Killer Cold Virus Caused 10 Deaths

Killer Cold Virus Caused 10 Deaths
By Michael Smith, Senior Staff Writer, MedPage Today
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine.
November 16, 2007
ATLANTA, Nov. 16 -- Clinicians should keep their eyes peeled for a mutated form of adenovirus 14 that has caused at least 10 deaths, most of them among adults, the CDC warned.

Noting that control of adenovirus is "challenging," the CDC urged health care practitioners to take extra care if they suspect an adenovirus infection and to follow the 2003 guidelines for pneumonia care.
Action Points

* Explain to interested patients that adenovirus infections are usually not life-threatening among adults, although they can be deadly in newborns, the elderly, and those with an underlying medical condition.

* Note that this report suggests that a strain of adenovirus now circulating is preferentially causing mortality among adults.

But the agency -- calling the infection "uncommon" -- did not suggest any special precautions for the general public.

Fifty-one adenoviruses are known and most cause non-life-threatening disease in adults, although severe disease -- including pneumonia and gastrointestinal disease -- can occur in newborns, the elderly, and those with an underlying medical condition.

The new strain of adenovirus 14 differs in that most of its victims have been otherwise healthy adults, CDC officials said.

"What really got people's attention is these are healthy young adults landing in the hospital and, in some cases, the ICU," said John Su, M.D., Ph.D., of the CDC.

But the first case that came to the CDC's attention was a 12-day-old infant who died in a New York hospital in May 2006. The baby girl was full-term and the delivery was uncomplicated, the agency reported.

Postmortem examination found adenovirus 14, as well as chronic inflammatory cells with intranuclear inclusions, in the lungs, consistent with adenoviral bronchiolitis and acute respiratory distress syndrome.

The strain would prove to be genetically identical to isolates found in three clusters of adenovirus 14 disease over the following 18 months, the CDC said, but different in some respects from the reference strain, first isolated in 1955.

The finding suggests "the emergence and spread of a new [adenovirus 14] variant" in the U.S., the agency said in the Nov. 15 issue of Morbidity and Mortality Weekly Report.

The later clusters were reported in 2007 in Oregon, Washington state, and Texas, the CDC said.

The largest outbreak took place from Feb. 3 to June 23 at Lackland Air Force Base in Texas, where 27 patients were sent to the hospital with pneumonia, including five who were admitted to the intensive care unit.

One of the five required extracorporeal membrane oxygenation for about three weeks and ultimately died. Medical personnel collected throat swabs from 16 of the 27 -- including the intensive care patients -- and all tested positive for the virus.

Also, during that period, medical personnel collected and tested 423 specimens associated with an outbreak of febrile respiratory infection, of which, 268 tested positive for adenovirus. A little less than half of the specimens (44%) were also serotyped and 90% were adenovirus 14.

The deadliest outbreak, identified retrospectively, occurred in Oregon, after a local clinician reported multiple patients admitted to a single hospital for pneumonia over a five-week period in March and April.

Of the 17 specimens obtained, 15 were positive for adenovirus 14, the CDC said, leading Oregon public health authorities to review records from virology labs and find 68 people who tested positive between Nov. 1, 2006, and April 30, 2007.

Of those, 50 isolates could be serotyped and 31 were adenovirus 14, the CDC reported, while 15 were another serotype and four were not actually adenovirus.

Review of medical records for 30 of the 31 with adenovirus 14 showed that 22 patients required hospital care, 16 required intensive care, and seven died, all from severe pneumonia. Most of the dead were adults, but one infant also died.

In contrast, only two of the 13 non-type 14 patients whose charts were available needed hospital care, none needed intensive care, and none died. (See: IDSA: Outbreak of Severe Pneumonia Traced to Adenovirus 14)

In Washington, officials reported four patients -- one with AIDS and three with chronic obstructive pulmonary disease -- with cough, fever, or shortness of breath between April 22 and May 8, 2007.

Three required intensive care and mechanical ventilation for severe pneumonia, and after eight days of hospital care, the AIDS patient died, while the other patients recovered.

All four tested positive for adenovirus and the three with isolates available for serotyping were shown to have adenovirus 14.

The CDC urged clinicians to follow its 2003 guidelines for pneumonia care. Among other things, the guidelines suggested changes in ventilation practices:

* Orotracheal rather than nasotracheal tubes should be used in patients who need mechanically assisted ventilation.
* Noninvasive ventilation should be used to reduce the need for and duration of endotracheal intubation.
* The breathing circuits of ventilators should be changed when they malfunction or are visibly contaminated.
* When feasible, an endotracheal tube with a dorsal lumen should be used to allow drainage of respiratory secretions.

Additional source: Morbidity and Mortality Weekly Report
Source reference:
"Acute Respiratory Disease Associated with Adenovirus Serotype 14 -- Four States, 2006-2007"MMWR 2007; 56(45): 1181-84.

http://www.medpagetoday.com/InfectiousDisease/URItheFlu/tb/7410