Post by Watchman on May 10, 2006 16:00:37 GMT -5
BY DELTHIA RICKS
Newsday Staff Writer
Reaching into history hoping to better understand the future, two research teams have reconstructed the devastating 1918 flu virus, discovering it was of avian origin and effectively jumped from birds to humans.
The scientific finding is virtually the same scenario feared by global health officials who are keeping an eye on the growing number of bird flu cases in Southeast Asia.
There, 116 people have contracted the infection -- probably from direct contact with fowl -- and nearly half of those sickened since late 2003 have died. If the virus changes genetically to allow easy transmission from person to person, scientists predict bird flu could become a replay of the 1918 global pandemic that killed at least 50 million people. No continent was left unscathed.
Trekking into the permafrost region of Alaska to unearth the remains of an Inuit Indian woman who died of the so-called Spanish flu, researchers in 1997 gathered tissue to retrieve fragments of the killer virus.
The sample was compared with those preserved by the U.S. military from World War I soldiers who died of the infection. Such protein snippets provided enough biological information for scientists to genetically engineer the pathogen in the lab, resurrecting a killer that mysteriously rose in September 1918 and just as mystifyingly vanished -- though not forever -- a year later.
"The main goals of the work were to understand why the 1918 flu was so deadly," said Dr. Christopher Basler, assistant professor of microbiology at Mount Sinai School of Medicine in Manhattan. Basler and colleagues used the samples' blueprint to begin re-creating the pathogen that infected one in four in the United States and killed about 550,000 nationwide.
Known as H1N1, the virus that caused the 1918 flu still exists in the form of third and fourth cousin subtypes that are not nearly as infectious. Basler said the high degree of virulence 87 years ago stemmed from a lack of human immunity to this early form.
Working with Drs. Adolfo Garcia-Sastre and Peter Palese of Mount Sinai, Basler created "plasmids," a necklace-like arrangement of genes. The scientists then shipped the plasmids to the Centers for Disease Control and Prevention where the plasmids were insinuated into human lung cells. Within days they emerged as fullblown replicas of the 1918 virus.
"We performed this work under high-containment conditions," said Dr. Terrence Tumpey, who led the final steps of reconstruction.
The viral re-creation was announced Friday and is detailed in the journal Science. Completion of the genetic sequencing is reported in today's journal Nature.
Dr. Jeffrey Taubenberger, chief of molecular pathology at the Armed Forces Institute of Pathology in suburban Washington, began the quest for the 1918 killer. He traveled to Brevig Mission on the Seward Peninsula in Alaska nearly a decade ago to gather evidence, preserved in the permafrost.
"One of the important things we've found so far is that the 1918 flu was an entirely birdlike flu that adapted to humans. It is different from the 1957 and 1968 pandemics, which were a mix of human and bird viruses."
Neither the 1957 Asian flu nor the 1968 Hong Kong flu was nearly as deadly as the 1918 strain, which was particularly lethal in young, healthy adults.
Taubenberger said both teams' studies reveal that today's bird flu and the infection of 87 years ago share many of the same genetic features.
Resurrecting a viral killer from the past is not new to science. In July 2002 a team of scientists at Stony Brook University announced they had created a polio virus from scratch.
Copyright 2006, Sun-Sentinel Co. & South Florida Interactive Inc.