Evaluation of interventions using a novel, transdermal challenge model

Recipient Organization
AGRICULTURAL RESEARCH SERVICE
(N/A)
COLLEGE STATION,TX 77845

Performing Department
(N/A)

Non Technical Summary
(N/A)

Animal Health Component

40%

Research Effort Categories

Basic

50%

Applied

40%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
712	3310	1100	100%

Knowledge Area
712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins;

Subject Of Investigation
3310 - Beef cattle, live animal;

Field Of Science
1100 - Bacteriology;

Keywords

Goals / Objectives
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).

Project Methods
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.

Progress 10/01/12 to 09/30/13

Outputs
Progress Report Objectives (from AD-416): 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 (from AD-416): 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. This is a new project, with the goal of evaluating potential interventions (e.g., vaccines) for prevention of Salmonella uptake by, or to enhance Salmonella elimination from infected peripheral lymph nodes in, cattle. Work in FY 2013 focused on protocol development and implementation of initial studies which demonstrated some success in the use of vaccines to prevent Salmonella uptake by the lymph nodes. Subsequent research by this project will assess new experimental vaccines as well as other potential interventions. As work under this project progresses, important new information will be generated that will not only yield insight on how to control this important food safety pathogen, but will also increase our understanding of Salmonella uptake and elimination from the lymph nodes of cattle.

Impacts
(N/A)

Publications