Mother to Offspring Transmission of Chronic Wasting Disease Candace K. Mathiason, Amy V. Nalls, Kelly Anderson, Jeanette Hayes-Klug, Nicholas Haley and Edward A. Hoover Colorado State University, Department of Microbiology, Immunology and Pathology, Fort Collins, CO USA Key words: Chronic wasting disease, vertical transmission, muntjac deer We have developed a new cervid model in small Asian muntjac deer (Muntiacus reevesi) to study potential modes of vertical transmission of chronic wasting disease (CWD) from mother to offspring. Eight of eight (8/8) muntjac doe orally infected with CWD tested PrPCWD lymphoid positive by 4 months post infection. Six fawns were born to these CWD-infected doe. Six fawns were born to 6 CWD-infected doe; 4 of the fawns were non-viable. The viable fawns have been monitored for CWD infection by immunohistochemistry and sPMCA performed on serial tonsil and rectal lymphoid tissue biopsies. PrPCWD has been detected in one fawn as early as 40 days of age. Moreover, sPMCA performed on rectal lymphoid tissue has yield positive results on another fawn at 10 days of age. In addition, sPMCA assays have also demonstrated amplifiable prions in maternal placental (caruncule) and mammary tissue of the dam. Additional pregnancy related fluids and tissues from the doe as well as tissue from the nonviable fawns are currently being probed for the presence of CWD. In summary, we have employed the muntjac deer model, to demonstrate for the first time the transmission of CWD from mother to offspring. These studies provide the foundation to investigate the mechanisms and pathways of maternal prion transfer. PRION 2010 Meeting Report International Prion Congress: From agent to disease; September 8-11, 2010; Salzburg, Austria Volume 4, Issue 3 July/August/September 2010