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Genetic Test Pinpoints New Swine Diarrhea

In Iowa and Australia, pig producers have been talking about a new bacterium that causes watery diarrhea in pigs.

Although the diarrhea it produces doesn't cause bloody stools like swine dysentery does, it still weakens the pigs, slows their growth, and does a number on producers’ potential profits.

Until now, this bacterium resembling Serpulina hyodysenteriae--the causative agent of swine dysentery--hasn't had a name. Agricultural Research Service microbiologists Neil S. Jensen and Thad B. Stanton changed that when they cracked its genetic code and developed a DNA-based test to identify it.

Naming bacteria isn't new to Jensen and Stanton. They changed the name of Treponema hyodysenteriae to Serpulina hyodysenteriae in 1994, to more accurately describe that serpent-shaped bacterium.

More recently, the use of electronic mail opened up a global laboratory for Jensen and Stanton. No longer confined to their lab module at ARS’ National Animal Disease Center (NADC) in Ames, Iowa, the two researchers connected with Australian collaborators from Murdoch University in Perth.

That’s how Australian graduate student Darren J. Trott came to work in Stanton’s laboratory and to coin the name for the puzzling new bacterium: Serpulina pilosicoli. The name was reported in the January 1996 issue of the International Journal of Systematic Bacteriology, published by the American Society for Microbiology.

“It’s exciting to name a bacterium,” says Stanton.

“Once something has a name, everyone wants to talk about it. S. pilosicoli has been identified in about half of the recent samples we've checked from diseased pigs with spirochetal diarrhea in Iowa, and there’s a real need to determine the economic significance of this disease.”

Jensen’s DNA-based test distinguishes between S. pilosicoli and similar bacteria. It is being used at NADC to assist lab clinicians at Iowa State University’s Veterinary Diagnostic Laboratory. Farmers and veterinarians send fecal samples to the ISU laboratory in hopes of identifying the cause of intestinal disease in their pigs.— By Linda Cooke, ARS.

Thad B. Stanton is in the USDA-ARS Pre-Harvest Food Safety and Enteric Diseases Unit, National Animal Disease Center, Ames, IA; phone (515) 663-7495, fax (515) 663-7458.