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

Electrostatic space chargers were used to downstream ends of the cabinets. When chicks impart a negative charge to airborne dust particles and thereby cause them to be attracted to grounded surfaces. To determine whether nega tive air ionization could affect the airborne transmission of Salmonella en teritidis, chicks were housed in four controlled-environment isolation cabi nets in which airflow was directed across an unoccupied central area from o ne ("upstream") group of birds to another ("downstream") group. Negative ai r ionizers were installed in two of these cabinets. In three replicate tria ls, groups of chicks were placed in the upstream ends of the transmission c abinets and orally inoculated with S. enteritidis at 1 wk of age. On the fo llowing day, 1-d-old chicks were placed in the were sampled at 3 and 8 d po stinoculation, S. enteritidis was found on the surface of 89.6% of the down stream chicks from cabinets without negative air ionizers, but on only 39.6 % of the downstream chicks in the presence of the ionizers. Similarly, S. e nteritidis was recovered from the ceca of 53.1% of sampled downstream chick s 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 wa s also associated with reduced levels of circulating airborne dust particle s. Reducing airborne dust levels may thus offer an opportunity to Limit the spread of S. enteritidis infections throughout poultry flocks.