Anthrax is a zoonosis which is particularly prevalent in cattle, goats and sheep and is caused by Bacillus anthracis, a Gram-positive spore forming aerobic microorganism. The endospores can survive outside of the body for many decades. The natural form of anthrax has a cutaneous, pulmonary and intestinal form. The pulmonary form can be rapidly fatal but is difficult to recognise due to an initially non-specific, flu-like clinical picture. As a result of spores being inhaled, a mediastinal lymphadenitis arises from which a systemic disease develops with a violent toxaemia, damage to the vascular endothelium, oedema, internal haemorrhages and circulatory collapse. Anthrax is diagnosed by demonstrating the presence of the bacteria in the cutaneous abnormality, in blood or another sterile body component such as cerebrospinal fluid, by means of a direct preparation, immunofluorescence or surface antigens, molecular diagnostics with PCR, or by means of culturing. B. anthracis is sensitive to quinolones, clindamycin and tetracyclines, and often to penicillin. Although naturally acquired cutaneous anthrax can be effectively treated with a short antibiotic cure, it is nevertheless advised in the USA to complete the full 60-day cure and to regard the cutaneous manifestation as a telltale sign of possible respiratory exposure. Anthrax is not transmitted from one person to another.