Related Experiment Video
Updated: Jul 1, 2026

Modified Most Probable Number Assay to Quantify Salmonella in Raw and Ready-to-Cook Chicken Products
Published on: January 31, 2025
The risk and control of Salmonella outbreaks in calf-raising operations: a mathematical modeling approach
Cristina Lanzas1, Lorin D Warnick, Renata Ivanek
1Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. cl272@cornell.edu
Abstract:
Salmonellosis in calves has economic and welfare implications, and serves as a potential source of human infections. Our objectives were to assess the risk of Salmonella spread following its introduction into a herd of pre-weaned calves and to evaluate the efficacy of control strategies to prevent and control outbreaks. To meet these objectives, we developed a model of Salmonella transmission within a pre-weaned group of calves based on a well documented outbreak of salmonellosis in a calf-raising operation and other literature. Intervention scenarios were evaluated in both deterministic and stochastic versions of the model. While the basic reproduction number (R0) was estimated to be 2.4, simulation analysis showed that more than 60% of the invasions failed after the introduction of a single index case. With repeated introduction of index cases, the probability of Salmonella spread was close to 1, and the tested control strategies were insufficient to prevent transmission within the group. The most effective strategies to control ongoing outbreaks were to completely close the rearing operation to incoming calves, to increase the proportion of admitted calves that were immunized (>75%), and to assign personnel and equipment to groups of calves.
Related Concept Videos
Steps in Outbreak Investigation
Investigation of Disease Outbreaks
Sources of Food Contamination
Hazard Analysis and Critical Control Points (HACCP)
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Mechanistic Models: Compartment Models in Algorithms for Numerical Problem Solving
In individual population analyses, different algorithms are employed, such as Cauchy's method, which uses a...
