Pesky Mosquitos Spread Dengue Fever

Dengue fever is spread by the bite of a mosquito similarly to the way malaria is spread, but the bite of the dengue mosquito, Aedes aegypti, is much harder to evade. Aedes aegypti bites during the day, whereas malaria mosquito of the genus Anopheles bites at night. So, incorporating bed nets as a preventative action won't work to prevent dengue in the same way it does for malaria. Increasing numbers of dengue cases are being seen globally, and currently there is no cure or preventative vaccine for the disease. The dengue virus spread by Aedes aegypti causes a intensely painful disease, and in the most severe cases, the virus has a 12% mortality rate.


The Centers for Disease Control and Prevention (CDC) lists the primary symptoms as high fever, severe headache, severe pain in joints and behind eyes, muscle and bone pain, and rash.

The most severe form of the disease, dengue hemorrhagic fever, shares the same symptoms as listed above, but continues to worsen and cause capillaries to become "excessively permeable." If this isn't stopped, nutrients and fluid cannot be contained by the capillaries, and the body will go into shock. At this point, death isn't far away. 

Just last year, Australia native Manu Toigo contracted dengue hemorrhagic fever after being dropped off in the Panamanian Jungle as part of the Discovery Channel's TV show "Naked and Afraid." Toigo was diagnosed just days after returning to her current home in Los Angeles after finishing the show.There's no cure for any form of dengue, but Toigo was hospitalized and given fluid replacement therapy. She survived but still has to deal with the aftermath of her infection. Listen to the details told by Toigo herself in the following video:



So aside from exposure after a reality TV experience, what is the risk of being bitten by a mosquito harboring dengue for Americans? It's hard to say, because "up to 75%" of people infected with dengue end up just being carriers, meaning they don't actually show symptoms of having the virus. Then the virus is easily spread because these people don't go to the doctor, more mosquitoes bite them, pick up the virus, and go to bite and infect other people. Even parts of the world where dengue is not usually seen can be affected if a carrier visits this place and local dengue-compatible mosquitoes bite them. 

Since the dengue mosquitoes bite during the day, it's been difficult to prevent the transmission of the dangerous virus. Currently prevention efforts include mosquito control via pesticides and male sterilization.

As far as a vaccine for dengue, an answer could be on the horizon. Six preventative vaccines are already in clinical trial states. The most effective so far is being studied by pharmaceutical company Sanofi, "whose vaccine was shown to cut incidence of the virus by 61% in late-state trials" (CNN). 

There's still much work to be done in the battle against dengue fever, but signifcant progress has been made. Hopefully within the next year scientists will triumph over the rare but harsh disease. 

Source: CNN