Hemorrhagic Septicemia in Livestock: Molecular Insights, Epidemiological Dynamics, and Next-Generation Control Strategies

Hemorrhagic septicemia (HS), caused by Pasteurella multocida serotypes B:۲ and E:۲, remains one of the most destructive bacterial diseases of cattle and buffalo in tropical and subtropical regions. Its hyperacute course, high mortality, and recurring outbreaks impose major economic losses, particularly on smallholder farming systems, where food security and livelihoods are already fragile. Despite centuries of recognition, HS persists as a neglected threat due to its complex molecular pathogenesis, dynamic epidemiology, and the rapid rise of antimicrobial resistance (AMR). At the molecular level, P. multocida deploys adhesins, toxins, capsules, iron acquisition systems, and biofilm formation to evade host immunity and trigger systemic septicemia. Comparative genomics underscores substantial strain diversity, plasmid-mediated resistance genes, and virulence islands, which complicate therapeutic and vaccine development. Epidemiologically, HS is driven by geography, seasonal monsoon patterns, host susceptibility, and environmental reservoirs that maintain persistent transmission cycles. Conventional bacterin vaccines and antimicrobials, though historically central to control, often fail under field conditions, with resistance to sulfonamides, tetracyclines, macrolides, and β-lactams increasingly reported. Emerging strategies, including recombinant and DNA vaccines, live-attenuated and aerosolized platforms, and immunomodulatory approaches, show promise but remain insufficiently validated in endemic contexts. Parallel advances in multi-omics, precision livestock farming (PLF), and molecular surveillance provide new opportunities, yet face barriers such as infrastructure, cost, and regulatory inertia. This review consolidates current insights into HS pathogenesis, epidemiology, AMR, and vaccine development, while identifying critical gaps and research priorities. Its scope is to bridge molecular discoveries with field-level applications, offering a framework for sustainable HS control and mitigation of its global burden.

کلیدواژه ها:

Antimicrobial resistance (AMR) ، Hemorrhagic septicemia (HS) ، Molecular pathogenesis ، Multi-omics surveillance ، Pasteurella multocida B:۲ and E:۲ ، Vaccine breakthroughs