Solving an avian scourge could also provide benefits to human health

The old adage ‘a bird in hand is worth two in the bush’ may very well apply to a new vaccine project underway in the lab of ASU School of Life Sciences Professor Roy Curtiss, director of the Center for Infectious Diseases and Vaccinology at the Biodesign Institute.

There, associate research scientist Melha Mellata is leading a USDA funded project to identify targets to develop a vaccine against a leading poultry disease, called avian pathogenic E. coli (APEC).

Mellata is an expert on understanding the genetic signposts of how certain kinds of E. coli turn deadly. “We have to understand how bacteria cause disease so that we can know the best way to fight them,” said Mellata.

According to the USDA, the two most common types of poultry infections are from the bacteria E. coli and Salmonella. Unlike in people, Salmonella is completely harmless to chickens.

But by attempting to solve the poultry scourge of APEC, Mellata and Curtiss are hopeful their ‘bird in hand’ project could ultimately provide a boost to protecting people against Salmonella, the leading cause of food-borne illness.

“What if you could get one vaccine to fight against a group of bacteria?” said Mellata. “We came up with a project where we would protect chickens, not only from E. coli infection but also Salmonella, and in doing so, improve human health.”

The U.S. has the leading poultry industry in the world, with an annual value of more than $50 billion and a poultry production forecast to continue its upward trend. E. coli infections are a big threat for the industry. The economic losses due to E. coli infections in broiler chickens were estimated to be more than $80 million in 2002.

Now, there is also considerable concern in the scientific community that APEC strains could become an emergent food pathogen. The poultry products are also a suspected source of a suite of infections called ExPEC (extra-intestinal pathogenic E. coli, which includes APEC), which have been associated with illnesses such as urethral infections, sepsis and meningitis.

Another human health ramification comes from work done by several research groups that have demonstrated that the poultry disease is also similar to other harmful E. coli, including the dreaded E. coli (O157:H7), which is responsible for human illness and death, typically from eating contaminated meat.

Antibiotics have long been the first line of defense to prevent APEC, but have lost their potency, as the bacteria have grown increasingly resistant to treatment.

“It’s becoming increasingly important to develop a vaccine to prevent bacterial infection in poultry,” said Mellata. “Poultry is not only a daily food staple, but less commonly known, also a key to human health. For example, the entire supply of flu vaccine production is made from eggs.”

Bacterial contamination resulted in half the U.S. flu vaccine supply being destroyed in 2004.