Severe cases of a common travelers' infection may not be recognized if doctors rely on the World Health Organization's (WHO) guidelines for identifying it, according to a new study published in the April 15 issue of The Journal of Infectious Diseases, now available online.
Dengue is the most important emerging disease among international travelers, with a 30-fold increase in incidence over the past 50 years worldwide. Like malaria, dengue is transmitted to humans by mosquitoes.
Most cases are mild. Symptoms include fever, rash, headache, pain behind the eyes, and muscle and joint pain. According to the WHO, dengue hemorrhagic fever (DHF) is characterized by fever, low platelet count, clinical evidence of leaking capillaries, and spontaneous bleeding or fragile blood vessels. The most serious cases can lead to shock and death. There is no cure for dengue infection, but management of the disease's effects can prevent the worst outcomes.
The study, conducted by Ole Wichmann, MD, MCTM, DTM&H, at the Robert Koch Institute in Berlin, Germany, and colleagues throughout Europe, collected data through the European Network on Surveillance of Imported Diseases at 14 sites in 8 European countries.
Out of more than 200 patients treated for dengue infection at these sites over two years, less than 1 percent fit all four criteria necessary to meet the WHO definition of DHF. However, 11 percent had at least one manifestation of severe dengue disease, and a total of 23 percent required hospitalization due to dengue-related symptoms.
"Dengue exists more as a continuous spectrum," Dr. Wichmann said. "Severe disease can be present in patients who do not fulfill all four DHF criteria."
"The term 'dengue hemorrhagic fever' puts undue emphasis on bleeding," he added, noting that plasma leakage and shock can occur without it. "Clinicians who mainly focus on bleeding...may miss the most important conditions that require hospitalization and treatment."