[Progress and prospect in research on laboratory tree shrew in China].

We outline the historical research on the laboratory tree shrew in China and discuss its current research trends. Five key aspects of applied research are emphasized in this review, including quality control standards for laboratory tree shrews, the establishment of an inbred colony, commercial preparation of major molecular and cellular research tools, further research on tree shrew models for human diseases, and the establishment of the tree shrew seed institution at state level.

Sarcocystis tupaia, sp. nov., a new parasite species employing treeshrews (Tupaiidae, Tupaia belangeri chinensis) as natural intermediate hosts.

The range of vertebrates that serve as intermediate hosts for parasites in the genus Sarcocystis remains incompletely defined. Here, we provide the first report of infections in treeshrews, describe the morphology of encysted parasites using light and transmission electron microscopy, and place this agent within a phylogenetic context by sequencing and comparing its 18S ribosomal DNA to that of related parasites. Muscle infections were diagnosed in four of 45 wild treeshrews captured in the vicinity of Kunming, Yunnan Province, Mainland China. Thread-like cysts (10.773+/-2.411mm in length, 0.106+/-0.009mm in width) had walls (0.538-0.746microm thick) that lacked perpendicular protrusions. The interior of the cyst was packed full with cyst merozoites, the shape of which was typical of Sarcocystis. The primary cyst wall consisted of a thin membrane supported by osmiophilic material, 31-60nm in thickness. The ground substance was about 105-526nm thickness. Cysts conformed to typical of 'type 1' sarcocysts. Freshly examined and frozen specimens did not differ in their cyst wall structure, however, the appearance of bradyzoites did differ: the conoid, rhoptries and micronemes were all visible in fresh bradyzoites; in stored bradyzoites, by contrast, the rhoptries appeared smaller, and although the conoid was visible, the micronemes were not. 18S rRNA gene was distinct from any previously reported sequence in GenBank. Their genetic and morphological uniformity suggest that these parasites, derived from treeshrews, represent a single biological species, Sarcocystis tupaia, sp. nov.