ATLANTA, March 24 (UPI) -- The Centers for Disease Control and Prevention said Monday that officials now suspect a global outbreak of a mysterious pneumonia-like illness is caused by a new type of coronavirus, not paramyxovirus, as had been suggested previously.
"We are reporting today that our evidence indicates a new coronavirus is the leading hypothesis for the cause of this infection," CDC Director Dr. Julie Gerberding said during a news briefing.
Known forms of the coronavirus cause common colds and upper respiratory tract infections, but Gerberding said the evidence suggests "this may very well be a new or emerging coronavirus infection."
The illness -- called severe acute respiratory syndrome or SARS -- has infected 458 people in 14 countries and caused 17 deaths since it was first detected in February.
World Health Organization officials said previously that results in other laboratories indicated the cause of the illness might be a new virus in a family called paramyxoviridae, which includes measles and mumps.
Gerberding said although the CDC was not ruling out the possibility that paramyxo virus could be the cause of SARS, the agency's evidence "is very strong" supporting coronavirus.
"We also are very respectful of other labs that are collaborating in this investigation and it's very premature to assign a cause or make dogmatic statements about the etiology," she said.
CDC researchers have been able to grow a coronavirus from tissue samples from two SARS patients. Using a technique called polymerase chain reaction or PCR, they also have detected genetic evidence of the virus in lung and kidney tissue from one infected person.
In addition, three people showed evidence of developing an immune response to the virus after they became ill. Blood samples showed the patients had no antibodies to the virus when they first became ill, but they developed antibodies later as the disease progressed.
"We also are finding evidence of virus on genetic material in lung secretions, in lung tissue and in many, many other samples," Gerberding said.
"In scientific terms this is very strong evidence supporting coronavirus as the etiology," she said.
The CDC will continue to run more tests on more specimens from patients to confirm their hypothesis, she said. "We hope to be able to ascertain whether (coronavirus) really is related to the onset of disease and, if so, what is the relationship," she said.
Dr. Susan McLellan, an infectious disease specialist at Tulane University Health Sciences Center in New Orleans, urged officials to be cautious before accepting coronavirus as the cause.
"It certainly sounds pretty good but just like with the parmyxo virus, you have to confirm it in a variety of patients," McLellan told United Press International.
Coronaviruses occasionally can cause pneumonia, "but not with the severity that seems to be occurring in this outbreak," she said.
The CDC could not recommend specific medications to fight SARS, but Gerberding said the Department of Defense will be working with the agency to test anti-viral drugs against the potentially new coronavirus.
"There aren't any anti-virals that are thought to be particularly (effective) against coronaviruses, although some of the ones we have may be worth testing considering the severity of this outbreak," McLellan said.
So far, 39 people in 18 states have contracted SARS in the United States. Of these, 32 appear to have become infected while traveling in an affected country with the remaining seven consisting either of healthcare professionals who took care of these patients or family members who had close contact.
This pattern emphasizes the importance of quarantining patients who might be infected in order to limit the spread of the disease, Gerberding said. Healthcare workers taking care of SARS patients should wear respirators and gloves, avoid direct contact with bodily fluids and use appropriate hand hygiene to prevent transmission to other patients, she said.
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(Reported by Steve Mitchell, UPI Medical Correspondent, in Washington)
