Is HIV unique or merely different?

The HIV epidemic is similar to previous human epidemics, and our early responses to the HIV epidemic have likewise been similar. Furthermore, HIV is similar to other single-stranded RNA viruses in its evolution. Like other RNA viruses, HIV has a high mutation rate and thus evolves rapidly. This rapid evolution may make it difficult to develop a successful vaccine against HIV, and perhaps may also limit the usefulness of drugs because of the appearance of resistant mutants. However, most of the variation in HIV nucleotide sequences is neutral, not adaptive. Other viruses in the same retrovirus subfamily as HIV (lentiviruses) are also successful pathogens in animals and are difficult to control without the added problem of the social factors that exist for HIV. These social factors involved in HIV transmission make HIV hard to control by usual public health measures. The prevalence of syphilis and hepatitis B in the United States shows that neither a successful drug treatment nor an effective vaccine is sufficient to stop some infectious diseases when social factors are involved. For these reasons, I conclude that the HIV/AIDs epidemic is different, but not unique.