There’s a little-known disease called melioidosis, and we need to talk about it. It has a fatality rate of up to 70 percent, likely kills the same number of people each year as measles, resists a whole host of antibiotics and, if that wasn’t bad enough, is caused by a potential bioweapon. So why isn’t it getting attention? That’s the take-home message from a new study, the first to estimate the global burden of this deadly disease.
Published in Nature Microbiology, the authors report that melioidosis is likely severely underreported in the countries it’s known to be present in, and could be endemic in 34 that have never reported a case. They estimate around 165,000 cases per year, but predict that this number is only going to rise alongside increasing rates of its major risk factors, like diabetes.
“The large numbers of estimated cases and fatalities emphasize that the disease warrants renewed attention from public health officials and policy makers,” the authors write in their study.
First coming under scientists’ radars more than 100 years ago, melioidosis is a bacterial disease caused by Burkholderia pseudomallei. Typically found dwelling in the soil of tropical countries, this pathogen can persist in the environment for up to six years and, worryingly, can also linger in drinking water supplies. Although the main route of exposure is through cuts on the skin, it’s thought to be transmissible through inhalation following extreme weather events, which kick up the bacterium from the soil and spread it around in the air. That’s why some countries consider it a potential bioterrorism agent and are investigating its potential to be weaponized.
There’s no vaccine, it’s resistant to a wide range of drugs, and it’s very difficult to diagnose. Nicknamed the “great mimicker,” its extensive list of symptoms can result in confusion with other diseases, like tuberculosis and pneumonia. That said, signs can also be nonspecific and thus tricky to attribute, thus good microbiology labs are often needed for diagnosis, a luxury developing areas are often not afforded.
X-ray shows left lung abscesses caused by B. pseudomallei. Jaturawutthichai/Shutterstock
For these reasons, melioidosis is probably underreported, and previous attempts to assess burden on the globe only went as far as mapping documented cases, which doesn’t exactly paint a complete picture. To improve on this, scientists headed by a group at Oxford University compiled a range of data to estimate both the incidence and fatalities due to this disease last year.
They started off by looking at both human and animal cases of melioidosis, and then mapping the environmental presence of B. pseudomallei using more than 100 years’ worth of published reports. Then, they used a statistical model to estimate the areas suitable for hosting this pathogen across the globe, taking into account things like optimal soil type and temperature.
From this, the authors were able to estimate that there were 165,000 cases of melioidosis last year, which resulted in almost 90,000 deaths – just shy of the number that measles kills (95,000). Furthermore, they predict it’s present in significantly more countries than it is reported in. Cases have been documented in 45 countries, but it’s likely endemic in 34 more that have not documented any cases to date. And with increasing rates of diabetes and travel, cases are probably going to increase in coming years. The authors therefore call for higher prioritization and greater awareness so that this deadly disease no longer remains dangerously neglected.