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Haemorrhagic septicaemia (HS) is a contagious bacterial disease caused by two serotypes of Pasteurella multocida, B2 and E2. It affects cattle (Bos taurus and B. indicus) and water buffaloes (Bubalus bubalis) with a high mortality rate in infected animals. It is regarded as one of the most serious diseases of large ruminants in south east Asia.
Classification
OIE List B disease
Susceptible species
The water buffalo is the most susceptible species, followed by cattle.
Distribution
HS occurs in South and South East Asia, the Middle East and most of Africa, the disease has also been reported to occur occasionally in Southern Europe. 
Clinical signs 
Most cases are acute or peracute. The following signs are seen:High feverDepressionReluctance to moveSalivation and nasal dischargePainful, oedematous swelling of the throat, extending to the brisketCongested mucous membranesRespiratory distressCalves may have a haemorrhagic gastro-enteritisDeath in 6-48 hours after onset of clinical signs. Recovery is rare.
Post-mortem findings 
Oedematous swellings of the throat-brisket contain a clear, straw-coloured serous fluidBlood-tinged fluid in body cavitiesPharyngeal and cervical lymph nodes are swollen and congestedSubserosal petechial haemorrhagesGeneralised congestion of the lungsVariable congestion of the abomasum and intestinal tractCalves may have haemorrhagic gastro-enteritisGross lesions will be minimal in animals that have died quickly.
Differential diagnosis 
BlacklegRinderpestAnthrax.
Specimens required for diagnosis 
The diagnosis is base on the isolation of Pasteurella multocida.Heparinized blood from live animals or affected tissue from fresh post-mortem should be collected aseptically. Samples should be kept cool and shipped on wet ice as soon as possible. Swabs in transport media, ribs, and tips of ears are sometimes submitted from remote areas in developing countries.
Transmission   
HS is principally a disease of animals under stress. In endemic areas about 2% of healthy cattle and buffalo carry the organism in lymphatic tissue of the upper respiratory tract. Intermittently, even in the presence of circulating antibody, the organisms invade the nasopharynx and are excreted in nasal secretions. These episodes may be triggered by stress. Infection is transmitted by:Direct contact between animalsContaminated feedstuffs or waterThe bacterium does not survive in the environment for more than a few days.
Risk of introduction   
Because the organism survives poorly outside the host, it is unlikely that it would be introduced to a new area except by the introduction of live animals. N.B. healthy animals can carry the organism. Restriction of imports of live animals from endemically infected countries, would keep the risk of introduction low.
Control / vaccines  
In endemically infected areas, annual immunisation using adjuvant vaccines gives good control. Whether HS can be eradicated from an area by comprehensive vaccination campaigns is unclear.
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