Trypanosoma cervi sp. n. is described from 22 trypomastigote syntypes from the blood of elk, Cervus canadensis, in North America (type locality: Wyoming). The blood trypomatigotes of T. cervi are compared with various culture forms: epimastigotes in 22 to 25 C NNN cultures; trypomastigotes in 37 C NNN cultures; and trypomastigotes from CAM chick embryo (10-day) cultures. Trypanosoma cervi is differentiated on morphological grounds from the cosmopolitan bovine species, T. theileri, and from T. ingens and T. mazamarum. Transmission of T. cervi to cattle was attempted using infected elk blood. No trypanosomal stages were recovered when recipients were examined by blood culture. The findings support the morphological data that T. cervi is distinct from T. theileri.

Twenty-nine (64.4%) of 45 reindeer, Rangifer tarandus, examined over a two-year period were infected with trypanosomes. Trypomastigotes and dividing epimastigotes were found in the blood of fawns, cows, and bulls. Morphometric analysis of bloodstream trypomastigotes from reindeer and comparison of these parasites with similar stages of trypanosomes from elk, mule deer, and white-tailed deer from the contiguous United States proved them conspecific; the trypanosomes from these members of the Cervidae are identified as Trypanosoma cervi Kingston & Morton, 1975. This is the first report of trypanosomes from reindeer. No pathogenic effects are known to be caused by these parasites. RYPANOSOMES have never been reported from reindeerReceived 10 VI 81; accepted 7 V 82

Further studies on moose revealed trypanosomes in two captive moose (Alces alces shirasi) and in 4 of 7 free-ranging moose in Wyoming by blood culture. Two free-ranging moose from Utah were negative. One of two additional captive moose calves was positive for trypanosomes. Trypanosomes also were detected in blood cultures of 8 of 39 American Bison (Bison bison) being brought into Wyoming from Nebraska. Nineteen additional bison were negative for trypanosomes by blood cultures. Identification of species was not possible due to the failure to obtain bloodstream trypomastigotes from this host. Trypanosomes were recovered from 8 of 57 pronghorn antelope (Antilocapra americana). This is the first report of Trypanosoma sp. from bison and from pronghorn; the trypanosome from moose was identified as Trypanosoma cervi from bloodstream trypomastigotes. In 1978, natural transplacental transmission of trypanosomes was found to occur in 1 of 15 mule deer (Odocoileus hemionus) fetuses, examined near term by blood culture. No trypanosomes were found in 18 male deer fetuses examined in 1979. Of 100 free-ranging elk from western Wyoming examined by blood culture in 1979, 71 were infected. These data are compared with data from 1973-74.

Mensural values of blood stream stages and cross-transmission studies defined the trypanosome species from mule deer, Odocoileus hemionus, as con-specific with Trypanosoma cervi, the trypanosome found in elk from the same locality. Trypanosomes were found in eight mule deer sampled in the spring and eight sampled in the winter in southeastern Wyoming.

Blood samples were collected from captive and free-ranging elk (Cervus canadensis), mule deer (Odocoileus hemionus), white-tailed deer, (Odocoileus virginianus), black-tailed deer (Odocoileus hemionus columbianus), pronghorn (Antilocapra americana), moose (Alces alces), and bighorn sheep (Ovis canadensis) for cultural evidence of Trypanosoma sp. infection. Eleven of 188 (12%) hunter-killed elk, 22 of 37 (59%) free-ranging elk, and 79 of 119 (66%) captive elk were culture positive in 1973-74. Parasitemia in adult captive elk showed seasonal variation. Other captive or live-trapped animals found positive included 16 mule deer, two white-tailed deer, and one black-tailed deer. No pronghorn, moose, or bighorn sheep were positive. A 0.25 ml inoculum of elk blood was sufficient to give positive culture results. Small sample size may have contributed to negative results from elk trapped in March 1973.