glanders as a zoonosis: focused on epidemiology, diagnosis, and vaccine development of a global veterinary and medical biothreat

Burkholderia mallei is the etiological agent of glanders, a disease of significant animal and human health concern. this organism is a gram-negative, non-motile, non-flagellated, non-spore-forming, non-encapsulated, aerobic, and facultative intracellular rod bacterium. glanders can be lethal and is highly contagious, so it is always nominated as a biothreat agent. here, we tried to cover nearly all aspects of the disease. these include the description of the agent, disease transmission, epidemiology, prevalence, the status of the disease, and ongoing eradication programs in eurasia. economic importance, pathogenesis, pathology, human cases, diagnosis, differential diagnosis, treatment, antimicrobial capabilities of this agent against other pathogenic species of microorganisms, and ways to control the disease have also been discussed. finally, vaccine development strategies and possible vaccine types that have been evaluated against this disease are the most detailed parts. conclusively, we did a thorough literature review from the 1980s to 2024. from an epidemiologic perspective, glanders has been eradicated from most of the western european countries. in contrast, developing areas of the world are still struggling with this organism. the disease mainly affects horses, donkeys, and mules and can be transmitted to people by close contact with glanderous animals. two newly published case reports from iran and türkiye in 2023 and 2024 described cases of human glanders. a beneficial point regarding the diagnosis in equids is that recent studies reported the development of the rose bengal test to make the diagnosis of glanders easier in the first steps of monitoring. there is no specific therapy or vaccine commercially available for animals or humans. the authors anticipate that on top of every platform potential for vaccine development, live-attenuated vaccines play a leading role in the future of glanders prevention. therefore, an integrated veterinary and medical collaboration must occur to control the incidence and re-emergence of the disease.