A review of hemorrhagic septicemia in cattle and buffalo.

Hemorrhagic septicemia (HS), an acute, fatal and septicemic disease of cattle and buffaloes caused by Pasteurella multocida, is important in tropical regions of the world, especially in African and Asian countries. The prevalence of disease has been well documented with predominant isolation of P. multocida serotypes B:2 and E:2. Conventional methods of identification such as serotyping, biotyping, antibiogram determination and pathogenicity as well as molecular methods (P. multocida-specific polymerase chain reaction (PCR), a serogroup B-specific PCR assay, multiplex capsular typing system and loop-mediated isothermal amplification techniques) and characterization (restriction endonuclease analysis, randomly amplified polymorphic DNA analysis, repetitive extragenic palidromic PCR and enterobacterial repetitive intergenic consensus PCR analysis) are applied in parallel for rapid epidemiological investigations of HS outbreaks. Although several vaccine formulations including alum precipitated, oil adjuvant and multiple emulsion vaccines are commercially available, the quest for suitable broadly protective HS vaccines with long-lasting immunity is on the upsurge. Concurrently, attempts are being made to unravel the mysteries of the pathogen and its virulence factors, pathogenesis and determinants of protective immunity as well as diversity among strains of P. multocida. This review highlights the advances in these various aspects of HS.