Omicron is a rare virus. It was introduced into the U.S. in 1871. The virus is part of a closely linked family, which may be studied by some scientists as a kind of virus reservoir to which the human immune system may not be sufficiently adapted. Because of its unusual virulence and rarity, potential bioterrorism scenarios are also possible. [Where Should Scientists Spot Terrorism? A Scientist Explains]
The largest outbreak of omicron occurred in Siberia in 1916-1917, which resulted in 50 cases in the United States. Prior to that, a particularly virulent type of omicron was not seen in the U.S.
The small virus — some only a few hundred millionths of a millimeter in size — remained concentrated in two populations, one in a remote cave and the other in an isolated area in the Northern Caspian Sea. The Svalbard islands off the coast of Norway are where the virus grew into a distinct epidemic, according to a 2014 report by the U.S. National Science Foundation’s Laboratory for Infectious Diseases and Biosecurity (LIDB). This outbreak has been recognized as the cause of the flu-like symptoms now being experienced in Europe.
The virus evolved over time in these communities, according to the report. It now hides in urine, feces and sweat, in swimmers and cold water divers, researchers found.
An additional mutation, due to changes in its temperature range, was also noted, bringing the particle size from about 200 micrometers (about 2/10 of an inch) to about 16 micrometers (about 0.048 inch).
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One millionths of a millimeter is a millionth of a unit that measures distance. This is tiny. Scientists debate whether or not to call omicron a “simplex” virus — a measure of how rapidly its disease-causing protein can be multiplied by the cells in the small piece of membrane the virus holds together.
A change in circulating omicron seems to have been detected on March 2, the scientists said. The change occurred in a piece of tissue, not the virus itself. But the increase in sizes was small — one-millionth of a micrometer.
Even in humans, humans are not sensitive to the same kind of strain of the virus that would likely give rise to an avian flu strain, such as the H5N1 strain.
A few years after the concentration of this viral community was discovered in Svalbard, scientists began seeing clusters of illnesses and more often reports of human mortality.
Over the course of the last 100 years, more than 2,000 illnesses attributed to omicron were reported to the Centers for Disease Control and Prevention.
The rarity of the virus, and its potential for introduction into the U.S., are “a concern,” the report said.
Originally published on Live Science.
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