Characterisation of serum IgG(T) responses to potential diagnostic antigens for equine cyathostominosis.

The research investigates two types of diagnostic antigens for determining the burden of cyathostomin nematodes in horses. Findings indicate that the test involving a combination of Cy-GALA and Cy-CID proteins from different species produced the best predictive values for infection.

Cyathostomin Infection in Horses

• The study focuses on cyathostomin nematodes, common parasites found in horses. These worms usually spend a substantial period as larvae embedded in the intestinal walls of the horse.
• Emergence of these larvae can cause severe colitis, which can be life-threatening. Despite this, existing diagnostic methods using faecal egg count tests do not provide a reliable indication of the severity of the infection.

Investigating Diagnostic Antigens

• The researchers previously identified the cyathostomin Gut Associated Larval Antigen (Cy-GALA) as a potential marker for the severity of the infection. In this study, they examined both the Cy-GALA and an additional protein, the Cyathostomin Immuno-diagnostic antigen (Cy-CID).
• They used ELISA analyses to investigate serum IgG(T) responses to these proteins, generated from different cyathostomin species.
• The effectiveness of these proteins as diagnostic indicators was evaluated using Receiver Operator Characteristic curve analysis.

Diagnostic Protein Combinations

• Based on this analysis, several combinations of these proteins were tested to determine the most effective markers for infection status. Three combinations were examined: CT3 (which contained Cy-GALA proteins from two species, and a Cy-CID protein from another), CT5 (containing Cy-GALA proteins from five species), and CT6 (all CT5 components, plus a Cy-CID protein from an additional species).
• The best predictive values for cyathostomin infection were obtained using the CT3 and CT6 combinations. The proteins in CT3 come from the most frequently reported species: Cyathostomum catinatum, Cylicocyclus nassatus, and Cylicostephanus longibursatus.
• The researchers recommend the CT3 combination for future development, as this offers a potential solution in a commercially viable format for a diagnostic test.