Related story in Agricultural Research magazine, May 1999

Shrub-Derived Latex Products Block Viruses, Bacteria

Surgical gloves, condoms or other products made from the natural rubber latex of a southwestern desert shrub called guayule are an effective barrier against disease-causing bacteria and viruses.

That's according to preliminary tests with the high-quality, hypoallergenic latex made from guayule (pronounced why-YOU-lee). The research was done by Katrina Cornish of USDA's Agricultural Research Service in Albany, Calif., and C. David Lytle, recently retired from the U.S. Food and Drug Administration.

The tests provide new evidence that medical, home and industrial products made from guayule latex may offer a safe, practical alternative for the estimated 20 million Americans allergic to latex products made from the most common source, the Brazilian rubber tree.

Prototype patient-examination gloves and condoms made of guayule latex passed standard virus-permeability tests, according to the scientists. Those tests determined that a test virus, especially chosen for its small size, could not slip through the guayule latex. Known as phi X174, the virus is smaller than bacteria and is the same size, or smaller than, human pathogenic viruses such as HIV, hepatitis B and herpes simplex.

The prototype gloves and condoms used for the tests were made of latex from Arizona-grown guayule. They were the same thickness as commercially produced gloves and condoms made of natural latex from the Brazilian rubber tree. The findings will appear in the December 5 issue of the Journal of Biomedical Materials Research.

In 1994, Cornish's team was the first to show that guayule latex is free of the allergens that can cause severe reactions such as anaphylactic shock or even death.

Scientific contact: Katrina Cornish, Crop Improvement and Utilization Research Unit, ARS Western Regional Research Center, 800 Buchanan St., Albany, CA 94710; phone (510) 559-5950, fax (510) 559-5777, kcf@pw.usda.gov.