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 characterize signalment, clinical and laboratory findings, treatment, and outcome in horses with rattlesnake envenomation in northern California.
Design—Retrospective case series.
Animals—58 client-owned horses evaluated for rattlesnake envenomation at 2 referral hospitals from 1992 to 2009.
Procedures—Records of horses with rattlesnake envenomation were reviewed, and data concerning signalment, clinical and laboratory findings, treatment, and outcome were collected. In addition, a rattlesnake-bite severity score (RBSS) was assigned to each horse. Variables were compared between horses that survived and those that did not.
Results—The overall mortality rate was 9%. Nine horses received antivenin; no complications were reported and none of the 9 died. The most common laboratory findings associated with severity of envenomation were thrombocytopenia, hypoproteinemia, hyperlactatemia, and a high RBSS.
Conclusions and Clinical Relevance—Most horses in this study had a good prognosis after being bitten by rattlesnakes. Laboratory and clinical examination findings may be useful for identifying horses with a poorer prognosis. Treatment with antivenin may be beneficial and warrants further evaluation.