Dengue

A debilitating viral disease of the tropics, transmitted by mosquitoes, and causing sudden fever and acute pains in the joints.

Causes

Dengue fever is caused by any one of four dengue viruses spread by mosquitoes that thrive in and near human lodgings. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. When the infected mosquito then bites another person, the virus enters that person's bloodstream.

Sign and symptoms

Dengue Fever Symptoms and Signs. Primary symptoms of dengue appear three to 15 days after the mosquito bite and include high fever and severe headache, with severe pain behind the eyes that is apparent when trying to move the eyes. Other associated symptoms are joint pain, muscle and bone pain, rash, and mild bleeding.

Vaccination

There are a number of dengue vaccine candidates in different stages of development. The more advanced consist of tetravalent mixtures of live attenuated viruses representing each serotype. Different attenuation mechanisms have been used to develop three of the leading candidates:

Chimerization with yellow fever 17D vaccine strain, developed by Sanofi Pasteur

Combinations of defined mutations/deletions and chimeras, developed by NIH

Chimerization with dengue 2 PDK53 virus, attenuated by cell culture passage, developed by Inviragen/Takeda.

One disadvantage of all live attenuated vaccine candidates in clinical trials is that a single inoculation is not sufficient to induce protection to all 4 serotypes, probably due to viral interference among the live components of the vaccine.