Background: Haemorrhagic septicaemia (HS) is acute, highly contagious form of disease of water buffalo, cattle, and bison caused by Pasteurella multocida (PM). It is considered the most economically important bacterial disease of cattle and buffalo, .in tropical areas of Asia, particularly in Southeast Asia. PM is a gram-negative coccobacillus, belonging to Pasteurellaceae family. PM is transmitted either during direct contact or via fomites by ingestion or inhalation via contaminated feed and water. Currently, there are no broadly protective vaccines -adjuvant formulation with long-lasting immunity available against HS. Aluminium-based mineral salts such as alum are the only immunologic adjuvants. Herbal adjuvants are evaluated extensively to replace the classical adjuvants being safe and efficacious.Result: In the present study, one herbal adjuvant DIP-HIP is evaluated with inactivated PM (iPM) antigen as vaccine in both small (mice) as well as big (cattle) animals for its efficacy. The results suggest that after single booster DIP-HIP + iPM emulsion gave maximum antibody titres in comparison to iPM alone or Alum + iPM in both mice as well as seronegative cattle. To further confirm the potential of DIP-HIP adjuvant formulation with iPM antigen in providing protection against HS, the median lethal dose (LD 50 ) of PM was determined (1 X 10 7 CFU/ml), following which DIP-HIP + iPM emulsion immunized mice were challenged with this dose. The DIP-HIP containing formulation turned out to be broadly protective against HS with long-lasting immunity.
Conclusion:DIP-HIP is a potential adjuvant, which can be used in HS vaccines to provide extended immunity.The cattle are infected when they ingest or inhale the causative organism. Buffaloes have been found to be more vulnerable than cattle to HS with shorter course of disease and mortality reaching 100% if not treated at early stage [9]. The characteristic lesion of HS is swelling of the subcutis and muscle of the submandibular region, neck, and brisket by clear to blood-tinged edema fluid. Hemorrhages are often most prominent in the pharyngeal and cervical lymph nodes. The infected animals show typical symptoms of HS such as pyrexia, hypersalivation, nasal discharge, sudden drop of milk yield, abdominal pain, severe diarrhea and dysentry, rapid respiration and cyanotic mucus membrane before death [10]. Clinical diagnosis of HS in endemic areas is based on history, lapses in vaccination, environmental conditions, and the typical clinical signs while a definitive diagnosis of HS is based on isolation of PM serotype B:2 or E:2 (or other less common serotypes recognized by the OIE as causing HS) from the blood and tissues of an animal with above mentioned characteristic signs. The passive mouse protection test using specific B:2 and E:2 immune rabbit sera has been used in Asia and Africa to identify different serotypes of PM (The Merck Veterinary Manual).If administered very early in the disease, antimicrobials drugs such as sulfonamides, tetracyclines, penicillin, g...
