Passive transfer of Theileria equi antibodies to neonate foals of immune tolerant mares.

This research examines how antibodies against Theileria equi, a parasite causing equine babesiosis, are passively transferred from immune tolerant mares to their newborn foals. The study found that these antibodies, while initially present in high amounts, diminish in the foals 63 to 77 days-post foaling.

Introduction and Context

• The research is primarily concerned with equine babesiosis, a disease affecting horses globally. TheILERIA EQUILA causes this disease, a parasite transmitted via ticks.
• This disease results in significant economic loss in the horse rearing industry.
• Horses raised in areas endemic with this disease often become infected at a young age and develop immune tolerance, continuing to carry the parasite without showing symptoms.

Methodology

• The researchers selected pony and donkey mares already infected with T. equi and monitored the levels of T. equi antibodies in their newborn foals for the first 90 days after birth.
• They tested for these antibodies using Dot-ELISA, a diagnostic technique that detects specific proteins in a sample, using serum samples from the foals and their dams.
• They also monitored the foals and dams for the presence of the T. equi parasite itself, using PCR, a common method for amplifying and thereby detecting specific DNA sequences.

Results

• The dams had very high antibody levels.
• While the newborn foals initially had high antibody levels, these declined to less than a third of their initial levels between 63 and 77 days after birth.
• The researchers detected the T. equi parasite only in the dam’s blood samples and not in the foals’ samples.

Interpretation and Conclusion

• These results suggest that while pregnant mares can passively transfer their immunity to their foals, this immunity is temporary and starts to decline around two months after the foals are born.
• Therefore, while the mothers are immune tolerant, the foals are born naive to the parasite, meaning they have not yet developed an immune response to it.