We thank Dr Eisenhut for sharing with us the importance of clinical symptoms for differential diagnosis of dengue fever and dengue hemorrhagic fever with other viral hemorrhagic fever including Lassa fever and yellow fever. In this aspect, we concur that physical findings are essential in disease diagnosis and clinical management. It is however noteworthy that symptoms of Lassa fever may range from asymptomatic to hemorrhagic fever. Additionally, clinical symptoms in some patients, particularly during the early phase of disease are non-specific, ie, fever, headache, and myalgia and incubation periods may last up to 2 weeks. Similarly, symptoms of yellow fever may range from undifferentiated fever during the acute phase to hepatic impairment and other severe complications during the toxic phase. In recent imported cases of Lassa fever, a period of up to 16 days (median of 10 d) was taken to identify patients as potentially infected.– Thus, we have highlighted the need for laboratory diagnostic tools to assist in differential diagnosis of dengue fever, particularly in travelers from Lassa fever and yellow fever endemic regions.
As with Lassa fever, early intervention of dengue fever may be life-saving. In disease diagnosis, clinical diagnosis in health care settings provides frontline response and information for implementation of appropriate laboratory diagnostic tests. An overall clinical approach encompassing key components that consist of epidemiological background and patients' travel histories, including incidences of exposure to pathogen and prevention measures taken, as well as consideration of clinical features and laboratory test results would be essential for differential diagnosis, early disease detection, and confirmation.