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.
Viral burden in lymphoid tissues. The viral burden in lymphoid tissues 5 weeks after challenge, as determined by competitive RT-PCR, is expressed as the number of copies of viral RNA per microgram of total RNA. Symbols: ▪, Axillary ganglion; , spleen; □, thymus.
