Dengue diseases are potentially life-threatening diseases caused by the Dengue virus. The virus (sero-types 1-4) is transmitted in nature by day-biting Aceder mosquitoes.The primary and secondary infections of the dengue virus exhibit different clinical profiles. Primary Dengue infection, also known as Dengue Fever, is the most common type of dengue illness. It is associated with mild to high fever, headache, muscle pain, and skin rash.
The secondary infection is known as Dengue Hemorrhagic Fever (DHF) or Dengue Shock Syndrome, and often results in high fever and, in many cases, hemorrhagic events and circulatory failure.Serological studies have shown that during primary infections, dengue-specific IgM antibodies are found by the 5th day of infection and remain in circulation for 30-60 days. IgG antibodies appear by the 14th day of infection and persist for life. In contrast, during secondary dengue infection, specific IgG and IgM antibodies significantly increase at 1-2 days and the 20th day after infection, respectively. Thus, different profiles of humoral immune responses in primary and secondary dengue viral infections can be used for differential diagnosis. This is of clinical significance in predicting progression and prognosis of the disease.