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Turgida turgida is a common parasite of the stomach of the American opossum in Florida. Worms were usually found attached to the greater curvature of the corpus of the stomach. Ulcers always occurred at the site of the attachment. Large ulcers were associated with groups of adult parasites and were found in the oldest experimental infections. Turgida turgida fed on food within the stomach of the opossum and attached to the stomach wall when not feeding. Third-and fourth-stage larvae were found in opossums in Florida mainly from May to August suggesting that this is a major period of transmission.

The prevalence of Sarcocystis in white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) in South Dakota was determined through microscopic examination of tongue samples. The percentage of Sarcocystis infection for both species of deer was determined for prairies east of the Missouri River, west of the Missouri River, and Black Hills of western South Dakota. Sixteen percent (N = 62) of the white-tailed deer tongues from East River, 69% (N = 42) from West River, and 74% (N = 23) from the Black Hills were infected. Prevalence for mule deer was 88% (N = 24), 78% (N = 63), and 75% (N = 12) from East River, West River, and the Black Hills, respectively. Of 50 tongue samples obtained from both species of deer during a special antlerless deer hunt in the Black Hills in 1978, 66% were infected. Coyotes (Canis latrans), dogs (Canis familiaris), red foxes (Vulpes vulpes), a gray fox (Urocyon cinereoargenteus), bobcat (Felis rufus), and raccoon (Procyon lotor) were fed muscle from white-tailed deer and mule deer naturally infected with Sarcocystis to determine their role as definitive hosts. All coyotes, dogs, and the gray fox shed sporocysts, while none were recovered from the other animals. Sporocysts shed by coyotes were counted and concentrated into an inoculum and administered to a white-tailed deer fawn, which was necropsied 85 days after inoculation. Sections of heart, tongue, esophagus, diaphragm, and skeletal muscle were found to be heavily infected with sarcocysts, while sarcocysts were not detected in a control fawn.

A system to designate and define isolates of Trichinella spiralis is proposed. The designation gives the host from which the isolate was recovered, geographic origin, and year of recovery. Isolates of T. spiralis recovered from frozen muscles from four species of wild carnivores had low and different infectivity to laboratory mice. Viable larvae of T. spiralis were obtained from muscle samples of marten, wolverine, polar bear and arctic fox which had been frozen for 5, 6, 12 and 14 mo, respectively.

Sarcocysts were found by light microscopic examination of muscle in 199 (51%) of 390 white-tailed deer (Odocoileus virginianus) from the southeastern United States. Sarcocystis infections were detected more frequently in histologic sections of tongue (45%) than of heart (9%). Sarcocysts were significantly more prevalent in adult deer (54%) than fawns (26%) (P less than .01). Statistically significant differences in prevalence were not found in deer from different physiographic provinces or between sexes. Artificial digestion was more sensitive in detecting Sarcocystis infections than examination of histologic sections when both techniques were used to examine tongues of 35 deer. Three different size sporocysts, possibly representing at least two species of Sarcocystis, were recovered during feeding trials. Seven dogs (Canis familiaris) shed sporocysts 9 to 12 days after eating infected venison. Sporocysts measured 13.4-16.8 x 9.0-12.3 micrometers with an average measurement of 15.2 x 10.9 micrometers (N = 195). One of three cats (Felis catus) and one of two red foxes (Vulpes vulpes) first shed sporocysts of Sarcocystis 10 days after eating infected venison. Sporocysts from the cat measured 11.2-13.4 x 6.72-8.96 micrometers (avg 12.0 x 8.7 micrometers, N = 18), and those from the fox measured 11.2-15.7 x 9.0-11.2 micrometers (avg 13.6 x 10.2 micrometers, N = 7).

Samples of muscle from 4,773 specimens of 18 species of wild mammals from Ontario were examined for Trichinella. One of 12 mink (Mustela vison), 83 of 1,821 fisher (Martes pennanti) and 68 of 1,980 marten (Martes americana) had T. spiralis. Prevalences of infections by Trichinella were determined for fisher and marten from the Algonquin region, over a 10-yr period. Prevalences ranged from 0.9-9.2% in fisher and 1.3-8.7% in marten indicating that the parasite is well-established in the region. Prevalences of Trichinella increased with age of both fisher and marten. Intensities determined for the 1981-1982 sample ranged from 0.4-15.8 larvae/g for fisher and 22.4-159.7 larvae/g for marten. Higher intensities were not correlated with older hosts. Fisher and marten appeared to be the key hosts maintaining Trichinella in the Algonquin region, but transmission dynamics were unclear. Transmission may include an unidentified small rodent or other host and natural carrion-feeding.

Information on the blood parasites occurring in 3,866 anatids of 14 species collected from five locations in Alberta and Saskatchewan during 1976-80 is summarized. An overall prevalence of 26% with avian hematozoa was recorded. Leucocytozoon simondi was the most frequently encountered parasite, occurring in 17% of the ducks; Haemoproteus nettionis was observed in 11% of the birds while Plasmodium circumflexum and microfilariae (probably of Splendidofilaria fallisensis) occurred in only 2% and less than 1% of the sample respectively. Overall prevalence of infection in both immatures and adults was similar, although the sample was heavily biased in favor of the immature age class. While the overall prevalence of L. simondi was similar in both age classes, H. nettionis occurred twice as frequently in the adult birds. Infection prevalences of birds in the five geographic areas sampled were different and these differences are discussed. Prevalences also differed from year to year in birds from the various areas and these differences are attributed, in part, to the water levels encountered each year. Leucocytozoon simondi is considered a potentially limiting factor for waterfowl production in some areas of northern Alberta and Saskatchewan.

Blood smears were examined from 3,715 birds from four areas in the Republic of Panama. Hematozoa were present in at least 142 (50%) of the 281 species examined. An overall prevalence of 18% of the individual birds was noted: Haemoproteus 9%, Plasmodium 5%, Leucocytozoon less than 1%, Trypanosoma 2%, Atoxoplasma/Lankesterella less than 1% and microfilariae 3%. Prevalence in each of the four study areas varied from 13% to 28%. Distribution is analyzed by orders, families and individual species of Plasmodium are tabulated. New host records from 170 species of birds are recorded.