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In January 1998 and 1999, two mass strandings of dolphins occurred in Wellfleet, Massachusetts. The strandings were composed of 97 and 53 animals, respectively. Tissues from 35 Atlantic white-sided dolphins (Lagenorhynchus acutus) from the 1998 stranding and 52 from the 1999 stranding were examined histologically. In the 1998 stranding, unidentified protozoal tissue cysts were seen in skeletal muscle from 11 of 28 (39%) dolphins. In addition, two dolphins had a protozoal tissue cyst in cardiac muscle. In the 1999 stranding, nine of 23 (39%) dolphins had the same protozoal tissue cysts in skeletal muscle. The identification of these protozoal tissue cysts as Sarcocystis sp. was confirmed by light and transmission electron microscopy. The high prevalence of sarcocysts in these dolphins suggests that they are likely intermediate hosts for previously undescribed Sarcocystis spp. The ultrastructure of the sarcocyst walls suggests that more than one species of Sarcocystis are present in dolphins.

Sarcocystis sp. schizonts were found in the cerebellum of a northern gannet (Morus bassanus), exhibiting neurologic signs, found on the Florida (USA) east coast. Based upon molecular characterization of DNA isolated from the brain of the gannet, this Sarcocystis sp. appeared to be closely related, if not identical, to an unnamed Sarcocystis sp. typified by isolates 1085 and 1086 collected from feces of a Virginia opossum (Didelphis virginiana) on the east coast of Florida. Because the life cycle of this parasite appears to be land based, urban waste discharge to marine/estuarine environments may be a source of infection for marine species.

Acute sarcocystosis was diagnosed in an adult female wild turkey (Meleagris gallopavo) that was collected from Early County (Georgia, USA) in February of 1998. Marked inflammatory lesions were seen in the heart, lung, and liver and were associated with protozoal schizonts and merozoites. The organisms were identified as Sarcocystis sp. (Acomplexa: Sarcocystidae) based on structure and antigenicity. Protozoa divided by endopolygeny, merozoites lacked rhoptries, and the organisms did not react to anti-S. falcatula antibodies but reacted to anti-S. cruzi antibodies.

Two bighorn sheep (Ovis canadensis) in New Mexico (USA) were found to be naturally infected with Elaeophora schneideri. An adult ram examined in 1997 in the Fra Cristobal Mountains had 26 nematodes in the carotid and iliac arteries, and microfilariae were present in the skin, nasal mucosa, brain, and lungs. This ram was markedly debilitated prior to euthanasia and extensive crusty, scabby lesions were observed on its head. In 1998, a yearling ewe found dead adjacent to Watson Mountain near the Gila Wilderness area was found to have 13 nematodes present in its heart. This is the first report of E. schneideri in bighorn sheep, and we suggest that bighorn sheep are susceptible to E. schneideri infection wherever they coexist with mule deer (Odocoileus hemionus hemionus) and appropriate tabanid vectors.

A shortfin mako shark (Isurus oxyrinchus) caught in 1996 by sportfishermen in Long Island (New York, USA) had many granulomas containing larval nematodes. Granulomas were present in the myocardium, spleen, pancreas, stomach, spiral intestine, hematopoietic tissue within the anterior kidney, and in the branchial septum and primary lamellae of the gills. Epicardial hyperplasia and granulomatous myocarditis were associated with the larvae. Although identification of the larvae was impossible due to lack of distinct morphological features, they resembled dracunculoid larvae previously reported from sharks.

Thirty-seven subadult and adult coyotes (Canis latrans), collected August 1992 through December 1996 from a coastal foothill area in northern California (USA), were examined for adult heartworm (Dirofilaria immitis). During 1992 through 1993, at the end of a 6 yr drought, none of four coyotes examined were infected with heartworms. However, during 1994 through 1996, after the drought had ended, prevalences were 91% in 23 adult coyotes and 40% in 10 subadult coyotes. Heartworm intensity did not differ by sex of coyote, and averaged (+/- SE) 19.4 +/- 3.8 among adults; one subadult had > 238 heartworms. The prevalence and intensity of heartworm infection in coyotes reported here for 1994 through 1996 are the highest reported anywhere in the United States.

Trypanosoma cruzi frequently infects wild mammals in the southern United States but little is known about the effect of the parasite on reservoir hosts such as the raccoon (Procyon lotor). To investigate this issue, 30 raccoons trapped on St. Catherine's Island (Georgia, USA) during September, 1994 were tested for T. cruzi infection by examination of wet mounts of fresh blood and by culturing blood in liver infusion tryptose medium. Thirteen animals (43%) were found to be infected with T. cruzi. Heart tissues from 10 of the infected raccoons and 4 uninfected raccoons were fixed, sectioned, stained and examined for the presence of parasites and evidence of tissue damage. One T. cruzi pseudocyst was found in cardiac tissue from the left ventricle of a female raccoon. In addition, Sarcocystis sp. sarcocysts and schizonts of Hepatozoon sp. were observed in heart tissue from seven of the T. cruzi-infected raccoons. Mild, multifocal and interstitial inflammation was observed in the heart tissues of all 10 of the infected animals. No evidence of T. cruzi pseudocysts or tissue damage was observed in heart tissue from C3H/HeJ mice infected with culture forms of the parasites isolated from raccoons. Our findings suggest that the T. cruzi parasites isolated from raccoons in Georgia are not pathogenic to this host or C3H/HeJ mice and may be of low virulence.

