By Thom Sanders
The spies, brothers Anton and Carl Dilger, were culturing glanders and anthrax. Both of these deadly pathogens are zoonotic, diseases that can be transferred from animals to humans. Once produced, the cultures were passed to German saboteurs who infiltrated nearby ports to infect horses and mules bound for Allied forces in Europe.
Today, in 2018, Dr. Apichai Tuanyok, Assistant Professor in ID&I, is running quite a different laboratory with quite a different goal. Housed in the University of Florida’s Emerging Pathogens Institute, Dr. Tuanyok’s lab is trying to disarm glanders once and for all.
Although glanders has been eradicated from North America, the pathogen still looms as a possible threat. It might not be a household name like anthrax, but glanders is categorized similarly by the CDC. As Dr. Tuanyok notes, the underlying pathogen, Burkholderia mallei, is “classified as a Tier 1 (top tier) Select Agent,” meaning that the disease has significant biowarfare potential.
Dr. Tuanyok serves as the corresponding author on a recent paper published in Vaccines outlining early steps towards a safe and effective glanders vaccine. Using biosafe bacterial strains—strains that are genetically similar to glanders but non-pathogenic to humans—Dr. Tuanyok and his fellow researchers were able to create a vaccine that prevented lethal glanders in mice.
The researchers induced the biosafe surrogate bacteria to produce outer membrane vesicles (OMVs). Although these OMVs cannot cause infections, they contain antigens, molecules that can prompt immune reactions. Using the OMVs and their associated antigens, the researchers were able to create a vaccine that induced protective immunity in mouse subjects.
As the paper points out, a vaccine produced from both biosafe surrogates and OMVs has significant safety advantages over other options. Because the bacterial strains used to produce the vaccine are not considered human pathogens, it is unlikely that the resulting vaccine would pose a threat to humans. In other studies, researchers have produced vaccines that protected mice from glanders, but the types of vaccines used presented too much of a safety concern to proceed to human testing.
Humans have recognized the threat posed by glanders for thousands of years. As the authors of the paper remind us, both Hippocrates and Aristotle referenced the effects of the disease.
Unfortunately, the pathogen remains and may be re-emerging. In addition to concerns related to biowarfare, glanders could be re-establishing itself as a more conventional pathogenic threat due to the global movement of livestock.
If their research leads to a human vaccine, Dr. Tuanyok and his fellow researchers will have neutralized a disease that has plagued humans for millennia. In the meantime, Dr. Tuanyok says, “research towards vaccine development for glanders is a top priority.”
Readers can follow Dr. Tuanyok’s work and recent publications by visiting his faculty page. More information about glanders can be found on the CDC’s glanders web-page, and further information about the use of pathogens as weapons in WWI can be found at the National Archives. Visit the Emerging Pathogen Institute web-page for more on their important work.