Panel 54. The dengue virus represents another member of the Flavivirus family, also transmitted by mosquito bites. These images show sections of cells infected by this virus. The photograph at the top shows multiple membrane rearrangements that are the site of the replication of the viral genome. They are slightly different morphologically from those induced by the West Nile virus, but their role is identical. The photograph at the bottom shows an area of this cell that contains membrane rearrangements and viral particles, at high magnification. The morphology of this virus is comparable to that of the West Nile virus. However, infection by this virus has much more significant consequences than in the case of the West Nile virus. The pathology is not only more severe, but the dengue virus is efficiently transmitted from human to human, with the human species constituting the reservoir of the virus. Moreover, there are 4 subtypes of this virus, and while infection by one subtype can induce protective immunity against the same subtype, it does not prevent reinfection by another subtype.