Full text
PDFPage 2444
. 1991 Aug;57(8):2444. doi: 10.1128/aem.57.8.2444-2444.1991
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.