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HIV is back in the news again — this time because a new strain has been identified. Genetically, this new HIV-1 virus resembles a simian immunodeficiency virus from gorillas, differentiating it from other HIV-1 viruses, which are closely related to chimpanzee viruses. Although there is not currently any evidence that this newly identified virus is more (or less) deadly than other HIV strains, the discovery of this virus should still serve as a warning to medical and public health practitioners. The warning is two-fold: first, there must be constant surveillance for variant HIV strains, and second, the testing and treatment needs of people infected with these variant viruses must not be ignored.

The worrying aspect of the discovery of this HIV variant, referred to as RBF168, is not that there is a new HIV strain per se but that this new HIV strain is not identifiable by all HIV tests. Luckily, screening tests still appear to identify this strain;  there are, however, problems with diagnostic tests including those that quantify viral loads. Moreover, the fact that this new strain seems to be identifiable by screening tests does not mean that all HIV strains are identifiable by these tests. It is also possible that there will be strains that can be identified by routine screening tests but, because of generic differences, will have higher false-negative rates than the common HIV strains. This fact exposes flaws in current HIV testing methods: because of limitations in testing, there are an unknown (and possibly unknowable) number of individuals with HIV who may not be treated for the disease until very late stages because of false-negatives in the testing process. Without data on the frequency of patients with AIDS who test negative for HIV by some or all virus detection methods, it is impossible to know the extent to which these variant HIV viruses will affect our ability to treat HIV/AIDS.

French scientists discovered the new HIV virus as part of a routine survey of genetic variability among HIV strains. The fact that such a survey is being done is a good indication that there is an active effort being made to identify emerging strains (and those not previously described). Such efforts should be expanded so that we can better gauge the prevalence of variant HIV viruses.

The introduction of dried blood spot testing has made this sort of monitoring more feasible for resource-poor settings. Typically used for HIV-testing of infants in resource-poor settings, dried blood spot testing eliminates the need for refrigeration during storage or shipping since the dried blood spots are relatively stable at room temperature. These blood spots can be shipped (internationally if need be) to laboratory facilities that have the equipment and lab technicians needed to test the blood spots for HIV. This technology would allow samples to be collected from many different sites and then processed in a central facility, making it easier to monitor the emergence of new HIV stains than if such testing were done in many locations.

It is not likely that there will be many HIV-“negative” individuals with AIDS, but public health practitioners must remember that these individuals exist when setting priorities in HIV testing and treatment programs, both in resource-poor and resource-rich settings. These HIV-“negative” individuals with AIDS have as much of a right to health as anyone else, and their needs should not be ignored. Unfortunately, medical and public health practitioners are not able to provide good (or even adequate) health care to everyone with HIV (or to HIV-negative individuals for that matter). Priorities must be set, and, unfortunately, at times trade-offs must be made. This is particularly true in resource-poor settings where HIV testing and treatment programs have limited or no coverage and where health systems in general are poor or practically nonexistent. The point is not that the problems associated with undetectable HIV strains must be solved immediately; rather, the point is that medical and public health practitioners must remember that such problems exist so that they can be addressed when the resources to do so are available.

In addition to serving as a warning, the identification of this new HIV virus also represents an opportunity for the scientific community to learn more about HIV. The RBF168 strain could be an excellent research tool because it differs considerably from other HIV-1 strains but still replicates efficiently in human cells. Analyzing the similarities and differences between RBF168 and other HIV-1 strains could give scientists a clearer picture of what characteristics of HIV are necessary for infection and disease progression. These analyses may not be the key to solving the current problems with HIV treatment, but a greater understanding of the virus definitely can’t hurt.

More information:

Nature Medicine: A new human immunodeficiency virus derived from gorillas (subscription)

Abbott Press Release: Increasing diversity of HIV strains impacts diagnostic test accuracy

F. R. Barin et al., “Monitoring HIV-1 subtype distribution,” in AIDS in Africa, M. Essex et al., eds, 2002. Preview available at http://books.google.com/books?id=KBvphLYVbDMC&pg=PA158&dq=AIDS+in+Africa,+M.+Essex+et+al#v=onepage&q=&f=false.

JAIDS: Dried blood spots improve access to HIV diagnosis and care for infants in low-resource settings

Journal of Clinical of Microbiology: Stability of dried blood spot specimens for detection of human immunodeficiency virus DNA by polymerase chain reaction

AIDS Research and Human Retroviruses: Detection of HIV type 1 env subtypes A, B, C, and E in Asia using dried blood spots: A new surveillance tool for molecular epidemiology