|Description:||This 2006 photograph depicted a female Aedes aegypti mosquito while she was in the process of acquiring a blood meal. The feeding apparatus consisted of a sharp, orange-colored “fascicle” that was covered in a soft, pliant sheath called the "labellum” while not feeding. The labellum was shown here retracted as the sharp "stylets" contained within pierced the host's skin surface, thereby, allowing the insect to obtain its blood meal. The orange color of the fascicle was due to the red color of the blood as it migrated up the thin, sharp translucent tube. When viewed in cross-section, the larger of the two needle-sharp stylets, known as the "labrum", takes on the shape of an inverted "V", and acts as a gutter, which directs the ingested host blood towards the insect's mouth. This female’s abdomen had become distended due to the blood meal she was ingesting, imparting the red coloration to her translucent abdominal exoskeleton.|
The first reported epidemics of Dengue (DF) and Dengue hemorrhagic fever (DHF) occurred in 1779-1780 in Asia, Africa, and North America. The near simultaneous occurrence of outbreaks on three continents indicates that these viruses and their mosquito vector have had a worldwide distribution in the tropics for more than 200 years. During most of this time, DF was considered a mild, nonfatal disease of visitors to the tropics. Generally, there were long intervals (10-40 years) between major epidemics, mainly because the introduction of a new serotype in a susceptible population occurred only if viruses and their mosquito vector, primarily the Aedes aegypti mosquito, could survive the slow transport between population centers by sailing vessels.