Pattern of injecting drug uses and HIV-1 infection: analysis from needle exchange program.

Contents of exchanged needles/syringes were analyzed to examine: i) the prevalence of HIV-1 infection among injecting drug users (IDU's), and ii) the classes of drugs injected by the population. A needle exchange program in Puerto Rico (PR) was initiated under the auspices of the PR Department of Health and is currently being administered by the Community Research Initiative of Puerto Rico, Inc. Serological tests for human immunodeficiency virus type 1 (HIV-1) were performed with 387 samples with clearly visible amounts of blood, which were chosen randomly from the needle exchange program of the San Juan Metropolitan area on the north coast, and also of the Mayaguez area on the west coast of the island. In addition, 200 syringes without visible amount of blood were also randomly chosen, their contents were extracted with acidified methanol and analyzed by gas chromatography-mass spectrometry (GC/MS) for drug content. One hundred and ninety four of the samples (58%) were confirmed to be positive for HIV-1. Four samples contained heroin alone, 190 were positive for cocaine and 2 indicated simultaneous use of both heroin and cocaine. In contrast to existing literature, based mostly on self-description, which indicates widespread use of heroin and cocaine mixture ("speedball") among IDU's, our physical evidence suggests that a large majority of IDU's in PR currently inject cocaine but not heroin; and also that mixed drug use is rather rare. Reliability of self-described information may need to be re-evaluated.