Detecting Chronic Malaria

Research published today in the Journal of Clinical Investigation Insight suggests that in people with chronic malaria, certain metabolic systems in the blood change to support a long-term host–parasite relationship. This finding is key to eventually developing better detection, treatment, and eradication of the disease.

According to first author Regina Joice Cordy of Wake Forest University, chronic infections—which often go undetected—account for about 75% of all malaria cases. Even if the chronic malaria has no symptoms, the host still provides a fertile environment for the malaria cells to grow, transfer through mosquitoes, and spread. In its acute form, the disease can lead to coma in children and multiple organ failure in adults.

While research has shown that people with acute malaria have more of the parasite in their bloodstream and have a different immune response in repeat infections, there has been no clear understanding of how the parasite and host respond during chronic asymptomatic malaria infection. This study is a step in that direction.

“The human body is very complex,” Cordy says. “In addition to immune responses, our bodies have all kinds of metabolic pathways that can be activated at any given time. We wondered if there were metabolic factors that we weren’t considering when thinking about malaria infection.”

The researchers focused on identifying changes in blood metabolites in both humans and rhesus macaques infected with the disease. They found different blood chemistry in acute versus chronic infections, with striking differences in amino acids and lipids.

“We saw metabolites changing during the acute phase—a lot of them—and it may be that both parasite and host alter their metabolic activity,” Cordy explains. “In chronicity, it’s not that the host eliminates the parasite. The parasite stays there, but it stays there differently.”

Cordy also claims that this study helps illustrate how a successful parasite can coexist in its host without killing it. “In this study, we observe a series of changes in metabolic activity as host and parasite go into a state where they’re coexisting,” she says. “It seems they adapt to each other in a metabolic sense.”