Age-Related Comparative Study of C-Reactive Protein, Lipid Profile Biomarkers, and Strongyle Nematode Gastrointestinal Parasitic Burden in Horses.

Overview

• This study investigates how inflammatory and lipid biomarkers vary with age in horses infected by gastrointestinal (GI) strongyle nematodes in Southern Thailand.
• It explores the potential of using C-reactive protein (CRP) and lipid profile parameters as indicators for parasite infection and disease progression.

Introduction and Background

• Gastrointestinal parasitic infection is a common and economically impactful health issue in horses worldwide.
• Infective parasite stages can trigger systemic inflammation and disrupt normal lipid metabolism in horses.
• Age-related chronic low-grade inflammation may compound infection severity and overall equine health.

Objective

• The study aims to evaluate serum levels of C-reactive protein (CRP), a marker of inflammation, and lipid profile parameters in horses to identify age-related patterns associated with GI parasitic infections.
• It focuses on horses living in a high prevalence region for GI helminth infections in Southern Thailand.

Methods

• Sample Size: 77 horses categorized into four age groups:
  • Foal (<1 year)
  • Yearling (1–3 years)
  • Adult (4–10 years)
  • Aged (>10 years)
• Parasitology:
  • Fecal samples were examined for helminth eggs using a modified McMaster technique to determine fecal egg counts (EPG).
  • Strongyle nematodes identified included cyathostomins and Strongylus vulgaris with over 60% prevalence in all age groups.
• Biomarker Analysis:
  • Serum CRP levels were measured as a marker of systemic inflammation.
  • Lipid profiles determined included total cholesterol (TC), total triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C).
  • Ratios of LDL: HDL and TC: HDL were calculated to assess lipid balance and potential cardiovascular risk.

Results

• High prevalence (>60%) of strongyle nematode infections was consistent across all age groups.
• Significant age-related increases were observed in:
  • Serum CRP levels (indicating higher inflammation in older horses)
  • Total cholesterol (TC)
  • Low-density lipoprotein cholesterol (LDL-C)
• Lipid ratios (LDL: HDL and TC: HDL) also varied with age and infection status.
• Diagnostic thresholds identified for predicting strongyle infection included:
  • CRP level > 0.49 mg/L (sensitivity 72.97%, specificity 75%)
  • LDL: HDL ratio > 2.476 (sensitivity 64.29%, specificity 71.43%)
  • TC: HDL ratio > 5.198 (sensitivity 51.22%, specificity 83.33%)

Conclusions and Implications

• The study highlights that both inflammatory response and alterations in lipid metabolism correlate with the age and parasitic burden in horses.
• CRP and cholesterol index ratios show promise as prognostic biomarkers for detecting and monitoring equine strongyle nematode infections.
• This biomarker approach could improve parasite management strategies by aiding early diagnosis and guiding treatment interventions.
• Monitoring these biomarkers can help maintain horse health and reduce the economic impact of parasitic infections in equine populations, particularly in endemic areas.