'One Health' investigation: outbreak of human Salmonella Braenderup infections traced to a mail-order hatchery - United States, 2012-2013

Abstract

Human salmonellosis linked to contact with live poultry is an increasing public health concern. In 2012, eight unrelated outbreaks of human salmonellosis linked to live poultry contact resulted in 517 illnesses. In July 2012, PulseNet, a national molecular surveillance network, reported a multistate cluster of a rare strain of Salmonella Braenderup infections which we investigated. We defined a case as infection with the outbreak strain, determined by pulsed-field gel electrophoresis, with illness onset from 25 July 2012-27 February 2013. Ill persons and mail-order hatchery (MOH) owners were interviewed using standardized questionnaires. Traceback and environmental investigations were conducted. We identified 48 cases in 24 states. Twenty-six (81%) of 32 ill persons reported live poultry contact in the week before illness; case-patients named 12 different MOHs from eight states. The investigation identified hatchery D as the ultimate poultry source. Sampling at hatchery D yielded the outbreak strain. Hatchery D improved sanitation procedures and pest control; subsequent sampling failed to yield Salmonella. This outbreak highlights the interconnectedness of humans, animals, and the environment and the importance of industry knowledge and involvement in solving complex outbreaks. Preventing these infections requires a 'One Health' approach that leverages expertise in human, animal, and environmental health.

Keywords: Outbreaks; Salmonella; Salmonella enterica; poultry; zoonoses.

Fig. 1.

Location and number of case-patients infected with the outbreak strain of Salmonella Braenderup, by state, July 2012–February 2013

Fig. 2.

Number of cases of human Salmonella Braenderup infections with the outbreak strain, by date of illness onset, United States, July 2012–February 2013

Fig. 3.

Traceback investigation: distribution from ultimate source hatchery to interviewed ill persons, United States, July 2012–February 2013. (Distribution chain flows from top to bottom. Hatchery D supplied poultry to or drop-shipped poultry for eight hatcheries: X, A, B, E, G, H, J, and L, and supplied poultry directly to eight feed stores: 2, 3, 4, 5, 6, 7, 8, and 12. Other hatcheries in turn supplied poultry to feed stores, and ill persons received poultry from hatcheries or feed stores, respectively. For example, hatchery B supplied poultry to feed store 1; hatcheries C, D, and E all supplied poultry to feed store 2, etc. Data were available for only 16/48 case-patients.)