Recovery Efficiencies of Anthrax Spores and Ricin from Nonporous or Nonabsorbent and Porous or Absorbent Surfaces by a Variety of Sampling Methods

• NCJ Number: 224720
• Journal: Journal of Forensic Sciences Volume: 53 Issue: 5 Dated: September 2008 Pages: 1102-1107
• Author(s): Dody A. Frawley M.S.; Marian N. Samaan B.S.; Robert L. Bull Ph.D.; James M. Robertson Ph.D.; Alfred J. Mateczun M.D.; Peter C.B. Turnbull Ph.D.
• Date Published: September 2008
• Length: 6 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America
• Note: This is publication 07-05 of the Federal Bureau of Investigation.

Annotation

Spurred by the 2001 anthrax letter cases, which revealed the need to establish effective environmental sampling procedures, two studies were conducted for the purpose of establishing the best procedures for detecting the contamination of common surfaces after the release of environmentally stable bioaggressive agents such as anthrax spores and ricin.

Abstract

The studies identified the relative recovery efficiencies of anthrax spores from the various surfaces tested by means of various methods. Although there was no point of direct comparison between the two studies, recoveries with moist swabs (polyester in one study and cotton in the other study) from nonporous, nonabsorbent surfaces (plastic, glass, desktop formica, and metal) were not significantly different, indicating equivalent performances in the two studies. Contact plates, with mean retrieval rates of 27-54 percent, performed better than other methods by a wide margin for flat nonporous, nonabsorbent surfaces. Technically, contact plates also performed better than other methods on porous, absorbent materials (carpet, brick, and synthetic cloth); however, actual recoveries by this method were low (less than 7 percent). For both anthrax spores and ricin, dry devices (swabs, wipes, and Trace Evidence Collection Filters) had universally poor retrieval efficiencies, with no significant differences between them. Among moistened devices (wipes, swabs, and sample collection and recovery devices), wipes were generally best, albeit with significant cross-over among individual readings (highest mean recoveries for anthrax spores and ricin off plastic were 5.5 percent and 2.5 percent, respectively). The first study was concerned with direct comparison of recovery methods from three surface types. The second study focused on refining the contact plate for quantitative retrieval of anthrax spores. The types, sources, and preparation of the spores are described. 6 tables, 2 figures, and 21 references