How Dengue Fever Could Hasten Malaria's Deadly March on Africa
Dengue fever is not to be taken lightly, but compared to malaria, it is a far less deadly mosquito-transmitted disease. Unfortunately, the illnesses tend to share very similar starting symptoms, causing frequent misdiagnoses in areas endemic for both diseases. Now new research shows that these mistakes not only impact individual patients, but could be helping malaria become an even greater danger.
"We believe dengue to be one of many diseases with classic fever and headache symptoms that are currently being misdiagnosed as malaria on a massive scale," Justin Stoler, a researcher with the University of Miami (UM), explained in a statement.
Stoler recently led his colleagues in an investigation of West Africa's mosquito-borne epidemics, finding that not only has the troublesome dengue fever found its way (unannounced) into Ghana, but it's causing rampant confusion in the midst of the undeveloped region's desperate battle against malaria.
The results of the investigation were recently published in The American Journal of Tropical Medicine and Hygiene.
According to the researchers, Ghana's under-resourced healthcare facilities are often unable to confirm suspected malaria cases with blood tests, with well over 60 percent of all diagnoses remaining in dispute. They also often can't wait for a test to become available, as the mosquito-borne parasitic disease is aggressive and very deadly, requiring prompt treatment.
According to the World Health Organization (WHO), this promptness has actually allowed malaria mortality rates to decrease by an encouraging 54 percent in African regions between 2000 and 2012. However, that didn't stop the disease from claiming an estimated 584,000 lives in 2013 alone. (Scroll to read on...)
By comparison, the viral dengue fever, which remains a leading cause of illness and death in the tropics and subtropics, only kills up to five percent of treated victims. Untreated or misdiagnosed victims, on the other hand, face a mortality rate as high as 50 percent.
Worse, the approach to malaria treatment is radically different than how doctors treat dengue, as malaria is caused by tiny microorganisms, not a virus. That's what Stoler and his colleagues are most worried about, suggesting that each misdiagnosis could help malaria grow stronger.
"The over-prescribing of anti-malarials puts evolutionary pressure on the malaria parasite that risks hastening its resistance to artemisinin-based combination therapy - the frontline drugs used to treat malaria in Africa," Stoler explained.
Such resistance is already spreading across Southeast Asia, and he worries about what kind of damage it could do in a vulnerable West Africa.
The researcher also found that a stunning 21 percent of blood samples from children infected with malaria had evidence of living with dengue.
"If these children who were confirmed to be malaria-positive also tested positive for dengue exposure, imagine what the incidence of dengue could be in unconfirmed malaria cases," Stoler noted. "If these patterns hold in Ghana, then the misdiagnosis burden in other large urban areas in Africa could approach one-third of all outpatient visits, given the large volume of presumed malaria cases in health care facilities."
Still, the researcher presses that this does not mean that professionals should be discouraged.
"As the price and accuracy of rapid diagnostic tests and other diagnostic instruments improve, I think we have a chance to really make a difference in clinical settings," all just by getting the diagnosis right.
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