Transplacental transmission of Babesia equi (Theileria equi) from carrier mares to foals.

The research article concentrates on the study of transplacental transmission of a parasite, Theileria equi, from carrier mares to their foals, resulting in the foals developing fatal equine piroplasmosis. This is the first study of its kind in Punjab, India, describing two such cases.

Investigation and Findings

• The research was prompted by the observation of clinical signs in two newborn foals from Thoroughbred mares.
• These foals were notably found with annular and maltese cross-shaped parasites inside their red blood cells. This is a definitive sign of high parasitaemia, indicative of an infection by T. equi.
• The blood samples from these foals showed reductions in white blood cells and neutrophils, and a mild shift to immature forms of the cells, indicating an ongoing immune response to the infection.
• The foals’ anemia was of the macrocytic normochromic type, implying that the size of the red blood cells was larger than normal but with normal hemoglobin.

Clinical Symptoms

• The foals exhibited intense yellow discoloration of their mucous membranes, signifying jaundice. This is a condition where bilirubin, a yellow pigment and the byproduct of red blood cells’ destruction, accumulates in the blood and tissues.
• The primary clinical symptom distinguishing equine piroplasmosis from other diseases is jaundice. However, this symptomology is easily confused with neonatal isoerythrolysis (NI), a condition more typically associated with jaundice. NI features the destruction of a foal’s red blood cells by antibodies absorbed through the milk of their mother.

Implications and Recommendations

• This study underlines the potential of transplacental transmission of T. equi in endemic regions, posing a serious threat to equine health.
• Therefore, in geographical locales where equine piroplasmosis is prevalent, newborn foals showing symptoms of jaundice should be screened for equine piroplasmosis as well as reduction in blood cell numbers.