Millions of malaria diagnoses may actually be brucellosis

Brucellosis is a serious and often neglected disease endemic to many low- and middle-income countries around the world. Because it shares many of the same clinical symptoms as malaria—including fever and joint pain—it can be misdiagnosed.

Until recently, scientists did not know how often brucellosis was mistaken for malaria or other febrile illnesses, but new research from the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) has discovered that as many as 7 million people worldwide may receive a misdiagnosis each year—vastly increasing the number of people estimated to have the disease.

The research is published in the journal BMC Public Health.

If a patient is misdiagnosed with malaria, any treatment they receive will be ineffective because the two diseases have different causes—malaria is caused by parasites spread through mosquitoes, while brucellosis is caused by bacteria spread through animals.

This not only means that millions of individuals are suffering without proper treatment, but also that most affected countries’ doctors, veterinarians and policymakers lack awareness of the disease’s characteristics and prevalence.

The VMBS research team, led by associate professor Dr. Angela Arenas, is now focused on providing information about the disease to educate these health professionals and leaders as well as community members in several countries.

A life-altering disease

Brucellosis spreads to people from major livestock species, including cattle, pigs, sheep, and goats, as well as through consumption of unpasteurized dairy products.

If the disease is not treated early, it becomes a chronic condition that can lead to neurological issues, cardiovascular issues, and potentially death.

“We call it a neglected disease because it’s underdiagnosed and there’s not enough funding to address it,” Arenas said. “Veterinarians and physicians don’t know about the disease, so they don’t know what to look for or how to diagnose it.”

Brucellosis symptoms can mimic malaria, typhoid, or even food poisoning, leading many people to get misdiagnosed multiple times before finally receiving the correct treatment, if they ever do.

“One of the major issues is that malaria is such a prevalent disease in many of these countries; it has hundreds of millions of cases per year,” said Dr. Christopher Laine, an assistant research scientist and epidemiologist in Arenas’s lab. “It’s very easy for brucellosis to get lost in that mix. But if just a small fraction of those diagnosed with malaria actually have brucellosis, you increase the incidence by millions.”

Refining the numbers

Arenas’s team has visited several countries affected by brucellosis over the years, including Uganda, Tanzania, Kenya, Cameroon, South Africa and Armenia.

The researchers collaborated with Dr. Valen Johnson, a Distinguished Professor in Texas A&M’s Department of Statistics and former dean of the College of Science, to develop statistical models that predict brucellosis incidence based on proven rates in similar countries.

“For example, Kenya had information from before they prioritized the disease—when there was no brucellosis diagnosis—and then after they prioritized it,” Laine said. “Overall, these countries found that 4–11% of their malaria cases were actually brucellosis. We took brucellosis rates from places like that and applied them to places that were very similar.”

When developing their final estimates, the team determined that there was likely a .25–4% increase to the global incidence rate of brucellosis—which would escalate the number of affected individuals by 2.1 million to 7 million people worldwide.

“We wanted to be very conservative in our estimates while still showing physicians out there that they need to start paying attention to brucellosis,” Laine said. “Because, even if they’re only wrong once out of 400 times, that still equals millions of cases overall.”

A real-world impact

While the team is continuing its research—including studying bacteria prevalence in raw milk and testing individuals it suspects to be misdiagnosed—it will also continue its education and outreach missions.

“We’re focused not only on finding the problem but also telling the policymakers and stakeholders what to do next,” Arenas said. “We need to create awareness among them that the brucellosis problem is huge compared to what they were thinking.”

The team works with small-scale farmers, professors, physicians and public health personnel in affected countries to educate them about the disease’s symptoms and how it spreads. Veterinarians also play a major role in controlling the spread of the disease.

“If we control the disease in animals, we control the disease in humans,” Arenas said.

The team is also providing new training opportunities for the next generation of researchers in affected countries who are hoping to dedicate their careers to fighting brucellosis and similar diseases.

“Right now, our team has three Ph.D. students from Cameroon who got all their degrees in Africa but came here to get trained,” Arenas said. “We’re focused on sustainability and empowering these individuals so that once we leave their countries, they can fight the disease themselves.”

Brucellosis also holds importance for currently unaffected countries like the U.S. because of how quickly it spreads and its potential use as a bioweapon.

“If we are not prepared and we don’t have all the international stakeholders aware of and creating countermeasures to prevent, detect and control the disease, it could have a huge societal impact at the global level,” Arenas said. “It’s very important to control it there so it doesn’t come back here, either naturally or in a nefarious manner.”