A strain of HIV that is highly resistant to almost all anti-retroviral drugs and which leads to the rapid onset of Aids has been detected in New York. Doctors and hospitals across the city have been placed on alert and told to test all new HIV cases for evidence of the strain.
The development has alarmed city health officials and was described as 'a scary phenomenon' by US AIDS expert David Ho. In addition, Robin Weiss, professor of viral oncology at University College, London, described the case as 'worrying'.
'We are going to have watch this very carefully,' Weiss said.
The strain has so far been found in only one person, a New York man in his mid-forties, but it is still causing considerable worry among health officials.
The man - who has not been named - is believed to have had unprotected sex with hundreds of partners. He complained of feeling ill in November, was found to be HIV positive in December and had contracted full-blown Aids in January.
'This a major potential problem,' Dr Thomas Frieden, of New York's department of health, told the New York Times. Frieden was speaking at a news conference, attended by dozens of AIDS experts and community leaders and which was hurriedly arranged on Friday.
Scientists have found the new strain is resistant to three of the four classes of drugs used to treat HIV and that this resistance was combined with a rapid transformation from HIV infection into AIDS. Both phenomena have been seen before, but not together.
The patient is now being treated using Enfuvirtide, which is still proving to be effective, though doctors warn that single-drug therapy is rarely effective against AIDS in the long term.
Health officials have warned that gay men are becoming increasing lax in their attitude to sexual health.
The success of anti-viral drugs, developed in the Nineties, has led many men to return to multiple-partner, unprotected sex - the habit that led to the disease's original spread through gay populations in the Eighties.
'Risky behaviour may be even more dangerous now since there is a chance of infection with a virus we may not be able to treat,' said Jay Dobkin, director of Columbia University's AIDS programme.
The patient with the new strain is also known to have been using crystal methamphetamine, a drug that can wipe out inhibitions and which has been linked to sex marathons.
'This was a disaster waiting to happen, particularly in communities where safer sex is not practised regularly and in light of people using drugs like crystal meth,' said Dr James Braun, of the US Physicians Research Network .
However, other experts counselled caution. 'This case is worrying, but it is important to bear in mind that people with the same strain of HIV can progress at very different speeds to AIDS symptoms,' said Lisa Power, of Britain's Terrence Higgins Trust.
This was reinforced by Maryland University's Robert Gallo, co-discoverer of HIV. It was already known that some patients progress rapidly from HIV infection to Aids but that occurred because they were highly susceptible to the disease and not because they had been infected with a resistant virus, he said.
John Moore, an AIDS researcher at Cornell University medical school, said the fact that only one case of a multiple drug resistant strain had been reported was important. 'If there was a cluster of these, that would be different,' he said.Most experts warned of the need for vigilance, however. 'It is certainly premature to say we have a new killer that is drug resistant going round,' said Weiss. 'On the other hand, it is clear we should be concerned and careful.'
Medicine and health
February 2003: Saving Grace - why 30m people with AIDS can't get the drugs they need
UN Aids report, November 2002
UN report into AIDS, July 2002
NHS Direct: HIV/AIDS
British HIV Association
Eldis HIV/AIDS guide
National AIDS Trust
Terrence Higgins Trust
Elton John Aids Foundation
Children with AIDS
Médecins Sans Frontières