Human contacts and potential pathways of disease introduction on Georgia poultry farms

As highly pathogenic avian influenza H5N1 virus continues to circulate in the world, poultry farm biosecurity and timely reporting of morbidity and mortality among commercial poultry farms in the United States are major concerns. To assess the vulnerability of poultry farms to the introduction and spread of a highly infectious pathogen, such as the currently circulating H5N1 influenza virus, a survey was administered to growers in two counties in Georgia representing areas of low and high poultry densities. Survey questions regarding horizontal contacts and management were sent to commercial broiler and breeder-layer chicken producers. Responses were used to estimate and compare contact rates and patterns between the two regions. The distribution of high-risk visitors (i.e., those going inside the poultry houses) to poultry farms did not vary significantly between growers in counties with high and low poultry densities or between breeder-layer and broiler growers. Compared with broiler producers in the county with high poultry density, broiler growers in the county with low poultry density were more likely to hire non-family employees to help with poultry management (62% vs. 17%; P = 0.001) and assist other growers with their poultry (31% vs. 6%; P = 0.025). Use of contracted litter services was significantly higher (P = 0.019) among broiler growers in the poultry-dense county (40%) compared with the low-density county (6%). Compared with broiler growers, breeder-layer producers also were significantly more likely to hire non-family employees to help on the farm (53% vs. 17%; P = 0.008). Poultry growers in the highly poultry-dense county were more likely to have a public road or field receiving poultry litter within a quarter mile of their poultry houses, compared with those in the lower density county. Data obtained in this study support the observations of published poultry disease outbreak investigations and highlight the differences in farm vulnerability to disease introduction within areas of different poultry densities and management practices.