Commentary: Questions on West Nile Virus
Aug. 29 -- Outbreaks of encephalitis from the "West Nile" virus are not getting the proper scientific attention. The scope of the research is too narrow.
The potential importance of polluted and unhealthy environments in which West Nile virus outbreaks often occur is being ignored due to lack of funding and scientific indifference.
It's noteworthy that West Nile virus is typically described by scientists as a rare, mild and usually harmless infection in humans, affecting mostly the elderly. In birds, however, the virus has been highly touted as a killer.
Like Canaries in a Mine
Traditionally, birds have been viewed as sentinels for toxic environments, the canary in the mine being the most famous example.
What if some degree of the damage to birds and humans now attributed solely to the virus is actually triggered by harsh environmental factors that need to be addressed?
To date, attempts to prevent West Nile outbreaks have often relied on the spraying of mosquitoes. This is controversial and raises the possibility of further polluting a toxic environment that is already causing harm and contributing to the outbreaks.
Robert McLean is one of several federal scientists prominently involved in West Nile virus studies who understands the importance of also investigating environmental factors in the emergence of new diseases. For instance, some studies seem to show that toxic air pollution could potentially enhance the activity of a virus and make it churn out more copies of itself.
"Because we don't have the resources, we're missing the opportunity to look at many different factors that may be going on with West Nile," he said. As director of the Wisconsin-based National Wildlife Health Center of the U.S. Geological Survey, McLean now spends most of his time diagnosing and studying dead crows and other wildlife that turn up positive for a West Nile virus infection.
Dr. Ian Lipkin of Columbia University, who has played an important role in identifying the genetics of the West Nile virus, is an infectious disease scientist who thinks beyond microbes. He too believes that an understanding of disease comes from probing the relationship between environmental factors, including viruses and toxic substances, and the genetic endowment of individuals.
To Lipkin, it makes perfect sense to want to know more about how, say, "an unhealthy environment might break down immunity in both birds and humans and make them more susceptible to viral infection. It's worthy to pursue this."
Searching and Tracking
Even so, when all is said and done, both McLean and Lipkin are still focused on the biology and behavior of the virus. That's where the research action has been since the outbreaks began in New York City in the summer of 1999.
Much of the public health effort is aimed at tracking and identifying mosquitoes that transmit the virus, tracking and diagnosing dead birds, particularly crows, for signs of the virus and monitoring human blood samples for signs of infection.
Symptoms of human infection are said to include fever, headache, and body aches. The rare serious cases can involve inflammation of the brain, causing stupor, tremors, convulsions, paralysis and death.
In 1999, seven people who died and 62 people who became ill turned up positive for the virus. Last year, there were 21 cases, including two deaths.
So far this year, at least ten people, including four in Florida, one in Georgia and five in the New York City area have turned up positive.
Last month, a study published in The Lancet estimated on the basis of sample blood tests and interviews that 8,200 people in the New York City area in 1999 came down with asymptomatic West Nile infections and about 1,700 experienced some flu-like symptoms.