Transmittance of the Virus

The DEN family of viruses are blood-bound viruses transmitted from humans to mosquitoes to other humans. The virus is spread when a mosquito bites a human in the first three days of that human's Dengue infection. The virus is then incubated in the stomach of the mosquito, infecting certain types of cells. The salivary glands of the mosquito become infected in 8 - 11 days after ingestion. At this point, the mosquito can transmit the virus to another human by ingesting the human's blood. When the mosquito does this, minute droplets of its infected saliva are transferred to the human blood stream, infecting the human.

Effects of the Virus

There are four different known forms of the virus. When infected with one form of the virus, patients typically experience fever, rash, muscle and joint pains. These individuals are rarely at risk of acquiring DHF (Dengue Hemorrhagic Fever) though. Once their body fights off the invading infection, the body acquires an immunity to that form of the virus. However, this immunity does nothing to protect the victim against other forms of the virus. In fact, the antibodies make the situation worse when the body comes in contact with a different mutation of the DEN virus. When the body produces antibodies for one form of the Dengue virus, it produces a small amount of antibodies that will recognize the other form of the virus. The problem is that not enough antibodies are created to signal the immune system to fight off the invasion. Instead, other immune cells, monocytes, take up the virus. This allows the virus to infect the monocytes, something that does not happen when the body is infected with its first Dengue infection. In essence, the disease is different the second time around. This time, the infection is much more serious, usually resulting in Dengue Hemmorhagic Fever. This form of the illness causes a weakening of the blood vessel walls, which erupt and cause internal bleeding. The disease requires hospitalization for half a million people every year. 25 thousand of them die.



December 1, 1996