Rhodococcus equi and genetic susceptibility: assessing transferrin genotypes from paraffin-embedded tissues

Area of Science:

• Veterinary Microbiology
• Animal Genetics
• Equine Infectious Diseases

Background:

• Rhodococcus equi is a soil-borne pathogen causing foal infections and mortality.
• Transferrin, an iron-binding protein, exhibits polymorphism in horses and may influence disease susceptibility.
• Understanding transferrin's role could elucidate variations in foal susceptibility to R. equi.

Purpose of the Study:

• To compare biochemical and DNA-based transferrin typing methods.
• To assess the feasibility of molecular typing from archival equine tissue samples.
• To investigate potential associations between transferrin type and foal mortality due to R. equi.

Main Methods:

• Biochemical typing and DNA sequencing were used to analyze transferrin in 41 horses.
• DNA was successfully extracted and typed from archival paraffin-embedded tissue samples.
• Allele frequencies of transferrin were analyzed in Thoroughbred foals that died from R. equi.

Main Results:

• Biochemical and DNA sequencing methods for transferrin typing showed good correspondence.
• Archival tissue samples yielded viable DNA for successful transferrin typing.
• An excess of the transferrin F allele and a deficiency of the D allele were observed in foals that died from R. equi (P < 0.05).
• Foal age, sex, and year of collection were not significantly associated with transferrin type.

Conclusions:

• DNA sequencing is a viable method for transferrin typing, even from archival samples.
• A potential association exists between specific transferrin allele frequencies and foal mortality caused by Rhodococcus equi.
• Further research is warranted to confirm the link between transferrin polymorphism and susceptibility to R. equi infections in foals.