|Gray, J - USDA, ARS, NADC|
Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: March 13, 1996
Publication Date: N/A
Technical Abstract: We produced soluble antigen extracts for the development of indirect ELISA assay which may be used to monitor the immune response and identify carrier animals. A mixed ELISA format, designated SalAD, was developed. The sensitivity and specificity of the test is >95% and >85%, respectively. The survival and transmission of Salmonella choleraesuis was investigated. Feces was collected from swine infected with Salmonella choleraesuis and was stored in either a dried or wet form. Bacterial survival was significantly longer in feces that had been dried. Swine also became infected following challenge by intranasal inoculation with dried feces. These data indicate that appropriate sanitation measures are critical when designing control plans in swine units and that any dried organic matter may serve as a reservoir for Salmonella. A survey of Salmonella in feed transport trucks was also conducted. Twenty-five culture swabs were taken from 22 trucks from 3 states; feed samples were also cultured from 17/22 trucks. Results indicate that 5/22 (22.7%) of the trucks were positive for Salmonella spp. and the sample prevalence was 0.7%. Three trucks had positive swabs (13.6%) and 4/22 feed samples (18.1%) were positive. More samples were positive from trucks containing meat, bone, or fishmeal than those containing vegetable-based feed which correlates with an FDA report. These data indicate that while the sample prevalence of Salmonella in feed trucks is low (0.7%) the overall contamination rate for feed trucks is much higher (22.7%). Additionally, it may be important to monitor levels of Salmonella in feed transport trucks and devise methods for sanitizing between loads. Additional work focused on the carrier state and use of segregated early weaning to reduce/eliminate Salmonella spp.