Same symptoms as the flu, but your child may have a different virus

(HealthDay News) – With a late-season flu outbreak affecting hundreds of thousands of Americans, those familiar symptoms your child shows -- difficulty in breathing, coughing and fever -- may actually not be the flu at all.

Instead, a relatively new virus first discovered in New Zealand may be the culprit. That doesn't make things better, but it may alter the course of treatment.

Samples collected from ailing children as far back as 25 years ago show that the viral infection known as human metapneumovirus (hMPV) was responsible for about 12 percent of those infections, Vanderbilt University Medical Center researchers found.

Their original research, borne out in subsequent years, was published in the New England Journal of Medicine .

That ranks it just behind respiratory syncytial virus (RSV), which has been known for decades to cause such illnesses, says Dr. James E. Crowe Jr., professor of pediatrics and
assistant professor of microbiology and immunology at Vanderbilt and a member of the original research team.

"It's actually more important than influenza," Crowe adds.

Metapneumovirus was identified by researchers in the Netherlands in 2001. Studies since then have shown that a large percentage of children pick it up early in life.

The first encounter with metapneumovirus is likely to be the most serious, Crowe says, since the immune system is not acquainted with it; the average age of children in the study was 11.6 months.

But the virus can return, causing a less serious bout of illness, such as a common cold. And it can cause more severe infections in older people whose immune defenses have waned.

Right now, there is not much that doctors can do about metapneumovirus, since there is no drug to treat it and until recently, no easily done test to detect it.

But in January, the U.S. Food and Drug Administration approved a new diagnostic test that detects 12 respiratory viruses, including strains of flu that have triggered epidemics. The test also is the first to detect metapneumovirus (hMPV), which the agency said was first identified in 2001.

The xTAG Respiratory Viral Panel, made by the Toronto, Canada firm Luminex Molecular Diagnostics, is the first test to detect and differentiate between influenza A subtypes H1 and H3, among the most severe types of epidemic flu in people. The test analyzes and replicates viral genetic material found in secretions taken from the back of the throat. It's the first diagnostic that allows several of these tests to be processed using the same sample, the FDA said.

The test also detects forms of influenza B, which is less severe than influenza A; parainfluenza 1, 2, and 3, which are leading factors in croop and the common cold; rhinovirus, another frequent cause of colds; and adenovirus, a common cause of respiratory tract infections.

"One of the first things on everyone's list is a test that would be easier and cheaper to do than PCR," said Dr. Kenneth McIntosh, a professor of pediatrics at Harvard Medical School and co-author of an accompanying New England Journal of Medicine perspective article.

"It would be good to have because it would give a prognosis, and would tell physicians when they don't have to use antibiotics," he says. Antibiotics kill bacteria but don't affect viruses.

Metapneumovirus "is highly likely to be spread by secretions," passed literally from hand to hand, "so good hand washing would prevent most of the transmission," he says.

The new study is important because it shows metapneumovirus has been a cause of infection for at least 25 years, McIntosh adds.

On the Web

Advice about flu, colds and other respiratory infections can be found at the U.S. Food and Drug Administration.

SOURCES: James E. Crowe, Jr., M.D., professor of pediatrics and assistant professor of microbiology and immunology, Vanderbilt University Medical Center, Nashville, Tenn.; Kenneth McIntosh, M.D., professor, pediatrics, Harvard Medical School, Boston; Jan. 29, 2004, New England Journal of Medicine
Author: Ed Edelson, HealthDay Reporter
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