The causes of inflammation are of two main types: infectious and non-infectious factors: infectious factors include viruses, bacteria, rickettsiae, protozoa, fungi, mycoplasma, chlamydia, spirochetes, parasites and other infections. Non-infectious factors are severe trauma, burns, and major surgeries after which the body stresses the immune response, leading to inflammation. Exposure to ultraviolet light, radiation, or chemicals such as aromatics can also lead to inflammation. In addition, abnormalities in the body’s immune response, such as an overactive immune response, can cause tissue damage and lead to inflammation.