Experimental chronic wasting disease in wild type VM mice.

Chronic wasting disease (CWD) is a naturally occurring prion disease in North American deer (Odocoileus species), Rocky mountain elk (Cervus elaphus nelsoni) and moose (Alces alces). The disease was first confirmed in the Republic of Korea in 2001, and subsequent cases were diagnosed in 2004, 2005 and 2010. The experimental host range of CWD includes ferrets, several species of voles, white-footed mice, deer mice and Syrian golden hamsters. In addition, CWD was transmitted to the transgenic mouse over-expressing elk or deer prion protein efficiently, but not to wild type mouse. Here, we report the experimental transmission of elk CWD to conventional VM/Dk mice reaching 100% attack rate after second passage. The CWD-prion-affected wild type mice will be a useful model for future CWD studies.

Strain characterization of the Korean CWD cases in 2001 and 2004.

Chronic wasting disease (CWD) has been recognized as a naturally occurring prion disease in North American deer (Odocoileus species), Rocky Mountain elk (Cervus elaphus nelsoni) and moose (Alces alces). The disease was confirmed only in elk in the Republic of Korea in 2001, 2004 and 2005. Epidemiological investigations showed that CWD was introduced via importation of infected elk from Canada between 1994 and 1997. In spite of the increasing geographic distribution and host range of CWD, little is known about the prion strain (s) responsible for distinct outbreaks of the disease. We carried out strain characterization, using transgenic mice overexpressing elk prion protein, including clinical assessment, pathological examination and biochemical analyses, in brain tissues derived following primary through tertiary transmissions. The final incubation period was shortened to approximately 130 dpi due to adaptation. Biochemical profiles remained identical between passages. Lesion profiling in recipient mice brains showed similar patterns of vacuolation scores and intensity. It is clear that there were no biochemical or histopathological differences in Korean CWD cases in 2001 and 2004, suggesting a single strain was responsible for the outbreaks.