Haemorrhagic septicaemia
It is also known as septicemic pasteurellosis or barbone and the disease is clinically characterized by high fever, excessive salivation and petechial haemorrhages on submucosae.
Etiology: The disease is caused by Pasteurella multocida (capsulated Gram negative small coccoid rods) in cows, buffaloes, sheep, goat, camel, pigs and horses. The morbidity and mortality rates are high and untreated cases usually die. Disease is highly prevalent in tropical countries. In India, disease outbreaks occur in rainy season when animals are exposed to heavy work or stress of environment.
Clinical signs: In bovines, the disease occurs in acute form resulting in septicemia, hyperpyrexia, severe depression, profuse salivation and haemorrhages in the submucosae. The organisms are localized in the subcutaneous tissue and multiply there to develop hot, painful swelling around throat, dewlap, brisket and perineum. There is severe dyspnoea and death occurs as a result of respiratory distress. In less severe cases, animals suffer from pneumonia, diarrhoea or dysentery.The animals which die due to this disease reveal subcutaneous edema in head, neck and throat region, gelatinous infiltration around pharynx and larynx as well as swelling of adjacent lymph glands. Haemorrhages are noticed in subcutaneous and intermuscular tissues, lymph glands, peritoneum and pleura. The pericardium is usually covered with haemorrhagic spots. In the later cases, haemorrhagic gastroenteritis is commonly noticed.
Diagnosis: Clinical signs and postmortem examination of dead animals give excellent indication for diagnosis of the disease. Confirmed can be made by isolation of the organisms from saliva or blood. Animal inoculation test also helps in its detection. Suspected blood or saliva can be inoculated into mice and the inoculated mice die within 48 h. Serological tests like immunodiffusion and fluorescent antibody tests are of use for its confirmatory diagnosis.
The disease should be differentiated from anthrax, blackquarter and leptospirosis. In anthrax, there is escape of blood from natural openings. Crepitating swellings are present on muscular areas like shoulder in blackquarter (BQ). Leptospirosis is associated with haemoglobinuria, anaemia and liver infarcts.
Treatment: In severely affected animals, 100-200 ml of anti-haemorrhagic septicemia serum may be used. Half of its dose is given by intravenous route while half is given subcutaneously. Sulphadimidine is highly effective and has been used earlier as the drug of choice. It is given @ 150 to 200mg /kg body weight subcutaneously 3-4 days. The combination of trimethoprim and sulfamethroxazole is also highly effective and given @ 3-5 ml/50 kg body weight by intramuscular route for 4-5 days. Chloramphenicol (20 mg/kg body weight) or oxytetracycline (10 mg/kg body weight) are also effective when given intramuscularly once daily for 5-7 days. Other antibiotic such as norfloxacin, ciprofloxcin, ampicillin or amoxicillin may also be used for its treatment.
Control: Vaccines (2 types) are available against this disease - (i) oil-adjuvant vaccine, and (ii) alum precipitated vaccine. Oil-adjuvant vaccine is given @ 2 ml in animals weighing up to 150 kg, and 3 ml in animals above 150 kg. The vaccine is given by intramuscular route before onset of rainy season and it provides immunity for 1 year. Alum precipitated vaccine is used @ 5-10 ml subcutaneously and animals gets protection up to 6 months. A combined vaccine against HS and BQ is available which is given before onset of rains @ 5 ml by subcutaneous route. By adopting general hygienic measures, the occurrence of disease can be minimized