Illuminated darkfield micrograph of Bacillus anthracis, a chained, spore forming bacteria that is the cause of anthrax. B. anthracis was the first bacterium identified as the cause of a disease. Symptoms vary depending upon the type of exposure. With skin exposure, swollen lymph glands, and a boil like lesion will appear. With respiratory exposure, symptoms resemble a common cold, progressing to severe breathing problems and shock. Inhalation of anthrax is usually fatal as its spores produce lethal toxins that rupture the alveoli in the lungs. Respiratory anthrax is a potential agent in biological warfare as the spores of the bacterium can be freeze-dried and disseminated as an aerosol or powder. Magnification: 1000x at 35mm.