Epidemiology of Emerging 3-DCR HIV Case Cluster
Recombinomics Commentary
February 15, 2005
>> The news last weekend that a New York City patient had contracted a rare strain of HIV--one that resisted several drugs and was linked to rapid onset of AIDS--had a familiar ring to Dr. Julio Montaner of Vancouver.
In 2001 Montaner made news in British Columbia by announcing he and colleagues had identified a potential HIV "superbug" in two newly infected patients. As with the New York case, the Vancouver patients developed AIDS within months after infection and had a virus that was resistant to three anti-HIV drugs. <<
Although there are similarities between the Vancouver cluster and the NYC cluster, there may be important differences. Establishment of a "superbug" has two minimal requirements. One is a change in the genetic structure of the virus and the other is efficient transmission. Since the Vancouver cluster was in 2001, it would appear that transmission was limited. Moreover, although the Vancouver virus was associated with rapid progression and multi-drug resistances, its replication capacity (RC) was not disclosed.
Assuming that media reports are accurate, it seems that there are three individuals who are infected with a virus that has a similar profile. It is drug resistant, has CXCR4 tropism, and has a wild type RC. Viruses with all three properties are rare, hence only three individuals have been identified in the ViroLogic database.
Moreover, the three individuals are linked in time and/or space. The two in NYC were partners. The patient who was HIV+ first is not cooperating, so contacts and history are lacking. However, he probably infected his partner in the fall. The second NYC case is cooperating, but he had as many as 100-200 partners in the fall and doesn't know the names of many. The patient in San Diego also tested positive in the fall. However, it is unclear if there is any physical linkage between the San Diego case and the two cases in NYC.
Thus, the current cluster is unique because all three patients are infected with a virus with three properties that are not normally found together. In addition, the San Diego patient may not have had a physical link with the two NYC patients.
More information on the relationship between the three cases, as well as contact tracing, can provide more information on transmission and progression.
At this point, however, the cluster is more than an isolated case.
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