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Introduction: Dengue fever has spread to be endemic in addition of 100 countries to a total estimate incidence of 50 – 100 million cases annually globally. About 0.7% of these cases become the complication that is dengue hemorrhagic fever which is severe and leads to about 22,000 deaths annually.
The pathogenesis of benign dengue fever becoming dengue hemorrhagic fever, and aspects of the immune-response behind it, have remained relatively unknown.
Methods: Existing literature on the Topic was retrieved through Google Scholar and PubMed searches, and the literature reviewed.
Results: Dengue hemorrhagic fever appears commoner in females and those with co-morbids such as diabetes-mellitus and obesity. Also, the case-fatality rate in severe dengue appears much bigger in females. The reasons for this are largely unknown but the additionally robust immune response in females, resulting in females to be additionally prone to develop bigger inflammatory response or enhanced susceptibility to capillary permeability could be the reason.
It has been shown that viremic-load, including the initial viremic-load at the bite of the Aedes-mosquito may be a factor leading to dengue hemorrhagic fever.
Yet different factors felt to be causative in the pathogenesis of dengue hemorrhagic fever include the role of the viral-protein, and then that which is termed the original antigenic-sin, the antibody-directed enhancement, autoimmunity, inhibition of interferon-alpha and cytokine-storm within the memory-cells.
Regionally, certain different strains of the DENV also seem to be associated with dengue hemorrhagic fever.
Newer-vaccines, based on the immunology of the disease, offer much hope in the near future.
Conclusion: Much knowledge has been forthcoming in realizing the pathogenesis of dengue hemorrhagic fever. But, additional studies need to be done.