Endogenous transplacental transmission of Neospora hughesi in naturally infected horses.

The research examined the potential of Neospora hughesi, a parasite, being transmitted from mare to foal during pregnancy. The study concluded that this parasitic infection can indeed be passed from the mother horse to the offspring, contributing to its persistence in the population.

Study Objective and Methodology

• The study aimed to understand the vertical transmission potential of Neospora hughesi – a parasitic infection in horses. Specifically, it sought to investigate whether N. Hughesi can be passed from an infected mare (mother horse) to her offspring during pregnancy.
• The study involved 74 mare-and-foal pairs over a period of 2 years. The research interest started after a diagnosis of Neuronal neosporosis (N. hughesi infection) in a weanling foal.
• The researchers tested serum and colostrum of mares before and after giving birth, serum of the foals after birth, and then at 3-month intervals thereafter. The testing was done using an indirect fluorescent antibody test (IFAT).
• Furthermore, screenings were performed on whole blood and colostrum samples and placenta for any trace of N. hughesi, using real-time PCR.

Findings

• The study found that over half of the mares, 52% in 2006, carried the N. hughesi antibody with a smaller fraction of 6% in 2007, revealing a significant decline in the infection prevalence over time.
• The mares shed colostral antibodies against the parasite, with 96% of them doing so in the first year of study, and 11% in the next year.
• Most of the newborn foals were seronegative to N. hughesi, except three that carried presuckle antibodies, suggesting they inherited the infection from their mothers.
• Additionally, 15 foals showed passive transfer of the parasite’s antibodies, further pointing towards the mother-to-offspring transmission of the infection.
• The study also tracked seroconversion – the period when a specific antibody becomes detectable in the blood – in 10 foals and 9 mares over the 2-year study.
• All blood and colostrum samples were found PCR negative for the parasite’s presence. Only one placenta tested positive for N. hughesi.

Conclusions

• The research concluded that it is possible for N. hughesi to be passed from an infected mare to her foal during pregnancy.
• The study highlights the significance of this finding, as transplacental transmission ensures the continuous presence and spread of this parasitic infection in future generations of horses.