Australian Mystery Disease

Reports have been circulating that there is a disease similar to mare reproductive loss syndrome (MRLS) occurring in Australia. In a correspondence, Nigel Perkins, BVSc, MS, Dipl. ACT, FACVSc, of the private consulting firm AusVet Animal Health Services, said, "Between March-November 2004, a number of mares in the Hunter Valley region and in Queensland suffered abortions due to a similar disease process. A small number of farms suffered devastating losses (15 of 25 mares on one farm), while most affected farms had one or two cases. Preliminary data indicate that between 15-20 separate farms may have been affected."

He has termed this problem equine amnionitis and fetal loss (EAFL).

John Freestone, DVM, Dipl. ACT, resident veterinarian at Coolmore, Australia, said, "I can talk with confidence about the situation on Coolmore, and over the last season we had less placentitis and abortion than in any of the past five years."

It was noted that there are similarities between EAFL and MRLS in that pathologists have found amnionitis and infection of the amniotic portion of the umbilical cord. However, there have been no widespread abortions throughout all the gestational stages in Australia as there were in the United States in 2001 and 2002. Some Australian veterinarians are reluctant to put a label on this problem at this time.

Perkins, who formerly was head of the epidemiology group at Massey University in New Zealand, went on to say, "Abortions occurred in mid to late pregnancy without any illness in the mare. The most consistent pathologic change has been inflammation of the amnion and amniotic portion of the umbilical cord, and variable changes have been observed in the fetus. Cases do not have significant involvement of the outer placental membrane (chorion). Bacteria cultured from affected fetuses have included a range of organisms that normally live in soil, on plants, and in water, and that are not typically considered to be the cause of disease in animals (isolates include Microbacterium spp, Cellulosimicrobium spp, Athrobacter spp, and Curtobacterium spp)."

Similar cases of mare abortion have been reported occasionally from farms in New South Wales over the past several years, added Perkins, including instances where small farms have had more than half of their pregnant mares abort.

Perkins noted that pathology records from 2004 indicated that EAFL accounted for up to one third of all abortions in the Hunter Valley in 2004 in cases where a fetus was found and submitted for post mortem.

About the Author

Kimberly S. Brown

Kimberly S. Brown was the Publisher/Editor of The Horse: Your Guide To Equine Health Care from June 2008 to March 2010, and she served in various positions at Blood-Horse Publications since 1980.

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