DOCTOR'S VIEW ARCHIVE
Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR
A rare strain of a cold virus, known as adenovirus type 14 (Ad14), has caused severe and even fatal respiratory illness in healthy children and adults. Infection with the virus seems to be becoming more common in the United States, according to officials from the U.S. Centers for Disease Control and Prevention (CDC). This virus is different from other adenoviruses that cause the common cold in that it may produce an unusually severe illness requiring intensive medical care. Although the Ad14 strain was identified in the 1950s, the variant that was isolated in 2006 and 2007 is genetically different from the original Ad14, suggesting that the viral genetic material has undergone mutations (changes) that have resulted in the increased severity of infections with Ad14.
As of November 2007, four known outbreaks of Ad14 had been reported in the U.S., beginning with the infection and death of a healthy infant in New York City in May 2006. Subsequent outbreaks occurred in 2007 in Oregon, Texas, and Washington state, resulting in a total of 10 deaths due to pneumonia. Overall, 141 confirmed cases of the infection occurred in these four outbreaks. The deaths occurred in previously healthy adults and children as well as in people with chronic conditions.
There are 51 known strains of adenovirus, a common and highly contagious virus type that does not always cause symptoms in healthy people. In other cases, adenoviruses may be responsible for conditions ranging from the common cold to conjunctivitis (pink eye), gastrointestinal infections, urinary tract infections, or skin rash. It has also been associated with infections of the heart and brain. Symptoms, if present, appear anywhere from two days to two weeks after exposure to the virus.
Adenovirus infection is extremely contagious. The infection can be spread by aerosolized droplets in air (from sneezing or coughing) or by fecal-oral contamination. Spread from contamination with feces is a common route for transmission in children. The virus is able to survive for weeks on surfaces that have been contaminated.
There is no vaccine available for adenovirus. A previous vaccine that protected against adenovirus serotypes 4 and 7 and was used to help control outbreaks of these strains in military barracks is no longer available. However, a new vaccine against these two types is in development. Still, the new vaccine would not protect against the highly virulent Ad14 strain.
While infection with the Ad14 virus is rare, anyone who has a cold or respiratory infection that is getting progressively worse should contact their health-care provider. Parents should monitor symptoms in children with colds or respiratory infections and seek medical attention if the condition is only getting worse. Health-care providers can send samples for testing to determine whether the illness is due to Ad14. Identification of Ad14 infections can help ensure that those affected receive intensive medical care and support.
Reference: Mor Mortal Wkly Rep CDC Surveill Summ 2007;56:1181-1184.
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