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.
Flowchart of poliovirus isolation protocol. This is an alternative test algorithm for poliovirus isolation and characterization, which is an adaptation of the World Health Organization (WHO) guidelines for environmental surveillance of poliovirus circulation [14]. *All five 25 cm2 flasks containing monolayers of L20B cells (that were not to be pooled for freezing) followed the same path. Tubes were pooled together.
