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Campylobacter Vaccine for Poultry Targets Human Foodborne Illness
By moniquegarcia on Tue, 09/03/2013 - 10:20am
Most people are familiar with Salmonella and its potential to make people ill. But few know about Campylobacter jejuni, even though it competes yearly with Salmonella in making people sick. Campylobacter is one of the main causes of bacterial foodborne disease in the United States and worldwide. Raw chicken is one of the most common carriers of the bacteria. In the U.S. alone, 2.4 million cases are reported annually, with costs exceeding $1 billion. Americans consumed 86 pounds of chicken per person in 2006, the most recent numbers available.
Description of Action:
Funded by the USDA, faculty and graduate students in the UA Department of Veterinary Science and Microbiology have developed a new poultry vaccine using an attenuated strain of Salmonella to express Campylobacter proteins in chick intestines. The vaccine induces the chicks to make antibodies against Campylobacter, resulting in lower Campylobacter carriage in poultry, ultimately less Campylobacter transferred to humans and therefore significantly fewer foodborne illnesses. The vaccination process is simple, easy to produce and protective to the chick. The Salmonella is engineered to live long enough to stimulate antibody production, but dies before the chicks are harvested. Chickens need to be vaccinated early because they become infected at just two to three weeks of age. The goal is to halt the contamination before it spreads and survives on raw chicken sold in stores. The vaccine may be publicly available in two to three years.
The researchers are also refining the delivery method for the vaccine and are currently testing other Campylobacter genes in the Salmonella vector strain. They are searching for two or three genes that can be incorporated into the vaccine to express Campylobacter to a degree that will prevent colonization completely.
Ongoing research trials show the vaccine has significantly reduced the pathogen’s ability to colonize young chickens’ intestines. Preliminary studies indicate that Campylobacter infection was reduced by 99.9 percent compared with a control group: 4.4 million Campylobacter organisms were present in non-vaccinated birds, compared to 5,220 organisms in the vaccinated birds. At least 500 organisms are needed to produce the disease in humans, but the chlorine in the packinghouse chillers usually reduces bacteria by 1,000 to 100,000 organisms. Vaccinated chickens should be free of Campylobacter after processing, according to the researchers who are refining the vaccine. The vaccine’s effect could be significant, as the U.S. poultry industry is the world’s largest producer of poultry meat: about 8.9 billion broilers go to market annually in the U.S., with a value of $21.5 billion. Europe has similar broiler production figures. The vaccine would serve as an intervention method for Campylobacter when the USDA mandates reduced numbers of food-borne pathogens in chicken, most likely in the next few years.