Objective—To determine the seroprevalence of antibodies
against Coccidioides immitis in healthy horses
residing in an area in which the organism is endemic.
Animals—197 healthy horses (in which coccidioidomycosis
had not been previously diagnosed) that
resided in an area of Arizona in which coccidioidomycosis
Procedure—Of the horses evaluated at the Arizona
Equine Medical and Surgical Center during a 6-month
period, 197 with no clinical signs of coccidioidomycosis
were randomly selected for inclusion in the study;
sera were evaluated for IgM and IgG antibodies
against C immitis via an immunodiffusion assay (IgGpositive
samples were assessed quantitatively).
Within 6 months, recheck titer evaluations were
attempted for all seropositive horses.
Results—Serum antibodies against C immitis were
detected in 8 of 197 horses (seroprevalence, 4.06%).
Results of serologic assays were positive for IgG antibodies
and negative for IgM antibodies in 7 horses
and positive for both IgG and IgM antibodies in 1
horse; reciprocal serum IgG antibody titers were low
(none > 8). Follow-up serologic data were obtained
from 5 horses; compared with initial findings, horses
had become seronegative or titers were unchanged
or decreased. Duration of residence in the area was
significantly shorter for seropositive horses than for
Conclusions and Clinical Relevance—Serum antibodies
against C immitis may rarely be detected in healthy
horses residing in an area in which the disease is
endemic; any horse with a detectable serum antibody
titer should be reevaluated after an interval of at least 3
weeks. (J Am Vet Med Assoc 2005;226:1888–1892)
Objective—To determine clinical, clinicopathologic,
and radiographic abnormalities in dogs with coccidioidomycosis.
Design—Retrospective case series.
Procedure—Clinical information and results of clinicopathologic
testing were obtained from medical
records. Thoracic radiographs were reviewed to characterize
Results—Dogs ranged from 1 to 10 years old at the
time of diagnosis, with 12 dogs being between 1 and
3 years old. Historical complaints included cough,
lameness, signs of head or neck pain, and difficulty
breathing. Mild anemia, neutrophilia, and monocytosis
were common. All dogs had hypoalbuminemia,
and 8 of 15 had hyperglobulinemia. Thoracic radiographs
of 19 dogs were reviewed. Pulmonary infiltrates
were seen in 13 dogs, with an interstitial pattern
of infiltration being most common. Hilar lymphadenopathy
was seen radiographically in 10 dogs.
Serum from 20 dogs was tested for antibodies
against Coccidioides immitis. One dog was positive
for IgM antibodies, 5 were positive for IgM and IgG
antibodies, and 14 were positive for IgG antibodies.
Quantitative IgG titers measured in 14 dogs ranged
from 1:2 to 1:128 (median and mode, 1:32). In 6 dogs,
histologic examination of biopsy samples revealed
fungal spherules ranging from 8 to 70 μm in diameter.
Conclusions and Clinical Relevance—Results suggest
that in dogs, coccidioidomycosis may be associated
with a wide spectrum of nonspecific respiratory and
musculoskeletal abnormalities. The chronic nature of
the disease makes diagnosis difficult, even in regions in
which the organism is endemic. (J Am Vet Med Assoc