Haemorrhagic septicaemia (HS) is a major disease of cattle and buffaloes characterised by an acute, highly fatal septicaemia with high morbidity and mortality. It is caused by certain serotypes of Pasteurella multocida that are geographically restricted to some areas of Asia, Africa, the Middle East and southern Europe. The disease has been recorded in wild mammals in several Asian and European countries. In many Asian countries disease outbreaks mostly occur during the climatic conditions typical of monsoon (high humidity and high temperatures). Pasteurella multocida, a Gram-negative coccobacillus, resides mostly as a commensal in the nasopharynx of animals. The Asian serotype B:2 and the African serotype E:2 (Carter and Heddleston system), corresponding to 6:B and 6:E (Namioka-Carter system), are mainly responsible for the disease. There are no confirmed reports of human infections with P. multocida B:2 and E:2; however, other serotypes do cause human infections and precautions should be taken to avoid exposure.