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United States Department of Agriculture

Agricultural Research Service

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Research Project: Evaluation of Interventions Using a Novel, Transdermal Challenge Model

Location: Food and Feed Safety Research

Project Number: 6202-32000-030-64
Project Type: Reimbursable

Start Date: Nov 01, 2012
End Date: Dec 31, 2014

Objective:
Develop a precise and accurate estimation of duration of infection within the lymph nodes of cattle for various serotypes and subpopulations of Salmonella, an understanding of cellular tropism across various serotypes with and without interventions, and a rapid and well-controlled evaluation of candidate interventions designed to reduce the duration of infection within lymph nodes of cattle (particularly targeted to those subpopulations of Salmonella identified above).

Approach:
A multi-pronged inoculator (e.g., 10-lancet) allergy skin-testing device is inoculated with a Salmonella broth and applied with mild pressure to specific regions of the bovine's hide that are drained to region-specific lymph nodes. Different subtypes or serotypes of Salmonella can be applied to different regions of the animal. This process may be repeated at the time of initial inoculation or at subsequent days. At various time points after inoculation, the calves are sacrificed and the lymph nodes recovered and Salmonella presence can be determined or quantified using various methods. Various statistical approaches (such as survival analysis) can be performed to estimate duration of infection. Moreover, candidate interventions can be applied to a portion of the calves to evaluate any impact on the duration of infection within peripheral lymph nodes.

Last Modified: 9/22/2014
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