Natural Attenuated Vaccines for Pasteurella multocida.

Pasteurella multocida is capable of infecting various animal species, causing hemorrhagic septicemia or infectious pneumonia, and it is widely prevalent and pathogenic worldwide. However, the prevention and control technologies for animal pasteurellosis remain relatively under-developed, with a heavy reliance on the traditional inactivated vaccines and live attenuated vaccines developed in the mid-20th century. A previous systematic review summarized research progress in the field of inactivated vaccines for animal pasteurellosis and revealed that inactivated vaccines exhibit high levels of homologous protective efficacy, albeit with a relatively short duration of immunity and limited cross-protection between different serotypes. Live attenuated vaccines are known to exhibit significant advantages, including a prolonged duration of immunity, strong cross-protective capacity, and low production costs. Throughout the history of vaccine development, various live attenuated vaccines have been extensively used as critical tools for preventing and controlling infectious diseases in animals and humans and combating antimicrobial resistance, substantially reducing the morbidity and mortality rates of regional or international epidemics. The developmental history of live attenuated vaccines against Pasteurella multocida has primarily encompassed three distinct research and application periods, characterized by natural attenuated vaccines, traditional attenuated vaccines, and genetically engineered live attenuated vaccines. Here, we comprehensively review the research and application history of natural attenuated vaccines for Pasteurella multocida. Our aim was to provide theoretical foundations and novel perspectives for the development of a new generation of live attenuated vaccines against pasteurellosis in livestock and poultry.