Molecular detection of Toxoplasma gondii in an aborted equine fetus and serological evidence of infection in mares enrolled in embryo transfer programs in Brazil.

Overview

• This study investigated the presence of Toxoplasma gondii infection in mares involved in embryo transfer programs in Brazil.
• It reported the first molecular detection of T. gondii in an aborted equine fetus and its placenta in the country and examined the prevalence and risk factors of infection in mares.

Background

• Toxoplasma gondii is a parasite known to cause reproductive losses, especially in goats and sheep.
• The impact of this parasite on horses (mares) is not well studied, leading to underestimation of its effects in equine production.
• The study aimed to fill this knowledge gap by investigating T. gondii infection in mares enrolled in embryo transfer (ET) programs.

Study Objectives

• Perform a serological survey to detect anti-T. gondii antibodies in mares from Northeastern Brazil.
• Detect molecular evidence of T. gondii infection in aborted equine fetuses and placentas.
• Identify potential risk factors associated with T. gondii infection in these mares.

Methods

• Sample Population: 100 mares from farms participating in embryo transfer programs.
• Serological Testing: Detection of anti-T. gondii IgG antibodies using indirect fluorescent antibody assay (IFA) with a cutoff dilution of 1:64; positive samples further titrated.
• Molecular Testing: PCR targeting:
  • The 18S rRNA gene of the Sarcocystidae family (to broadly detect related parasites).
  • The 529-base pair repetitive element specific to T. gondii.
• Samples tested included placentas and fetal organs from three mares in a farm experiencing an abortion outbreak.
• Risk Factor Analysis: Considered presence of cats on farms and abortion history in mares.

Key Findings

• Seroprevalence: 31% of mares tested positive for anti-T. gondii IgG antibodies, indicating a considerable exposure rate.
• Molecular Detection: One aborted fetus and its placenta tested positive for both the Sarcocystidae 18S rRNA gene and the specific 529-bp element of T. gondii, confirming infection.
• Risk Factors:
  • Presence of cats on farms was associated with higher seropositivity in mares.
  • A history of abortion in mares correlated with the presence of antibodies, suggesting a link between infection and reproductive loss.

Significance

• This study presents the first molecular evidence of T. gondii infection in an aborted equine fetus and placenta in Brazil, which had previously not been documented.
• Shows that T. gondii infection is present in mares involved in ET programs, suggesting potential risks to reproductive health in equine production.
• Highlights important risk factors such as farm cat populations and abortion history, pointing to possible management changes to reduce infection risk.
• Contributes valuable data to veterinary parasitology and equine reproductive health fields, encouraging further research and surveillance.