Editor’s note: This article is part of TheHorse.com’s ongoing coverage of topics presented at the 2012 American College of Veterinary Internal Medicine Forum, held May 30 – June 2 in New Orleans, La.

Although it’s not prevalent in all corners of the nation, Potomac horse fever (PHF) can be scary when it hits. Veterinarians are still working to fully understand the disease, which is caused by the bacteria Neorickettsia risticii. The collective understanding of this disease took a step forward when a team of researchers identified several factors associated with survival in affected horses.

Sandra Taylor, DVM, PhD, assistant professor of large animal medicine at the Purdue University College of Veterinary Medicine, discussed factors identified as being associated with surviving PHF at the 2012 American College of Veterinary Internal Medicine Forum, held May 30 – June 2 in New Orleans, La.

Taylor explained that PHF, which has a fatality rate approaching 30%, causes colitis (inflammation of the colon) and sometimes laminitis. She noted that “there are many different strains of the bacteria, so immunity against one strain does not always protect against infection with another strain