title: Exposure of mares to processionary caterpillars (Ochrogaster lunifer) in early pregnancy: an additional dimension to equine amnionitis and fetal loss.
abstract: BACKGROUND
  Equine amnionitis and fetal loss (EAFL) is an unusual form of abortion in mid- to late-gestation mares, first identified in Australia in 2004. It has been shown that both whole processionary caterpillars (Ochrogaster lunifer) and their shed exoskeletons can induce abortion in mares during midgestation. These abortions exhibited gross pathology and bacteriology results consistent with field cases of EAFL.
  
  
  OBJECTIVE
  To determine whether exposure of mares to the shed exoskeletons of processionary caterpillars can induce abortion in the preplacentation (<35 days' gestation) and early placentation (45-60 days) stages of pregnancy.
  
  
  METHODS
  In vivo experimental study.
  
  
  METHODS
  Mares less than 35 days' gestation and between 45 and 60 days' gestation were exposed to a slurry of shed processionary caterpillar exoskeletons by nasogastric intubation. Mares were monitored by clinical examination daily. Transrectal ultrasonography was performed daily (control and treated preplacentation mares, treated early placentation mares) or every second day (control early placentation mares). Uterine swabs were collected from mares that aborted. All live foals underwent a clinical examination. Placentas were examined, with sampling for bacteriology and histopathology if appropriate.
  
  
  RESULTS
  Abortions occurred in treated mares in both experiments without signs of impending abortion. One mare aborted in the embryonic stage experiment and 2 in the early placentation experiment. Embryonic and fetal death was detected on transrectal ultrasonography prior to abortion. In the early placentation experiment, one foal was born 5 weeks preterm and was very small, with laxity of the tendons in all limbs. Enteric or environmental bacteria, consistent with EAFL, were isolated from the mares that aborted. Focal mucoid placentitis lesions were present on the placentas of 2 treated mares, one from each experiment.
  
  
  CONCLUSIONS
  Processionary caterpillar exposure may be associated with EAFL-related embryonic and early fetal loss in mares. Processionary caterpillars may also play a role in the occurrence of focal mucoid placentitis.
authors: Equine Research Unit, School of Agriculture and Food Sciences, The University of Queensland, Australia.
authors: A J
authors: AJ
authors: Cawdell-Smith
authors: K H
authors: KH
authors: Todhunter
authors: N R
authors: NR
authors: Perkins
authors: W L
authors: WL
authors: Bryden
mesh_terms: D037881:Aborted Fetus; D000019:Abortifacient Agents / Q000633:toxicity*; D000034:Abortion, Veterinary; D000818:Animals; D001315:Australia; D002821:Chorioamnionitis / Q000139:chemically induced / Q000662:veterinary*; D005260:Female; D005313:Fetal Death / Q000139:chemically induced / Q000662:veterinary; D006734:Horse Diseases / Q000139:chemically induced*; D006736:Horses; D007814:Larva; D009036:Moths / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000662:veterinary
chemical_list: D000019:Abortifacient Agents
keywords: abortion; embryo; equine amnionitis and fetal loss; fetus; horse; processionary caterpillar