Newfound bug is old nemesis

CHICAGO – Something called the metapneumovirus, discovered just two years ago, is turning out to be an exceedingly common cause of human misery, responsible for garden-variety colds in grown-ups and more severe coughing, wheezing and congestion in children.

Researchers are beginning to piece together the scope of this ubiquitous but overlooked bug, which now appears to afflict just about everybody, probably over and over.

Even though the virus seems to be rarely serious, its vast presence intrigues microbiologists, and it is one of the most talked-about topics at this week’s meeting in Chicago of the American Society for Microbiology.

Experts say the metapneumovirus is almost certainly not a new bug but something that has been around for eons. Rhinoviruses are long considered the classic cold bug.

Like many other respiratory bugs, this one is most likely to cause severe illness in infants encountering it for the first time. Although repeat infections are thought to be common, they result in much less intense illness, often just an ordinary cold or perhaps no symptoms at all. However, the bug may cause more serious problems in the elderly and people with other medical conditions.

Research suggests that the metapneumovirus is second only to respiratory syncytial virus as a cause of severe lower respiratory infections in the young, occurring about two-thirds as often. Both viruses are members of the paramyxovirus family.

A team led by Dr. James Crowe Jr. of Vanderbilt University looked at nasal specimens taken from 2,000 children after they were treated for lower respiratory infections since 1976.

The newly discovered virus turned out to cause about 12 percent of these severe illnesses. They also caused 15 percent of common colds in children, including one-third of the colds complicated by middle-ear infections.

“When we put this in perspective, it appears to be the second most common cause of respiratory illnesses in children,” he said.

In other health news:

New research suggests men who have had prostate cancer treatment may be at dramatically increased risk of eventually dying from the disease if levels of a cancer-linked protein, PSA, double during the first three months after treatment. The findings suggest those men need immediate hormone-suppression therapy to try to delay the deadly spread of their returned prostate cancer, and should consider experimental treatments, the researchers reported Tuesday in the Journal of the National Cancer Institute.

Antibiotics failed to ward off heart trouble in the biggest study yet to test the theory that low-level infections play a major role in triggering heart attacks, researchers reported. The study was published in today’s Journal of the American Medical Association.

The U.S. infant mortality rate dropped to another record low in 2001, in part because of a decline in SIDS deaths, but is still higher than that of other industrialized countries, the Centers for Disease Control and Prevention government said Tuesday. The U.S. rate in 2001 – the latest data available – fell to 6.8 deaths per 1,000 live births from 6.9 the previous year.