Lower HIV levels among injection drug users in
Western US - Black Tar
Heroin 27 Jan 2004
Contact: Jeff Sheehy
University of California - San Francisco
UCSF researchers have found that use of black tar heroin by injection
drug users in West Coast cities accounts for a dramatically lower
percentage of IDUs in these locations who are infected with HIV.
The finding is based on comparison to East Coast cities, where powder
heroin is commonly used.
'In the early 1990s, about 40 percent of IDUs in New York City were
HIV-infected, while only about four percent of IDUs in Los Angeles were
infected with HIV. Yet in both cities, about 25 percent of gay men were
The solution to this discrepancy is found in the distribution and use of
black tar heroin and is due to its unique chemical properties,' said the
study's lead author, Daniel H. Ciccarone, MD, MPH, assistant professor
in the UCSF departments of family and community medicine and of
anthropology, history and social medicine.
The study, published in the December 2003 issue of Substance Use &
Misuse, examined data from the Drug Enforcement Agency (DEA) on the
predominant types of heroin used in 20 US cities from 1990 to 1993.
This data was compared with estimates published in the American Journal
of Public Health in 1996 of the percentages of both IDUs and gay men
infected with HIV in the same cities during the same time frame.
In cities west of the Mississippi, black tar heroin - a dark, gummy,
resinous substance from Mexico - is the type of heroin predominately
available. On the East Coast, white and light brown powder heroin from
South Asia and South America is the type predominately available.
Study findings showed the percentage of IDUs infected with HIV was
sharply lower in cities where black tar heroin use predominated compared
to cities where powder heroin use predominated, a pattern that was not
mirrored in the percentages of HIV-infected gay men.
Using ethnographic, clinical, epidemiological, and laboratory data,
researchers determined that black tar use by IDUs could lead to less HIV
transmission. First, before injecting black tar heroin, it must be
heated to about 165 degrees F, according to research done elsewhere.
This temperature is sufficient for killing the HIV virus, which limits
the likelihood of HIV transmission through sharing of drug preparation
paraphernalia, according to the UCSF researchers.
In addition, black tar heroin clogs syringes, they note. Frequent
rinsing and flushing is required, reducing the amount of residual blood
and HIV virus present.
'In California, injectors are constantly complaining that their needles
clog. They almost always rinse their syringes immediately after shooting
up in order to keep them from jamming. The grounds of shooting
encampments and the walls of shooting galleries are wet from the water
that they squirt through their used needles. This is not the case in New
York, where white powder heroin does not 'gum up' needles. Laboratory
studies have shown that rinsing syringes copiously with water works well
to clean out HIV,' said the study's co-author, Philippe Bourgois, PhD,
professor and chair of the UCSF Department of Anthropology, History, and
Moreover, using gummy black tar heroin ruins syringes, leading to
increased turnover of syringes. 'Black tar injectors rarely report using
a single syringe more than five times, while powder heroin users claim
many more uses out of their syringes,' said Ciccarone.
The study also noted that injecting black tar heroin leads rapidly to
venous sclerosis - a condition that results in the loss of veins for
Thus, black tar heroin users are much quicker to move to subcutaneous
and intramuscular injecting. Studies have shown that these are not as
efficient as venous injection for transmitting HIV.
'We believe that we have solved this longstanding epidemiological puzzle
thanks to multidisciplinary science and data from the DEA on the types
and distribution patterns of heroin. This data is valuable to public
health authorities. Consider that if powder heroin were to become more
widely available on the West Coast, public health agencies would need to
prepare for the possibility that currently successful interventions to
prevent HIV transmission among IDUs may lose much of their
effectiveness,' said Ciccarone.
'Likewise, while black tar heroin use becoming predominate on the East
Coast may positively affect HIV transmission rates among IDUs, public
health officials will need to be aware in order to prepare for the
different risks associated with its use. The increased intramuscular
injecting associated with black tar heroin use leads to higher rates of
abscesses, wound botulism, tetanus, gas gangrene, and necrotizing
fasciitis. In fact, soft tissue infections are the number one
medical/surgical admission at San Francisco General Hospital,' said
Funding for this study was provided by the National Institute on Drug