
in treated cats (de Mari et al., 2004). In another study with FIV isolates is licensed for use in some countries. However,
recombinant feline interferon omega, neither a subcutane- the efficacy of the vaccine is in question (Westman et al.,
ous protocol nor an oral protocol lessened FIV viremia, but 2016b).
IL-6 was decreased (Leal et al., 2015). The use of feline inter- HIV and FIV are morphologically similar but antigeni-
feron and potential immunomodulatory effects on FIV cally distinct. Antibodies against FIV have not been docu-
infection have been reviewed (Leal and Gil, 2016). Admin- mented in the serum of human beings, even after accidental
istration of bovine lactoferrin by mouth was beneficial in the exposure to virus-containing material (Butera et al., 2000;
treatment of intractable stomatitis in FIV-seropositive cats Dickerson et al., 2012). Cats with FIV infection resulting in
(Sato et al., 1996). Removal of all premolar and molar teeth immunodeficiency may be more likely to spread other zoo-
has also been effective for treatment of intractable stomatitis notic agents into the human environment; clinically ill, FIV-
in some FIV-seropositive cats. seropositive cats should therefore undergo a thorough
Other substances like the reverse transcriptase inhibi- diagnostic evaluation (see Chapter 99).
tor azidothymidine (AZT), melittin, and phosphonate
9-(2-phosphonylmethoxypropyl)-2,6-diaminopurine,
9-(2-phosphonylmethoxyethyl) adenine, or plerixafor have FELINE LEUKEMIA VIRUS
had mixed success in the treatment of FIV and are generally
not used clinically in the United States for management of Etiology and Epidemiology
FIV cats. Human recombinant erythropoietin administra- FeLV is a single-strand RNA virus in the family Retroviridae,
tion increased red blood cell and white blood cell counts, subfamily Oncovirinae. The virus produces reverse tran-
did not increase viral load, and had no measurable adverse scriptase, which catalyzes the reaction, resulting in the for-
clinical effects in FIV-infected cats compared with placebo mation of a DNA copy (provirus) of FeLV viral RNA in the
(Arai et al., 2000) and could be considered for management cytoplasm of infected cells; the provirus is inserted into the
of anemia in FIV-infected cats. In contrast, although admin- host cell genome. On subsequent host cell divisions the pro-
istration of human recombinant granulocyte-monocyte virus serves as a template for new virus particles formed in
colony-stimulating factor (GM-CSF) to FIV-infected cats the cytoplasm and is released across the cell membrane by
increased white blood cell counts in some treated cats, it budding. FeLV is composed of several core and envelope
also induced fever, anti–GM-CSF antibodies, and increased proteins. Envelope protein p15e induces immunosuppres-
viral load; GM-CSF therefore appears to be contraindicated sion. Core protein p27 is present in the cytoplasm of infected
for this syndrome. Cats with FIV and hospitalized cats had cells, peripheral blood, saliva, and tears of infected cats;
lower serum 25-hydroxyvitamin D [25(OH)D] concentra- detection of p27 is the basis of most FeLV antigen tests. The
tions than healthy cats in one study (Titmarsh et al., 2015). envelope glycoprotein 70 (gp70) contains the subgroup anti-
Whether supplementation will have clinical benefit in the gens A, B, or C, which are associated with the infectivity,
management if FIV infections remains to be proven. virulence, and disease caused by individual strains of the
virus. Neutralizing antibodies are produced by some cats
Prevention and Zoonotic Aspects after exposure to gp70. Antibodies against feline oncornavirus-
Housing cats indoors to avoid fighting and testing new cats associated cell membrane antigen (FOCMA) are formed by
before introduction to an FIV-seronegative, multiple-cat some cats but are generally not used clinically.
household will prevent most cases of FIV. Transmission by The principal route of infection by FeLV is prolonged
fomites is unusual because the virus is not easily transmitted contact with infected cat saliva and nasal secretions; groom-
by casual contact, is susceptible to most routine disinfec- ing or sharing common water or food sources effectively
tants, and dies when out of the host after minutes to hours, results in infection. Because the organism does not survive
especially when dried. Cleaning litter boxes and dishes in the environment, feces, urine, fomite, and aerosol