PhD Epidemiology Student UC Davis Davis, CA, United States
Abstract: Background – Coccidioidomycosis [Valley Fever (VF)] is a life-threatening and emerging disease of humans and animals. Currently available serologic tests (agar gel immunodiffusion [AGID]) take days to perform and require experience to perform and interpret. Validation of novel lateral flow assays (LFAs) for horses will allow for more rapid diagnosis and earlier treatment, yielding improved outcomes.
Objectives – To compare results of two novel lateral flow assays (LFAs) to AGID for detection of serum anti-Coccidioides antibodies in horses.
Animals – Serum specimens from horses tested using AGID at the University of California-Davis Coccidioidomycosis Serology Laboratory (UCD-CSL) from December 2024-June 2025 (target 20 seropositive horses and 20 seronegative horses).
Methods – Serum specimens were tested using sōna Coccidioides antibody LFA (IMMY Diagnostics) and a recombinant chitinase-1 LFA (Velox – Cactus Bio) according to manufacturers’ instructions. Investigators interpreting assay results were masked to AGID results. Assay agreement was determined using a Kappa comparison. Sensitivity and specificity for each LFA were determined using AGID as the gold standard reference.
Results – For 14 specimens tested at the time of writing (Figure 1), results for the sõna LFA have agreed perfectly with AGID (Kappa value 1.00, 100% agreement). The Velox LFA showed strong agreement (0.72, 85.7%). The sõna LFA had a 100% sensitivity and specificity. The Velox LFA had a 100% sensitivity and 75% specificity (Figure 1).
Conclusions and Clinical Importance – Preliminary data suggest that these LFAs may expedite diagnosis of equine coccidioidomycosis.
