tailieunhanh - Báo cáo sinh học: "Effectiveness analysis of resistance and tolerance to infection"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học quốc tế đề tài: Effectiveness analysis of resistance and tolerance to infection | Detilleux Genetics Selection Evolution 2011 43 9 http content 43 1 9 GSE Ge n et i cs Selection Evolution RESEARCH Open Access Effectiveness analysis of resistance and tolerance to infection Johann C Detilleux Abstract Background Tolerance and resistance provide animals with two distinct strategies to fight infectious pathogens and may exhibit different evolutionary dynamics. However few studies have investigated these mechanisms in the case of animal diseases under commercial constraints. Methods The paper proposes a method to simultaneously describe 1 the dynamics of transmission of a contagious pathogen between animals 2 the growth and death of the pathogen within infected hosts and 3 the effects on their performances. The effectiveness of increasing individual levels of tolerance and resistance is evaluated by the number of infected animals and the performance at the population level. Results The model is applied to a particular set of parameters and different combinations of values. Given these imputed values it is shown that higher levels of individual tolerance should be more effective than increased levels of resistance in commercial populations. As a practical example a method is proposed to measure levels of animal tolerance to bovine mastitis. Conclusions The model provides a general framework and some tools to maximize health and performances of a population under infection. Limits and assumptions of the model are clearly identified so it can be improved for different epidemiological settings. Background The breeding objective in most livestock species is to increase profit by improving performance efficiency. One way to reach this objective is to improve the animals health for example through the implementation of appropriate management methods . chemotherapy vaccination and control of disease vectors . A more sustainable method consists in taking advantage by selective breeding of the within-breed variation that exists in the .