Approximately one-half of all infants are infected with the respiratory syncytial virus (RSV) during the first year of life, and almost all children have been infected at least once by the time they reach their second birthday. Researchers at West Virginia University have discovered what makes RSV such a severe and persistent illness.
Senior author Giovanni Piedimonte, M.D., and his team have discovered that RSV prompts the release of a molecule that keeps the invaded cells alive despite the infection. The mechanism allows infected cells to survive for a longer period of time while they continue to produce viral particles, thus contributing to the severity and persistence of the infection.
Research results are published in the current issue of the journal PLoS ONE.
Inflammation of the airways caused by RSV often results in wheezing, cough and respiratory distress, creating the most common respiratory infection in infancy or childhood. Each year, an estimated 125,000 infants in the United States are hospitalized with RSV, the leading cause of infant hospitalization.
"There is still no effective therapy or medical treatment for RSV infection. While often mild, it still is responsible for the deaths of hundreds of infants in the United States each year," said Dr. Piedimonte, chair of the WVU Department of Pediatrics and physician-in-chief of WVU Children's Hospital. "The virus also strikes in nursing homes and causes deaths in the elderly population, so understanding how it works is critical."
Piedimonte said up to 500 infants may die of the infection each year. RSV may also predispose children to long-term health problems such as asthma. Other groups at high risk for severe RSV disease include the elderly, adults with underlying respiratory or cardiac disease, and those with a compromised immune system.
"Viruses must find a way to survive inside the host, and in this case RSV has found a way of keeping alive the cells that they infect," Piedimonte explained. "The virus invades the cell, which then produces a small molecule called NGF, or nerve growth factor. NGF allows the cell to survive while the virus reproduces itself. Finally, the cell explodes releasing new viral particles ready to infect the neighboring cells."