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Coccidioidomycosis
in dogs and cats |
Clinical disease in dogs:
Following a 1-3 week incubation period, coccidioidomycosis
begins as a primary, limited pulmonary disease that may be accompanied
by mild respiratory signs or may be subclinical. If the dog's
immune system is unable to contain the infection at this stage,
it progresses to a disseminated pulmonary disease (interstitial
radiographic pattern +/- hilar lymphadenopathy) with more intensive
respiratory signs/cough and, ultimately, a systemic infection.
- The tissue most commonly affected systemically is bones,
especially the metaphyses of long bones.
- Skin lesions are also common. The disease may present as
a primary, restricted cutaneous disease.
- Less commonly affected tissues include:
- heart (See recent case of constrictive pericarditis-Shubitz
et al. 2001)
- eyes
- CNS
Clinical disease in cats:
Clinical disease in similar to that in dogs. Skin lesions are
particularly common, but bone lesions are less commonly diagnosed
than in dogs.
Diagnosis of coccidioidomycosis in dogs and cats:
- cytology,
histopathology
- detection of "spherules" containing "endospores"
rather than classical yeast organisms
- serology:
- Tube precipitin (TP) (primarily detects just IgM), latex
agglutination (LAT), agar gel immunodiffusion (AGID) and ELISA
tests are all available. Of these, the TP test primarily detects
just IgM; the AGID and ELISA can be quite sensitive for screening,
although the ELISA may cross-react with Blastomyces dermatitidis.
- A complement fixation assay is used for confirmation of infection
and for quantification of the extent of disease in the body.
- Titers increase with severity and chronic disease and decrease
following therapy.
