HONOLULU (KHON2) — Researchers at the University of Hawaii at Manoa’s School of Life Sciences were awarded a $3-million contract from the U.S. Department of Defense to create a vaccine against a disease UH says is one of the most misdiagnosed and deadliest in the world.
Melioidosis, also called Whitmore’s disease, is an infectious disease caused by the Burkholderia pseudomallei bacterium. The illness has a 50% mortality rate and is commonly found in numerous tropical countries located 30 degrees latitude north and south of the equator, where the disease is considered endemic.
With a wide range of symptoms that can be mistaken for staph infections or diseases such as tuberculosis, Melioidosis is listed as a tier 1 select agent by the Centers for Disease Control and Prevention (CDC). That same list also includes anthrax and Ebola because of the biological agents and toxins involved.
“The threat to the military and civilian population is real in case of bioterrorism and biowarfare events,” said UH Manoa Professor Tung Hoang, who is leading the team of researchers. “We also send our servicemen and women into harm’s way stationed in endemic countries where they could be exposed to the bacterium and the disease. Of course, they need protection. Likewise with travelers, traveling to endemic countries.”
The disease skyrocketed during the Vietnam War, killing hundreds of soldiers. Helicopters landing in Vietnam propelled bacterial laden particles, which were buried in the sand and soil. Soldiers inhaled them, were misdiagnosed with pneumonia or tuberculosis, and died of melioidosis.
And according to the researchers, the disease isn’t just a threat to affected countries. People can become infected through cuts in their skin or by consuming contaminated water or inhaling particles containing the bacterium. Domesticated and farm animals can also get the disease, but experts say transmission between animals and humans is rare or hard to document.
Yun Heacock-Kang, a junior researcher with the School of Life Sciences, said while the disease itself has not been confirmed in Hawaii, the islands lies approximately 20 degrees north of the equator, making it a prime area for the bacteria to live.
“Because they reside in soil, if you have an importation of soil of potted plants between countries when it wasn’t well regulated, that could be a way for the bacteria to be transmitted,” Heacock-Kang said. “If people go hiking, they could have soil stuck on the sole of their boots, that could be carried around. Travelers have been diagnosed with Burkholderia pseudomallei infection in Hawaii, although that was linked to the travel history, not local infections.”
UH researchers have already spent more than 10 years studying the bacterium. They discovered two specific surface proteins that allow Burkholderia pseudomallei to attach to human cells for infection. Without these proteins, the group says the bacterium is much less infectious.
“This finding was significant because unlike most viruses, which have less than a dozen proteins, bacteria have thousands of different proteins. It’s like finding a needle in a haystack, finding which ones are important for infection and disease, and which ones can be used for an actual vaccine candidate,” Hoang said.
Hoang said they used the two proteins to create a vaccine and their study showed 100% effectiveness in mice. Unvaccinated mice died within five days, while 100% of vaccinated mice survived for at least one month, which was the duration of the study. Based on their finding, they submitted an application to the Defense Threat Reduction Agency, which was selected for funding.
“To develop this vaccine, we actually take the proteins by themselves and combine them with an adjuvant (a substance to increase efficacy or potency) to stimulate the immune response,” said Ian McMillan, who is microbiology PhD graduate at UH Manoa and co-researcher on the project. Our long term goal is to eventually take this vaccine and expand the testing into larger animal models. If successful, hopefully we’ll end up in clinical trials.”
To read the full findings of the team’s March 2021 study on Melioidosis, click here.