In a few African cities, including Dar es Slam, Tanzania, and Mombasa, Kenya, reports are emerging of heroin addicts injecting themselves with another addicts blood to share a high, or avoid the pangs of withdrawal, the New York Times reports. This practice, called flashblood or flushblood, creates the highest risk of contracting AIDS and hepatitis. According to Dr. Nora D. Volkow, director of the National Institute on Drug Abuse, whose researchers discovered this practice, it’s a relatively small group who does it, but “they are vectors for H.I.V. because they support themselves by sex work.” The practice was first described in a short letter to the British Medical Journal five years ago by Sheryl A. McCurdy of the University of Texas in Houston, who recently published a paper on the topic. In most East African countries including Tanzania and Kenya, only 3 to 8 per cent of adults are infected with the AIDS virus, but among those who inject heroin, it’s far higher: in Tanzania, about 42 per cent of addicts are infected. It’s not known whether people can actually get high from injecting less than a teaspoon of another’s blood; while addicts report being high, some believe it’s merely the placebo effect, or leftover drug in the syringe.