protozoal abortion in mares: a review of pathogens, diagnosis and treatment approaches

Protozoan contamination poses a significant challenge in veterinary medicine, particularly concerning equine reproductive health. various protozoa can incite diseases, some of which are capable of transplacental transmission, leading to abortion in mares. this study meticulously gathers data on protozoa identified in aborted fetuses and affected mares, alongside diagnostic methods and clinical symptoms. the absence of herpes viruses and other viral pathogens in affected individuals suggests a parasitic etiology for these abortion cases. equine gestation lasts approximately 335 to 340 days, during which specific protozoan infections may traverse the placenta at various gestational stages, often correlating with elevated prostaglandin levels that precipitate abortion. among the most notorious culprits are neospora species, notably neospora caninum and neospora hughesi, which are recognized as significant abortifacients around the 280-day mark. diagnosis can be achieved through analysis of tissues from the liver, brain, skeletal muscles, heart, lungs, and placenta via elisa and pcr techniques. the protozoan theileria equi also contributes to fetal loss, frequently occurring in the fourth and fifth months of pregnancy, with infection rates peaking between days 40 and 150, coinciding with the histiotrophic phase. diagnostic sampling involves various tissues and fluids, and methods such as pcr, elisa, and ifat are employed for detection. while imidocarb is used to treat t. equi infections, it does not effectively prevent abortions. other protozoan agents, such as toxoplasma gondii and sarcocystis neurona, are implicated in abortions, often resulting in neurological disorders for both mares and fetuses. treatment options like nitazoxanide and toltrazuril are available for s. neurona and t. gondii, respectively. this study analyzed 43 articles from prominent databases, yielding 14 relevant studies. notably, after excluding viral factors, protozoan agents t. gondii, s. neurona, and t. equi were associated with the highest abortion rates, underscoring the importance of regular examinations and antiparasitic treatment to mitigate risks.