A new study by researchers at the Johns Hopkins Bloomberg School of Public Health examines the potential influence that the business connections between broiler chicken growers may have on the transmission of avian influenza, H5N1. According to the study, the risk of between-farm transmission is significantly greater among farms within the same company group than it is between farms with different company affiliation. The study is among the first to analyze the impact of company affiliation on the spread of diseases from farm to farm and it appears in the March 26 edition of PLoS One.
In 2007, U.S. growers produced more than 9 billion broiler chickens, according to a Department of Agriculture census. The poultry industry is vertically integrated with poultry companies contracting with growers to produce chickens for slaughter. These broiler chickens are grown in confined housing with defined feed in order to produce uniform and reliable meat.
"Our analysis indicates that company affiliation is a major driver of farm-based exposure risk to an infection like avian influenza in regions with high-density food animal production. Farms within the same integrator group as an infected farm may face as much as a five-fold increase in exposure risk compared to farms affiliated with a different group," said Jessica Leibler, a doctoral candidate in the Bloomberg School's Sommer Scholars program.
For the study, the Johns Hopkins researchers conducted a nationwide survey of broiler poultry growers to gather information on business practices and determine who visited the farm and how often. Typical contacts included farm workers, feed distributors, waste handlers and social contacts. The data from the survey were used to develop a model to approximate the nature and frequency of contact patterns among poultry farmers. The researchers used the model to analyze how an outbreak of H5N1 at a single farm on the Delaware-Maryland peninsula might spread
|Contact: Tim Parsons|
Johns Hopkins University Bloomberg School of Public Health