Application of negative air ionization for reducing experimental airborne transmission of Salmonella enteritidis to chicks.

Electrostatic space chargers were used to impart a negative charge to airborne dust particles and thereby cause them to be attracted to grounded surfaces. To determine whether negative air ionization could affect the airborne transmission of Salmonella enteritidis, chicks were housed in four controlled-environment isolation cabinets in which airflow was directed across an unoccupied central area from one ("upstream") group of birds to another ("downstream") group. Negative air ionizers were installed in two of these cabinets. In three replicate trials, groups of chicks were placed in the upstream ends of the transmission cabinets and orally inoculated with S. enteritidis at 1 wk of age. On the following day, 1-d-old chicks were placed in the downstream ends of the cabinets. When chicks were sampled at 3 and 8 d postinoculation, S. enteritidis was found on the surface of 89.6% of the downstream chicks from cabinets without negative air ionizers, but on only 39.6% of the downstream chicks in the presence of the ionizers. Similarly, S. enteritidis was recovered from the ceca of 53.1% of sampled downstream chicks in cabinets without ionizers, but from only 1.0% of the ceca of chicks in cabinets in which ionizers were installed. The presence of the ionizers was also associated with reduced levels of circulating airborne dust particles. Reducing airborne dust levels may thus offer an opportunity to limit the spread of S. enteritidis infections throughout poultry flocks.