Emergence of travel: Associated dengue fever in a non-endemic, hilly state

Background: We assessed the occurrence of dengue fever in association with travel in a non-endemic hilly region. The clinical presentation and laboratory parameters of febrile patients with a travel history to an endemic region were studied, and the role of the laboratory in the diagnosis was affirmed.
Materials and Methods: Febrile patients presenting with clinical features defining dengue with a history of travel to an endemic area constituted the study group.Serum samples were tested for dengue-specific NS1 antigen and IgM, IgG antibodies. The demographic data were retrieved from the hospital information system. A hematological and biochemical workup was done and the results analyzed using percentage, proportion, mean, and median.
Results: Out of 189 febrile patients, 58 were reactive to serological tests for dengue, with 47 (81%) males. The presenting features were chills and rigors, myalgia, cough, sweating, and vomiting. Thrombocytopenia (74.35%), lymphopenia (52.94%), and leucopenia (47.05%) were present in early disease, with AST >34 IU/L in 58.97% of the patients. The NS1 antigen was detectable between three and seven days of fever and the IgM antibodies after five days. The positivities to only NS1, both NS1 and IgM, and IgM alone were 60.34, 27.58, and 10.34%, respectively, and the median duration of fever was five, seven, and ten days, respectively. One case of dengue hemorrhagic fever and one of probable secondary dengue infection with detectable IgG were encountered.
Conclusion: Dengue fever remains unsuspected in febrile cases in non-endemic regions. History of travel is an essential criterion to suspect dengue. A non-specific clinical presentation eludes diagnosis. Serological tests for antigen and antibodies, and hematological and biochemical markers are vital for distinguishing the diagnosis.