Aggressive HIV Strain Appears to Be Isolated Case

A presentation Monday at the 3rd International AIDS Society Conference on HIV Pathogenesis and Treatment in Rio de Janeiro refuted the notion of an outbreak of a new, highly aggressive and multiple drug-resistant HIV strain in New York City. On Feb. 11, the New York City Department of Health issued a press release warning of a man infected by such a strain. Reports on the case followed in the medical journal Lancet and elsewhere.

The apparent source for the New York man's HIV infection is a Connecticut man whose clinical course is typical of AIDS patients with his disease, behavior, and medical compliance, reported Dr. Gary Blick, medical and research director of Circle Medical LLC, Norwalk, Conn. "He is not a rapidly progressive patient," said Blick.

The Connecticut patient carries an HIV strain that is a 99.5 percent genetic match to that of the New York patient, said Blick. The Connecticut man's life partner carries an HIV strain that is a 98.5 percent match, and has a similarly unremarkable disease course. The patients involved were able to identify each other visually and confirm they had previously had anal intercourse, said Blick.

The Connecticut patient's virus has a replication capacity of 41 percent, and since he has become treatment compliant, his CD4 levels and viral load have remained stable. In contrast, the New York man's virus showed a viral replication capacity of 136 percent; he was infected for only four months before progressing to AIDS. The New York patient also had a history of unprotected sex and multiple partners, often while using crystal methamphetamine.

Blick hypothesized that the rapid course and drug resistance in the New York patient was due to unusual host factors, including an unusually active sex life and heavy drug use. It could also be possible that the virus strain is less responsive to treatment or a combination of the two factors, he said. In addition, said Blick, the widespread practice of "poz-to-poz" unprotected sex may be riskier than previously assumed.

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