Business connection could increase risk of bird flu transmission

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 bird flu.

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 affiliated with different companies.

The study, which appears in the March 26 edition of PLoS One, is among the first to analyse the impact of company affiliation on the spread of diseases from farm to farm.

In 2007, US growers produced more than 9 billion broiler chickens, according to a USDA census. The poultry industry is vertically integrated with companies contracting with growers to produce chickens for slaughter. These chickens are grown in confined housing with defined feed in order to produce uniform and reliable meat.

According to the researchers, farms within the same integrator group as an infected farm may face as much as a fivefold increase in exposure risk compared to farms affiliated with a different group.

For the study, the Johns Hopkins researchers conducted a nationwide survey of broiler-poultry growers to gather information on business practices and to determine who visited the farm and how often.

The researchers used the model to analyse how an outbreak of H5N1 at a single farm on the Delaware-Maryland peninsula might spread through the poultry farm–dense region.

The research was funded by the Johns Hopkins Center for a Livable Future and the Sommer Scholars program at the Bloomberg School. Marco Carone, a doctoral candidate in the Bloomberg School’s Department of Biostatistics, also contributed to the article.