Diagnosis of haemorrhagic septicaemia: Past, present and future

Haemorrhagic septicaemia (HS) is a distinct bacterial disease of cattle and buffaloes, and is of economic importance in some parts of world including India. The causal agent of the deadly disease is Pasteurella multocida (serotype B:2 in Asia and E:2 in Africa). Accurate laboratory diagnosis and subsequent characterization (typing) of the causative organism by traditional methods are time consuming, laborious, costly and sometime provide ambiguous results. The development of DNA-based techniques has provided an alternative methods of detection and characterization that overcome the limitations of traditional methods. Two polymerases chain reaction (PCR) tests have been reported for detection of P. multocida. Both tests show promising and encouraging outcome as diagnostic tool. Till date, there have been various techniques used for typing of P. multocida isolates which include: restriction endonuclease analysis (REA), ribotyping, pulse field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) assay, repetitive extragenic palindromic–PCR (REP–PCR), multilocus enzyme electrophoresis (MLEE), amplified fragment length polymorphism (AFLP) and multi-locus sequence typing (MLST). All the new generation techniques are having certain limitations and constraints. These techniques are not suitable at all for isolation and are best used in parallel with other conventional techniques. At least two distinctly different methods should be used to give any inference.