Tolerance to infection can be illustrated via comparing host performance versus increasing load.
High tolerance is indicated as a flat slope, i.e., host performance is not influenced by increasing burden.
Steep downward slope indicates low tolerance in which host performance is strongly reduced with increasing burden.
Genetic variation in tolerance and its correlation with resistance, can be quantified using random regression model.
Research is complicated by the fact that animal protocols typically involve expecting some of the subjects to die, which is not ethical in humans.