Mosquitoes are more than just annoying; in much of the world, they carry dangerous, sometimes fatal diseases. Many of these viruses are transmitted by a type of virus called alphavirus. There is another side of alphaviruses, however: researchers are looking at ways to use them as delivery mechanisms for vaccines and other medical treatments.
One that is particularly the subject of research is the newly discovered Eilat virus. Named for Eilat, an Israeli resort town in the Negev desert on the northern shore of the Red Sea, the virus was found recently in a mosquito sample collected there in the 1980s. It appears to be alone among the alphaviruses in that it can only infect insects, and has not shown evidence of being harmful to mammals, including humans.
This virus is unique—it’s related to all of these mosquito-borne viruses that cause disease and cycle between mosquitoes and animals, and yet it is incapable of infecting vertebrate cells, said Farooq Nasar, a graduate student at University of Texas Medical Branch at Galveston who has studied the virus, in a statement. “It’s a gift, really, because we can compare it to other alphaviruses and figure out the basis of their ability to infect a variety of animals, including humans.”
That means the structure and life cycle of Eilat virus can provide an unprecedented look at the mechanism by which other alphaviruses, which can infect humans, do their damage. Since diseases such as encephalitis are caused by alphaviruses, scientists may be able to use Eilat virus to develop new ways to treat and even prevent them. By adding bits of genetic material from other alphaviruses to Eilat virus, for example, researchers may have a safe way to look at how those viruses work—and how best to fight them.
Eilat virus might also see use in vaccination. A vaccine for a disease uses an inert form of that disease to stimulate an immune response, so that if the disease actually attacks, the immune system is already primed for it. Eilat virus, which is harmless in humans, nonetheless might be able to train the immune system to fight off alphaviral infections in humans and livestock.