Salmonella Outbreaks and Prevention

What impact can a salmonella outbreak at a veterinary hospital and what can be done to prevent it? Magdalena Dunowska, DVM, PhD, postdoctoral fellow in the veterinary teaching hospital at Colorado State University (CSU), discussed this issue at the 50th annual American Association of Equine Practitioners (AAEP) Convention in Denver, Colo., Dec. 4-8, 2004. She told the group that the James L. Voss Veterinary Teaching Hospital at CSU was hit with salmonella outbreaks in 1996 and 2001. The 1996 outbreak, she said, resulted in the hospital being closed for three months. The cost to the university for the closure was $500,000.

Yet the losses were greater because the $500,000 only covered expenses of clearing the hospital of the bacteria and does not include losses from clientele who were not allowed to bring horses to the facility.

As part of a study to determine what could be done to cut down on the harmful bacteria, a footbath for workers was compared to disinfectant misting, she said. The ammonia-based solution in the footbath did little to alleviate the harmful bacteria, she said, but fogging the facility with 180 liters of 4% peroxygen disinfectant with backpack foggers did have a highly positive effect.

The peroxygen formula appears to be safe for animals, Dunowska said, but there have been no scientific tests authenticating that belief. Because of the lack of data, it is suggested that all animals be removed from the facility during the fogging procedure, she said.

Josie Traub-Dargatz, DVM, MS, Dipl. ACVIM, professor of clinical sciences at CSU, continued the discussion by evaluating hygiene protocols and the effect they had on reducing bacterial load on the hands of equine veterinary staff performing routine physical examinations. This study at CSU compared washing hands for 15 seconds with antibacterial soap, application of a 67% alcohol-based hand sanitizer, and using a chlorhexidine-alcohol lotion. Hand rinse samples were obtained before the physical examination, after the physical examination, and after the hand hygiene protocol.

The result: "Based on the reduction factor the alcohol-based sanitizer and the chlorhexidine-alcohol lotion reduced the bacterial load on hands after a physical examination more than washing hands for 15 seconds with antibacterial soap containing 0.3% triclosan," Traub-Dargatz said.

About the Author

Les Sellnow

Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at or by calling 800/582-5604.

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