Old virus causing new disease in United States

WASHINGTON (Reuters) - A strain of virus best known for causing colds and "stomach flu" is becoming more common and more dangerous, U.S. researchers report.

They said that adenovirus 21 was surprisingly common and was causing an unexpected level of severe disease and deaths.

The researchers used a new test developed by the U.S. Centers for Disease Control and Prevention and said the wider use of such tests might help doctors and health officials better understand what diseases are making people sick.

"It makes the case that if you did survey regularly and routinely for adenoviruses you would get more information and a little advance information on where the bad ones are likely to pop up and to be ready," said Dr. Catherine Laughlin of the National Institute of Allergy and Infectious Diseases, which paid for the study.

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Adenoviruses cause colds, bronchitis and stomach upsets, but can also cause chronic airway obstruction, a heart infection called myocarditis, a sometimes deadly bowel condition called intussusception and sudden infant death at birth.

Gregory Gray of the Center for Emerging Infectious Diseases at the University of Iowa and colleagues were trying to get a handle on which types of adenoviruses were most common and which were causing serious outbreaks of disease.

This had not been easy to do because the old diagnostic tests were slow and could not differentiate easily among the different strains of adenovirus. And doctors rarely test patients to see what infection they have.

"The new test is very elegant and specific," Laughlin said in a telephone interview.

Gray's team used the test on 2,200 samples from 22 U.S. medical facilities, including eight military sites. Military personnel are especially susceptible to outbreaks of all kinds of disease, including adenoviruses.

KILLER VIRUS

Adenovirus 21 was found in 1 percent of specimens in 2004, but in 2.4 percent in 2006. And it was making people much sicker than the other strains, killing 50 percent of bone marrow transplant patients, for instance.

These patients are at extra risk from infections as their entire immune systems are destroyed before they get transplants of new bone marrow tissue.

"For both populations, we observed a statistically significant increasing trend of adenovirus type 21 detection over time," Gray and colleagues wrote in their report.

And half of them were sick enough to be hospitalized.

"The high prevalence of hospitalization among the patients with adenovirus infection was surprising," Gray's team wrote in their report, published in the journal Clinical Infectious Diseases.

Laughlin said the test would need to be commercialized, but having it available might encourage companies to develop better drugs and vaccines against adenoviruses.

"I think there will also be more effort in drug and vaccine development, especially because the numbers of immunosuppressed people that we have around really has been increasing," she said -- including cancer patients, organ recipients and people infected with the AIDS virus.

The Department of Defense has also contracted for a new vaccine against adenovirus types 4 and 7.