Equine amnionitis and fetal loss (EAFL) is an unusual form of abortion that occurs in mid- to late-gestation mares living in Australia. It is associated with exposure to the hairs of the processionary caterpillar (Ochrogaster lunifer
). EAFL is very similar to mare reproductive loss syndrome (MRLS)
, which occurs in mares in the United States, associated with exposure to the hairs of the eastern tent caterpillar (Malacosoma americanum
EAFL was first identified in Australia in 2004, when an outbreak of abortions occurred in mares living in the Hunter Valley region of New South Wales from mid-March to November.
It is thought that upon grazing, horses may come into contact with hairs from skin shed from the caterpillars that had been blown from their nests. Processionary caterpillars are known to build their nests in many tree and shrubs that are commonly found in horse pastures.