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Smith Biologist Leads Effort to Wipe Out Parasite

With Smith biologist Steven A. Williams on sabbatical, his office in the Science Center has been turned into storage space for cardboard boxes packed with blood, mosquito and urine tests, awaiting shipment to distant locales.

The cartons are earmarked for tropical regions in Africa, Asia, Latin America and the South Pacific, where mosquitoes quietly and consistently spread a certain parasitic worm from human to human – infecting more than 150 million people and placing at risk more than a billion.

Williams, the Gates Professor of Biological Sciences, along with a group of researchers from a smattering of the nation’s leading research institutions, recently published a significant discovery in the effort to eliminate that parasitic worm: the complete sequence of its genetic code.

Now the work can begin to develop a vaccine and new drugs to wipe out the filarial parasite and, by extension, the debilitating diseases it causes.

But just getting to this point was a significant undertaking. Solving the worms’ genetic code eventually involved 71 researchers – 12 of whom have connections to Smith – whose names appear at the top of their paper in the Sept. 21 issue of the prestigious journal Science.

That was a far cry from the project’s modest beginning in Williams’ lab, where he coordinated the genome effort for the World Health Organization from its inception in 1994 to its completion in 2005, and where the actual work to decipher the genetic code began.

The researchers in Williams’ lab had read 100 million nucleotides of the worm’s genetic code by the time the project received a funding infusion from the National Institutes of Health in 2003 and the work shifted to a larger research facility that sped up the process of reading the remaining 750 million.

“Parasites are difficult to study because they live inside another organism,” said Williams. “The only realistic approach was to study the DNA and get at it at the molecular level.”

Any new drugs or vaccines that result from the knowledge of the worms’ genetic code would be welcome news to the victims of the disease elephantiasis, whose current drug options only target the larvae and do not completely kill adult worms, which can live up to eight years in the human body.

Its elimination would also be welcome news to the World Health Organization, which established that as a goal at the beginning of this decade – an ambitious idea considering that scientists have only been able to rid mankind of one disease throughout history: Smallpox.

And, developing new vaccines and drugs may not be all that is necessary to reach that goal.

Recognizing that, Williams is now  helping coordinate a $14 million project involving five other principal investigators and funded by the Bill and Melinda Gates Foundation, which aims to pinpoint the potential weaknesses in that plan and identify ways to circumvent them. He is currently doing the work in an office at the Lymphatic Filariasis Support Center, Task Force for Child Survival and Development, in Atlanta.

One potential weakness Williams and the other researchers working with him have identified is the ability to track the worm and the diseases it causes as it spreads from person to person by mosquitoes.

“To eliminate lymphatic filarial disease we need the ability to track the disease and that means identifying people with low levels of infection,” he said.

Victims of infection often do not realize they are sick until they begin to be disfigured, their limbs expanding to painful proportions by elephantiasis. So, to identify people who have the parasite before symptoms occur, Williams developed a simple blood test.

And, as the cartons of blood tests in Williams’ office are shipped to places around the world, he will continue working toward the goal that the WHO established.

As Williams recently noted, now that the genetic code has been solved, "we can find the Achilles heel of the parasite and eliminate it."