The present invention relates to a non-human mammalian animal which has been modified to have in the blood, plasma and/or serum (a) an increased number of leukocytes and/or neutrophils, and (b) a reduced activity of the DNase 1 and/or DNase 1-like 3 enzymes. The non-human mammalian animal is particularly suitable for studying inflammation and/or a disease associated with inflammation. In a further aspect, the invention relates to the use of the non-human mammalian animal as a model for identifying therapeutic or diagnostic targets of inflammation and/or a disease associated with inflammation. In a still further aspect, the invention relates the use of the non-human mammalian animal as a model for drug candidate testing. In addition, a method for testing an anti-inflammatory drug candidate against extracellular DNA is provided. Finally, a method for testing an anti-inflammatory drug candidate for modifying the formation or degradation of neutrophil extracellular traps is provided. In still another aspect, the present invention relates to a non-human mammalian animal, which has been modified to have an increased number of neutrophils in blood.