Pulmonary anthrax, coloured chest X-ray. Pulmonary anthrax is caused by the inhalation of spores (resistant reproductive cells) of the bacterium Bacillus anthracis. In this patient the bacteria have destroyed tissue in the cavity between the lung (the mediastinum, white), making it appear wider than normal. The bacteria have also spread to the lining of the chest cavity and caused the accumulation of liquid in the cavity (pleural effusion, bottom right). Pulmonary anthrax is almost always fatal. It starts with flu-like symptoms but quickly progresses to severe difficulty breathing, shock and coma. If caught at the very early stages it may be treated with antibiotics.