Aggressive HIV strain appears to be isolated case

By Karla Harby

RIO DE JANEIRO (Reuters Health) – Suggestions that a new,
highly multidrug resistant and rapidly progressing strain of
HIV has evolved in New York City and could become widespread
have been refuted by the discovery of the probable patient
source of the virus, according to a presentation here on Monday
at the 3rd International AIDS Society (IAS) Conference on HIV
Pathogenesis and Treatment.

The rapid progression to AIDS observed in a patient
discovered earlier this year led the New York City Department
of Health to issue a press release on February 11, 2005,
warning of a possible new, highly virulent and multidrug
resistant HIV strain. This was followed by reports in The
Lancet and elsewhere.

The apparent source patient, “Patient Zero,” is a resident
of Connecticut and his clinical course is typical of AIDS
patients with his disease, behavior and medical compliance,
said Dr. Gary Blick, medical and research director of Circle
Medical LLC, Norwalk, Connecticut.

The patient’s viral replication capacity is 41 percent, and
since he has become fully adherent to highly active
antiretroviral treatment (HAART), his CD4 levels and viral copy
number, measures of disease progression, have remained stable

“He is not a rapidly progressive patient,” Blick said. His
life partner’s disease course is similarly unremarkable.

By contrast, the New York City patient, whose disease so
alarmed clinicians, has shown a viral replication capacity as
high as 136 percent, Blick said. The patient was infected with
the virus about four months before he progressed to AIDS. That
patient has a history of extensive unprotected sex and multiple
partners, often while using crystal methamphetamine.

The Patient Zero identified in Connecticut carries a virus
that is a 99.5 percent genetic match to that of the New York
patient, Blick said. His life partner, who is also HIV
positive, has a genetic match of 98.5 percent.

In addition to the genetic evidence of virus transmission,
the patients involved were able to identify each other visually
and confirmed anal-receptive or anal-insertive intercourse,
Blick said.

Blick hypothesized that the rapid course and treatment
resistance experienced by the New York patient can be
attributed to unusual host factors, including an unusually
active sexual lifestyle and heavy use of crystal
methamphetamine.

It is also possible that this HIV strain is not as
responsive to treatment or that these two factors are
interacting to product this outcome, he said.

Blick added that the widespread practice of “poz-to-poz”
unprotected sex, in which sexual partners who are both HIV
positive fail to take precautions, may be riskier than
previously assumed.