Samples of heart, tongue, oesophagus and diaphragm muscle from twenty-two naturally infected roe deer (Capreolus capreolus) harvested in central Italy were examined for sarcosporidiasis. The structure of Sarcocystis spp. muscle cysts was examined by light and electron microscopy. Only one type of thin-walled cyst was distinguished by light microscopy. Electron microscopy showed cysts having a thin highly folded primary cyst wall, without fibrillar material, that formed thin hair-like protrusions often having a T-form, especially close to host cell mithocondria. The cysts appeared to belong to a single Sarcocystis sp. so that all the animals had monospecific infections. This cyst was compared with cysts described in other cervid in an attempt to determine if single or multiple species of the genus Sarcocystis occur in the Cervidae. Apparently, a single Sarcocystis sp. with a low specificity for the intermediate host can infect the Cervidae.

An 8-yr-old captive, female common wombat (Vombatus ursinus) from Victoria, Australia was euthanased after an illness of 36 days manifested by lethargy, inappetance and terminal coma with respiratory failure. Toxoplasmosis was diagnosed during life by the Toxoplasma direct agglutination test (DAT) which showed a positive initial titre of 1:1,024 at 22 days after onset of illness and a four fold rise in titre to 1:4,098 2 wk later, just prior to death. The Toxoplasma modified agglutination test (MAT) remained negative over this time period. The serological diagnosis was confirmed by histological diagnosis of granulomatous encephalitis, focal myocarditis, interstitial pneumonia and severe adrenal cortical necrosis and the presence of tachyzoites of Toxoplasma gondii in large numbers within the focal necrotic lesions in the brain, myocardium and adrenal cortices. The serological response in the wombat differed from that of the typical eutherian which exhibits a reaction in both the DAT and MAT within 2 wk of infection with T. gondii. An incidental finding was calcification in the media of the ascending aorta and proximal parts of the major arteries.

Four 4-mo-old elk calves (Cervus elaphus) obtained from northeastern Oregon (USA) each were inoculated orally with 250,000 sporocysts of Sarcocystis spp., including S. sybillensis and S. wapiti. Three similar elk calves of comparable ages and weights served as uninoculated controls maintained with the inoculated elk during the experimental period between September and December 1993. Body weights were evaluated at 0 and 90 days postinoculation (PI); packed cell volumes of whole blood were evaluated at 0, 30, and 60 days PI, and numbers of sarcocysts in histologic sections from 11 selected tissues were evaluated at 90 days PI. Significant differences in blood packed cell volumes were not detected between groups (P > 0.05). Except for weight gain, elk remained healthy. Mean (+/- SE) weight gain of inoculated elk (27.1 +/- 1.6 kg) was significantly (P < 0.05) less than that of controls (40.2 +/- 4.9 kg). Mean (+/- SE) number of sarcocysts in tissues of inoculated (114.4 +/- 25.7 cm2) and controls (4.5 +/- 1.4 cm2) differed significantly (P < 0.05). Heart, esophagus and skeletal muscle contained the most sarcocysts. No sarcocysts were detected in brain, spinal cord, or testicles. Histologically, mononuclear myositis and myocarditis, with numerous intralesional sarcocysts were seen. Less severe, but widespread inflammation occurred in brain, spinal cord, and optic nerve. Mortality and anemia were not seen, but weight gain depression was detected in the inoculated elk over the 90 day experimental period.

Nodular lesions containing Hepatozoon sp. schizonts or merozoite-gametocytes were found in the tissues of 67 (96%) of 70 wild-caught martens (Martes melampus) examined in Gifu, Japan, 1991 and 1992. The heart was the most commonly parasitized organ (96%), followed by the perirenal adipose tissue (36%); the diaphragm, mesentery, tongue, omentum and perisplenic adipose tissue generally had a prevalence of 10 to 15%. In the heart, two types of nodular lesions were differentiated based on developmental stages: nodules containing schizonts and nodules consisting of an accumulation of phagocytes containing merozoites or gamonts. Under electron microscopy, mature schizonts contained membrane-bound merozoites with a single nucleus and small scattered electron-dense cytoplasmic granules in the schizont nodules; the merozoites and gamonts were engulfed in a phagosome-like vacuole of phagocytes with the nucleus compressed to one side due to the parasite in the merozoite-gamont nodule.

We determined the prevalence of Dirofilaria immitis (Nematoda, Filariidae) among 433 red foxes (Vulpes vulpes) in northeastern Spain, between 1990 and 1992. Forty-six (11%) of 433 foxes were infected; the intensity ranged from 1 to 36 (mean +/- SE; 4.39 +/- 0.92) nematodes per host. The prevalence of D. immitis was higher in foxes inhabiting riparian zones of the study area. This population has a very high juvenile/adult ratio. Heartworm prevalences did not differ among host sex, weight, or fat condition categories.

