Poorly fed cattle are at greater risk of carrying dangerous levels of E. coli 0157:H7 bacteria, the food-borne pathogen that killed four children who ate undercooked hamburgers on the West Coast in early 1993. That's the finding of ARS researchers looking at cost-effective ways to reduce meat animal exposure to the deadly bacteria. Cattle subjected to dietary stress during shipment to market represent a high-risk group. Fasting animals have an imbalance of rumen microorganisms that normally keep the bad bugs at bay. The scientists' recommendation: Producers and marketers should feed cattle being sent to market regularly to maintain the normal balance of rumen microbes and suppress pathogenic bacteria like E. coli 0157:H7.
Physiopathology Research, Ames, IA
Mark Rasmussen/Brad Bosworth, (515) 239-8242

Spraying newly hatched broiler chicks with a blend of bacteria from mature chickens' intestines helps the chicks fend off Salmonella infection. In laboratory tests, researchers fed the blend, CF-3, to day-old broiler chicks. The next day, they fed each chick 10,000 Salmonella typhimurium bacteria. Ten days later, the chicks' intestinal levels of Salmonella were 99.9 percent lower than in untreated birds. CF-3 also protects chicks in tests at commercial poultry houses. Older broilers have higher intestinal levels of volatile fatty acids, such as propionic acid, that don't kill Salmonella, but do inhibit its growth. A newly hatched chick normally does not have enough volatile fatty acids to stymie Salmonella, but chicks treated with CF-3 have about the same ability to ward off Salmonella as a 21-day-old chicken. Natural mixtures such as CF-3 could lessen the now-common addition of antibiotics to poultry feed.
Food Animal Protection Research Laboratory, College Station, TX
Donald E. Corrier, (409) 260-9342

A parasite first found in dogs could be causing up to half of all cattle abortions, a problem that costs dairy producers in California alone about $35 million annually. Discovered and named by ARS researchers, the parasite--Neospora caninum--was implicated in about 50 percent of cattle abortions in a university study of approximately 700 dead calf fetuses. The ARS researchers are developing a test to detect the parasite in cattle. They aren't sure how the parasite is transmitted to livestock, but suspect wild carnivores such as coyotes eat an animal infected with the parasite, then pass the parasite in feces to contaminate livestock feed. Their recommendation to producers: Keep feed supplies covered so carnivores can't get in them. N. caninum has been identified in livestock all across the United States as well as Africa, Australia, Europe, Israel, Japan and New Zealand.
Parasite Biology and Epidemiology Laboratory, Beltsville, MD
J.P. Dubey, (301) 504-8128

A pond-side test that "borrows" a fragment of the disease-causing bacterium Edwardsiella ictaluri reveals within 30 minutes whether the bacterium is infecting the pond's fish. E. ictaluri strikes swiftly and kills up to 50 percent of fish. The ARS-developed kit detects bacteria early, while fish are still healthy enough to eat medicated feed. The kit contains an antigen from the bacterium's surface. Blood of infected fish will contain antibodies against the bacterium; a few drops of a fish's blood are all that's needed to disclose a link between the tell-tale antibodies and the test-kit antigen. DiagXotics, Inc. of Wilton, CT, will receive a patent license from ARS to commercialize the test kit and expects to market it by late 1996. (PATENT 5,238,824)
Fish Diseases and Parasites Research Laboratory, Auburn, AL
Phillip H. Klesius, (205) 887-4526