Page 950 - Clinical Small Animal Internal Medicine

888 Section 9 Infectious Disease

immune‐ compromised animals. Nonspecific signs of logic examination, and immunofluorescence staining.
VetBooks.ir FHV‐1 infection may include depression, anorexia, and False‐negative results may occur with any of these
assays as virus may not be present in specimens.
pyrexia. Respiratory signs include sneezing and con-
junctivitis associated with serous ocular and nasal dis-
ple acquisition and transport techniques for culture.
charge. Nasal turbinate destruction can lead to Laboratories should be contacted for appropriate sam-
recurrent rhinitis and sinusitis. Coughing and dyspnea The sensitivity and specificity of PCR may vary depend-
can develop in more severe cases. Ocular and nasal dis- ing on the laboratory and design of the test. It should
charge that becomes mucoid or purulent may signal also be kept in mind that PCR may not detect all strains,
secondary bacterial infection. In addition to conjuncti- particularly for calicivirus, due to variability in nucleic
vitis, keratitis and corneal ulcerations also occur with acid target sequences. Positive PCR results may occur
FHV‐1 infection. Dendritic corneal ulcerations are in healthy cats, so a positive result does not necessarily
considered pathognomonic for infection with FHV‐1. mean that clinical signs may be attributed to infection.
FHV‐1 might also play a role in other forms of ocular In addition, vaccination with attenuated virus may
disease. Skin ulceration and herpetic dermatitis may cause false‐positive PCR results. Serologic testing is
also be caused by FHV‐1. also available, but it is not easily interpreted as vaccina-
Feline calicivirus causes a range of clinical signs due to tion and previous exposure are common for both
strain variability. Similar to FHV‐1, upper respiratory viruses and the presence of antibody may not indicate
signs predominate. Sneezing and ocular discharge asso- active infection.
ciated with conjunctivitis are common. In contrast to
FHV‐1 infection, corneal ulceration does not typically
occur with FCV infection. However, oral ulceration is Therapy
common, making FCV a top differential diagnosis for
oral ulcerations in cats. Stomatitis may be severe, and In cases of acute respiratory disease, supportive care
lead to excessive ptyalism. Other signs of FCV infection including fluid therapy and/or nutritional support may
include depression, pyrexia, anorexia, enlarged lymph be indicated. Clinical signs resolve within 2–3 weeks.
nodes, and acute lameness. Infection with highly viru- Judicious administration of appropriate antibiotics is
lent strains of FCV causing VSD results in severe signs indicated if evidence of secondary bacterial infection or
such as high fever, cutaneous edema, jaundice, other co‐infection with Chlamydia, Mycoplasma or Bordetella
signs of multiorgan failure, and death. is present. For more severe or recurrent disease, or if
keratoconjunctivitis or stomatitis is present, more
aggressive specific therapy may be indicated, including
Diagnosis antiviral or immunomodulating agents, and for stomati-
tis, dental extractions, antimicrobial treatment, and anti-
History, clinical signs, and evidence of possible immu- septic mouthwashes.
nosuppression (due to retroviral infection, stress or Most antiviral therapies developed for human herpes-
drug administration, for example) should increase the viruses are too toxic for oral administration in cats,
index of suspicion for infection with one or both although the use of famciclovir appears promising.
viruses. For cats with signs of upper respiratory disease, Topical use of idoxuridine, vidarabine, and other select
diagnosis is usually made based on clinical signs alone. nucleoside analogs appears beneficial for treatment for
Specific laboratory tests documenting infection or ocular disease. The therapeutic potential of feline inter-
exposure may be used to help confirm infection, par- feron‐omega on FHV‐1 replication is under investiga-
ticularly in patients with more severe or atypical clini- tion. The use of oral L‐lysine to decrease clinical signs or
cal signs, although each has limitations. Complete infection with FHV‐1 infection has shown conflicting
blood count (CBC) and serum chemistry findings are results.
not specific in cats with upper respiratory disease
caused by FHV‐1 or FCV, although cats with stomatitis
caused by FCV may be hyperglobulinemic. Cats with Prognosis
VSD may have anemia, thrombocytopenia, neutro-
philia, and lymphopenia. Hypoalbuminemia, elevated In general, cats will recover but both viruses persist, with
alanine aminotransferase (ALT) and aspartate ami- reactivation of FHV‐1 occurring due to stressors. FCV
notransferase (AST), elevated bilirubin, and increased carriers can shed virus continuously, increasing the like-
creatine kinase (CK) also occur. lihood of infecting other cats. FCV infection with strains
Direct testing for the presence of virus may include associated with VSD has been associated with greater
culture, polymerase chain reaction (PCR), histopatho- than 50% mortality.