According to the CDC, 50 to 100 milllion people, primarily in the tropics, are infected with dengue virus each year. There are approximately 500,000 cases of dengue hemorragic fever, and 22,000 deaths. There are no vaccines against dengue and no treatment for infection. The NS1 protein is detectable in human serum of infected individuals. It is a 50 kDa non-structural glycoprotein that interacts with intracellular membranes and the cell surface. The NS1 protein appears to utilize normal lipid metabolic pathways to affect the complement system and promote infection.
Gutsche, I. et al. (2011) Secreted dengue virus nonstructural protein NS1 is an atypical barrel-shaped high-density lipoprotein. PNAS. 108(19):8003-08.