|Van Kessel, Jo Ann|
Submitted to: Epidemiology and Infection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2007
Publication Date: 4/20/2007
Citation: Chapagain, P.P., Van Kessel, J.S., Karns, J.S., Wolfgang, D.R., Hovingh, E., Nelen, K., Schukken, Y.H., Grohn, Y.T. 2007. A mathematical model of the dynamics of Salmonella Cerro infection in a U.S. dairy herd. Epidemiology and Infection. Available: http://Journals.Cambridge.org. Interpretive Summary: Salmonella spp. are zoonotic pathogens that are frequently isolated from dairy cattle. As in people, salmonellosis (the clinical disease caused by Salmonella spp.) can have serious health implications in calves and cattle, but animals can harbor Salmonella without showing clinical signs of illness. We developed a mathematical model of the transmission dynamics of Salmonella to describe an outbreak of Salmonella Cerro infection that was monitored for one year in a Pennsylvania dairy herd. Understanding the dynamics of Salmonella transmission and carriage in dairy cattle is necessary for development of effective intervention strategies.
Technical Abstract: We developed a mathematical model of the transmission dynamics of Salmonella to describe an outbreak of S. Cerro infection that occurred in a Pennsylvania dairy herd. The data were collected as part of a cooperative research project between the Regional Dairy Quality Management Alliance and the Agricultural Research Service. After the initial detection of a high prevalence of S. Cerro infection in the herd, a frequent and intensive sampling was conducted and the outbreak was followed for one year. The data showed a persistent presence of S. Cerro with a high prevalence of infection in the herd. The dynamics of host and pathogen was modeled using a set of non-linear differential equations. A more realistically distributed (gamma distributed) infectious period using multiple stages of infection was considered. The basic reproduction number was calculated and relevance to the intervention strategies is discussed.