Cold, Flu, & Cough Health Center

Killer Cold Virus Appears in U.S.

U.S. Ad14 Outbreaks continued...

Texas, February 2007: Beginning last February, recruits undergoing basic military training at Lackland Air Force Base started coming down with adenovirus infections. From February through June, 90% of analyzed virus isolates were Ad14.

During this time, 27 of these previously healthy young adults were hospitalized for pneumonia. Five went to the ICU. One died. Throat swabs were taken from 16 of these patients, including all five ICU patients. All tested positive for Ad14.

Investigators tested 218 health care workers from the hospital units that treated the recruits; six were positive for Ad14. Five of the six had treated hospitalized Ad14 patients.

The base continued to have a high rate of respiratory illness, with 55 cases from Sept. 23-29, the last week for which test results are available.

An additional 220 cases of Ad14 infection turned up during tests at other Texas military bases that received Lackland recruits. Ad14 was also found in an eye culture from an outpatient in the surrounding community who was treated for pinkeye.

Is it likely that Ad14 has spread beyond these four states? Without hard data, Su is reluctant to speculate, but he suggests that doctors across the U.S. should pay special attention to patients who have severe or worsening colds.

"It is a germ that bears watching," Su says. "People have to be aware of this virus. It is becoming more common, and it does have the capability to cause severe illness in people of all ages. What puts people at risk of severe respiratory infection from Ad14 is not something we clearly understand yet."

Adenovirus Spreads Easily

There are 51 different adenovirus strains. In the 1960s, Gray says, adenovirus was considered a "rather innocuous childhood problem." That opinion changed when adenoviruses turned out to be responsible for huge outbreaks that caused severe disease and deaths among military recruits.

"Now we know adenovirus is really a big player and associated with chronic diseases," Gray says. "The latest condition to be associated with adenovirus is obesity. It's also implicated in heart infections, brain infections, and in some inflammatory diseases of the lung. It is a very interesting virus."

Adenovirus can spread from person to person via aerosolized droplets in sneezes and coughs. But it's also present in feces, and fecal-oral spread is common among young children. The virus can survive for weeks on contaminated surfaces. In the summer, there may be swimming-pool-related outbreaks.

The adenovirus incubation period is two to nine days. Different adenovirus strains behave differently, but outbreaks can be explosive.

A vaccine that protected against the Ad4 and Ad7 adenovirus strains nearly eliminated the U.S. military problem. But when its single manufacturer stopped making the vaccine, serious adenovirus outbreaks once again began to plague recruits.