Among prion infections, two scenarios of prion spread are generally observed: 
(i) early lymphoid tissue replication or (ii) direct neuroinvasion without 
substantial antecedent lymphoid amplification. In nature, cervids are infected 
with chronic wasting disease (CWD) prions by oral and nasal mucosal exposure, 
and studies of early CWD pathogenesis have implicated pharyngeal lymphoid tissue 
as the earliest sites of prion accumulation. However, knowledge of chronological 
events in prion spread during early infection remains incomplete. To investigate 
this knowledge gap in early CWD pathogenesis, we exposed white-tailed deer to 
CWD prions by mucosal routes and performed serial necropsies to assess PrPCWD 
tissue distribution by real-time quaking-induced conversion (RT-QuIC) and 
tyramide signal amplification immunohistochemistry (TSA-IHC). Although PrPCWD 
was not detected by either method in the initial days (1 and 3) postexposure, we 
observed PrPCWD seeding activity and follicular immunoreactivity in 
oropharyngeal lymphoid tissues at 1 and 2 months postexposure (MPE). At 3 MPE, 
PrPCWD replication had expanded to all systemic lymphoid tissues. By 4 MPE, the 
PrPCWD burden in all lymphoid tissues had increased and approached levels 
observed in terminal disease, yet there was no evidence of nervous system 
invasion. These results indicate the first site of CWD prion entry is in the 
oropharynx, and the initial phase of prion amplification occurs in the 
oropharyngeal lymphoid tissues followed by rapid dissemination to systemic 
lymphoid tissues. This lymphoid replication phase appears to precede 
neuroinvasion.IMPORTANCE Chronic wasting disease (CWD) is a universally fatal 
transmissible spongiform encephalopathy affecting cervids, and natural infection 
occurs through oral and nasal mucosal exposure to infectious prions. Terminal 
disease is characterized by PrPCWD accumulation in the brain and lymphoid 
tissues of affected animals. However, the initial sites of prion accumulation 
and pathways of prion spread during early CWD infection remain unknown. To 
investigate the chronological events of early prion pathogenesis, we exposed 
deer to CWD prions and monitored the tissue distribution of PrPCWD over the 
first 4 months of infection. We show CWD uptake occurs in the oropharynx with 
initial prion replication in the draining oropharyngeal lymphoid tissues, 
rapidly followed by dissemination to systemic lymphoid tissues without evidence 
of neuroinvasion. These data highlight the two phases of CWD infection: a robust 
prion amplification in systemic lymphoid tissues prior to neuroinvasion and 
establishment of a carrier state.