Are Wildlife A Source Of Lawsonia?
Lawsonia intracellularis is a bacterium that causes an intestinal disease called proliferative enteropathy in young horses. One of the reasons we still don't know a lot about this disease is that this bacterium can't be grown in a lab. One of the areas in which researchers are working to find more information is from where horses that become sick initially get Lawsonia... Is it from healthy horses that are carriers? Does it circulate in the horse population, or is there an outside source? Does it come from pigs (pigs can also be affected by disease due to Lawsonia infection)? Do other animal species such as wildlife carry it?
A recent study by researchers at the University of California (Davis), published in the Journal of Wildlife Diseases (2008 44:992-998), looked at the presence of Lawsonia in wildlife on horse farms. They found DNA from the bacterium in feces from jackrabbits, striped skunks, Virginian opossums, and coyotes, but not from feral cats, Brewer's Blackbirds, raccoons, or ground squirrels.
This study provides some interesting insights about Lawsonia in horses, and raises the possibility that wildlife could be a source of infection. However, it does not tell us how to prevent the disease or whether wildlife really are a relevant issue when it comes to infecting horses. We certainly do NOT recommend trying to eradicate wildlife in the vicinity of horse farms as a Lawsonia prevention tool. However, making horse barns (especially feed storage areas) less inviting to wildlife is a good idea - this is a sound standard infection control measure that everyone should consider, as it may reduce the risk of several infectious diseases (e.g. equine protozoal myeloencephalitis (EPM)).
More information on Lawsonia can be found on the equIDblog Resources page, and in our earlier post entitled "Lawsonia intracellularis - New Horizons".
