Oct 15 2007
New techniques have enabled scientists to carry one of the most comprehensive studies of adenoviruses ever performed in the United States.
Adenoviruses are viewed as the culprits in common respiratory illnesses such as colds, bronchitis and infections of the stomach, intestine, eyes and bladder, but they can also cause chronic airway obstruction, a heart infection called myocarditis, a potentially deadly bowel condition called intussusception and sudden infant death at birth; they also sometimes cause epidemics.
By adapting a rapid and accurate new molecular test strategy, scientists have been able to identify the adenovirus type in a matter of two days rather than the previous method which takes weeks.
The speedier method means that public health officials in particular will be better equipped to understand and deal with outbreaks of adenovirus in communities such as hospitals and long-term care facilities where people are in close contact.
It also will also help experts determine what type of adenovirus is causing the infection so that the appropriate antiviral treatment can be prescribed.
The new findings which come from extensive adenovirus epidemiological data collected in the United States, has also revealed that adenoviruses may cause more severe disease than others and some strains, particularly those considered as emerging pathogens, are more often associated with severe disease and death.
The new gene sequencing strategy which was developed by researchers at the U.S. Centers for Disease Control and Prevention, was used by researchers at the University of Iowa.
In an effort to better understand how adenovirus infection is caused and spread Dr. Gregory Gray and his colleagues analysed clinical adenovirus-positive samples and patient data from 22 military and civilian medical facilities over a 25-month period.
They characterized the strains of 2,237 adenovirus-positive specimens and compared their sequences with those of the 51 recognized strains that infect humans.
The team of researchers found, among other things, that adenovirus type 21 infections, may cause more disease and have become more common.
The researchers found that 50% of the clinical adenovirus isolates among civilians were associated with hospitalization, about 20% with a chronic disease condition, 11% with bone marrow or solid organ transplantation, and 4% with a cancer diagnosis.
The scientists say children under seven years of age, people with an underlying chronic disease, and those with recent organ transplantation are at greater risk of adenovirus infection and disease.
A considerable number of transplantation patients were found to have infections with multiple adenovirus isolates over time and the researchers say quickly recognizing the adenovirus type is the key to starting the appropriate antiviral therapy, controlling outbreaks and understanding the association of adenoviruses with a number of chronic disease conditions.
Funding for the study was provided by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health and it is published in the November edition of Clinical Infectious Diseases.