Context.— Wound botulism (WB) is a potentially lethal, descending, flaccid, paralysis
that results when spores of Clostridium botulinum
germinate in a wound and elaborate neurotoxin. Since 1988, California has
experienced a dramatic increase in WB associated with injecting "black tar"
heroin (BTH), a dark, tarry form of the drug.
Objective.— To identify risk factors for WB among injecting drug users (IDUs).
Design.— Case-control study based on data from in-person and telephone interviews.
Participants.— Case patients (n=26) were IDUs who developed WB from January 1994 through
February 1996. Controls (n=110) were IDUs newly enrolled in methadone detoxification
programs in 4 counties.
Main Outcome Measures.— Factors associated with the development of WB.
Results.— Among the 26 patients, the median age was 41.5 years, 15 (58%) were
women, 14 (54%) were non-Hispanic white, 11 (42%) were Hispanic, and none
were positive for the human immunodeficiency virus. Nearly all participants
(96% of patients and 97% of controls) injected BTH, and the mean cumulative
dose of BTH used per month was similar for patients and controls (27 g and
31 g, respectively; P=.6). Patients were more likely
than controls to inject drugs subcutaneously or intramuscularly (92% vs 44%, P<.001) and used this route of drug administration more
times per month (mean, 67 vs 24, P<.001), with
a greater cumulative monthly dose of BTH (22.3 g vs 6.3 g, P<.001). A dose-response relationship was observed between the monthly
cumulative dose of BTH injected subcutaneously or intramuscularly and the
development of WB (χ2 for linear trend, 26.5; P<.001). In the final regression model, subcutaneous or intramuscular
injection of BTH was the only behavior associated with WB among IDUs (odds
ratio, 13.7; 95% confidence interval, 3.0-63.0). The risk for development
of WB was not affected by cleaning the skin, cleaning injection paraphernalia,
or sharing needles.
Conclusions.— Injection of BTH intramuscularly or subcutaneously is the primary risk
factor for the development of WB. Physicians in the western United States,
where BTH is widely used, should be aware of the potential for WB to occur