In vitro cultivation of Trypanosoma equiperdum: Comparison of in vitro and in vivo antigens for an ethical and sustainable serological diagnosis of Dourine.

Overview

• This research evaluates an in vitro method for cultivating Trypanosoma equiperdum, the parasite causing Dourine in horses.
• It compares the antigens produced in vitro with those traditionally grown in vivo in animals for use in serological diagnostic tests, aiming for an ethical and sustainable alternative.

Background and Importance

• Trypanosoma equiperdum is a protozoan parasite responsible for Dourine, a sexually transmitted disease affecting equines.
• The disease can present as chronic or acute, causing serious veterinary health issues and economic losses.
• Currently, there are no vaccines available, so disease management relies on culling infected animals and strict sanitary measures.
• Traditional antigen production requires infecting live animals (in vivo), raising ethical concerns, biosafety risks, and logistical challenges.

Objectives of the Study

• Develop and evaluate an in vitro cultivation method for producing T. equiperdum antigens that eliminates the need for animal infection.
• Compare the in vitro produced antigens with conventional in vivo antigens using serological diagnostics.
• Validate the diagnostic methods according to standards set by WOAH (World Organisation for Animal Health).
• Assess diagnostic performance and ethical sustainability to support animal welfare and reduce reliance on animal use.

Methodology

• Produced T. equiperdum antigens using both traditional in vivo infection of animals and the developed in vitro cultivation technique.
• Utilized two serological diagnostic tests:
  • Complement Fixation Test (CFT)
  • Indirect Fluorescent Antibody Test (IFAT)
• Followed WOAH guidelines for validation involving:
  • Sensitivity and specificity assessment
  • Repeatability (same results on repeated tests)
  • Reproducibility (consistency across different conditions/labs)

Key Findings

• The sensitivity and specificity of antigens produced in vitro were comparable to those produced in vivo.
• Precision testing revealed 100% concordance in both repeatability and reproducibility for the diagnostic assays.
• IFAT demonstrated excellent agreement with CFT results, supporting its role as a reliable confirmatory test in eradication programs.
• The in vitro production methods significantly reduced biosafety risks and removed animal housing and infection challenges.

Significance and Impact

• By eliminating the need for animal infection, the in vitro method aligns with the 3Rs principle:
  • Replacement: avoids using animals
  • Refinement: improves animal welfare by minimizing distress
  • Reduction: decreases the number of animals needed
• This method offers a sustainable and ethical alternative for producing T. equiperdum antigens.
• It facilitates safer, more efficient, and ethically sound diagnostic testing in veterinary practice.
• Supports improved disease management, better animal welfare, and promotes sustainable veterinary diagnostics globally.