Taking the sting out of summer
Dr. Tom Hobman is looking for a new approach in the fight against West Nile and other viruses.
Story by Connie Bryson/Illustration by Amanda Woodward
For most of us, it's a seasonal thing. As summer approaches, our thoughts turn to the outdoors—barbecues on the deck, camping, a day at the lake. And mosquitoes. And West Nile virus. But unlike most of us, AHFMR Scientist Dr. Tom Hobman doesn't wait for summer to think about West Nile virus; he thinks about it year-round. He has been studying it since 2005.
"Although most strains of West Nile are relatively harmless, the strain that has gained a foothold in North America is more likely to make people sick," says Dr. Hobman, a researcher at the University of Alberta. "Because there is no specific treatment or vaccine, West Nile virus infection is a significant medical concern."
According to the US Centers for Disease Control and Prevention, roughly 80% of people who are infected with West Nile virus do not show clinical symptoms. However, a small but significant number develop severe illness, including neurological effects—such as vision loss, tremors, numbness, and paralysis—that may be permanent. According to the Public Health Agency of Canada, the most serious effects can even be fatal. These conditions include meningitis (inflammation of the membranes surrounding the brain), encephalitis (inflammation of the brain itself), and acute flaccid paralysis (a polio-like syndrome that can result in the loss of function of one or more limbs).
"Current research is focused on understanding how the virus causes disease," says Dr. Hobman. "This is where my lab comes in. I'm interested in the consequences of the interactions between proteins made by the virus and proteins that are in the cells infected by the virus.
"It's important to understand that the goal of a given virus is not to cause disease. Rather, the virus needs to find a susceptible host cell, get into it, replicate its own genome (hereditary information), get out, and find another host cell in which to repeat the process. Viral disease is a result of harmful interactions that occur when the virus is replicating."
Dr. Hobman's team studies a class of proteins made by certain viruses including West Nile. The proteins are called capsids, and their main job is to bind the viral genome and place it in a protective shell. Capsids have long been thought of as inert building blocks. But this view is changing, because the research of Dr. Hobman and others has linked capsids to causing death in neurons (nerve cells) and other types of cell, implicating them in the neurological effects caused by West Nile virus.
"Now we are trying to find out which proteins in the host cells interact with the viral capsids," says Dr. Hobman. "Then we can look for ways to disrupt these interactions." This represents a new approach to dealing with viral infections. Currently most antiviral drugs target viral proteins. The problem is that many viruses, West Nile and influenza included, mutate very rapidly and, consequently, can quickly develop resistance to drugs. If we target the host-cell proteins, viruses should be much less likely to develop drug resistance."
Notes Dr. Hobman: "This field is in its infancy, and I think it will flourish. It's not clear at this point how the research will develop into practical treatment; but it's safe to say, the applications go beyond West Nile virus. For example, the capsid proteins of West Nile virus are similar to the capsids of the viruses that cause dengue and hepatitis C. This is a promising avenue of research."