Alarm bells rang on Friday after health officials announced that "a highly resistant strain of a rapidly progressive" HIV had been diagnosed for the first time in a city resident.

But leading experts downplayed the alarm on Saturday.

"There is absolutely no evidence that this is a super virus," Dr Robert Gallo, director of the University of Maryland's Institute for Human Virology, said. Gallo is a co-discoverer of HIV, the virus which causes Aids.

The case was found in an unidentified man in his 40s with a history of unprotected gay sex. He developed Aids as early as two to three months after infection, and no more than 20 months, officials said.

Alert

Dr Thomas Frieden, commissioner of the New York City Development of Health and Mental Hygiene, called the case a potential major problem and the department issued an alert to hospitals and doctors to test for evidence of the strain of HIV.

The strain was resistant to three of the four classes of Aids drugs, and the concern was compounded by the fast onset of the disease, the health department said. 

"There is absolutely no evidence that this is a super virus"

Dr Robert Gallo,
Director of the University of Maryland's Institute for Human Virology

However, Gallo said it was prudent to pay attention to the case, but there was no evidence that the virus in question could be transmitted. He said the type of HIV that may be involved in the New York man's case can be particularly virulent, but it is difficult to transmit.
   
"This is not novel and the odds are enormous that the virus is not going to go anywhere," he said. What could change the assessment is if there were multiple cases of the virus being retransmitted, he said.

Dr John Moore, an Aids researcher at Cornell University's Medical School, was similarly cautious over the New York health department's announcement.
 
"Is this particular virus something that completely changes the equation? No, I don't think it does," he said. "Rather than a big super bug, it might turn out to be quite wimpy."