Sixteen 6-mo-old battery-reared ring-necked pheasants (Phasianus colchicus) were inoculated orally with 10(5) (group A, ME 49 strain, five birds), 10(4) (group B, ME 49 strain, six birds) and 10(4) (group C, GT-1 strain, five birds) Toxoplasma gondii oocysts. The pheasants in groups A and B remained clinically normal. One of the pheasants in group C died 19 days after inoculation (DAI); T. gondii was found in histological sections of brain and heart and encephalitis, myocarditis and enteritis were the main lesions. Toxoplasma gondii was isolated by bioassays from pooled tissues of five of six pheasants in group B killed 36 DAI. Toxoplasma gondii was isolated from the brains, hearts and skeletal muscles of each of the four pheasants inoculated with the GT-1 strain (group C), and from the brains of four, hearts of three and skeletal muscles of four of five pheasants inoculated with the ME 49 strain (group A). All pheasants developed high (1: 1,600-1:25,600) antibody titers to T. gondii in the modified agglutination test (MAT) 36 to 68 DAI. Antibody titers detected with the MAT were higher than those detected in the indirect hemagglutination and latex agglutination tests. Antibodies were not detected in 1:4 dilution of pheasant sera with the Sabin-Feldman dye test.

Sarcocysts were found in the tongue, diaphragm, heart, intestinal tunica muscularis, and skeletal muscle of bobcats (Felis rufus floridanus) collected in Florida (USA). The tongue was found to be the best indicator tissue for sarcocysts (P less than 0.005). Thirty of 60 bobcats screened were found to contain sarcocysts in at least one of the muscle tissues examined. Of the positive bobcats, 28 of 28 tongues contained sarcocysts, while only 10 of 27 (37%), and 8 of 26 (31%) contained sarcocysts in the diaphragm or cardiac muscle, respectively. Although immune suppression has been suggested as a possible reason for formation of sarcocysts in some carnivores, no such correlation was evident in the bobcats. Comparisons of prey species taken by the panther and bobcat, and overlap of geographical range by the two species leave questions as to the source of infection, and the species of Sarcocystis that is infecting both felids.

Sarcocystis sp. (Eimeriina: Sarcocystidae) is described as a heteroxenous coccidian with domestic dogs as an experimental definitive host and wild sheep (Ovis musimon) as natural intermediate hosts. Mature sarcocysts of this Sarcocystis sp. were examined by transmission electron microscopy. Sarcocysts in various muscle tissues were microscopic, had a thin primary cyst wall and septa and measured 81.0 x 30.5 microns. The cysts were located within muscle cells and were limited by a primary cyst wall (PCW). The cyst surface was highly folded forming densely packed projections. Between the PCW projections the surface of the cyst was marked with pit-like invaginations. The ground substance of the cyst formed a layer at the periphery of the cyst, filled the projections and formed septa which divided the cyst into compartments. Sarcocysts contained numerous bradyzoites that were 15.2 x 3 microns and few metrocytes 11.5 x 3.5 microns. Twelve days after ingesting Sarcocystis sp.-infected wild sheep meat, four dogs began passing sporocysts in their feces: two domestic cats did not pass oocysts or sporocysts after ingesting meat from the same animals. Sporocysts measured 14.8 x 9.9 microns.

Wild canid carcasses were obtained during the 1986-1987 and 1987-1988 trapping seasons in Missouri. Hearts and lungs from 293 coyotes (Canis latrans), 85 red foxes (Vulpes vulpes) and 70 gray foxes (Urocyon cinereoargenteus) were examined for Dirofilaria immitis. Age of hosts was determined by radiographic and histologic techniques. Nineteen coyotes (7%) had from 1 to 100 D. immitis and five red foxes (6%) had from 1 to 7 D. immitis, whereas gray foxes had none. This study indicates that heartworm prevalence differs by wild canid species within the same area and during the same time period.

The occurrence of Dirofilaria immitis in gray fox (Urocyon cineroargenteus) was determined by gross examination, blood samples, and filtered tissue sediments in a sampling of 149 gray foxes taken from Alabama and Georgia during the 1977-78 trapping season. Microfilariae were not found in blood samples obtained from 24 of these gray foxes. Three of 82 male foxes (3.7%) and 1 of 67 female foxes (1.5%) were infected with heartworm. D. immitis rate of infection was 1 of 19 (5.3%) and 3 of 130 (2.3%), respectively, in juvenile and adult gray foxes. Single sex infections with D. immitis occurred in 4 of the 6 foxes, with a maximum nematode burden of approximately eight. Two other infected foxes were encountered separate from this study.

Dirofilaria immitis was found in 8 of 225 (3.6%) red foxes (Vulpes vulpes) collected from fur buyers and trappers in Bond, Clinton, DeKalb, Edgar, Ford, Jasper, Moultrie, and Richland counties, Illinois. Infections ranged from 1 to 23 nematodes per fox. The finding of D. immitis in red foxes represents a new host record for the state.

Fifty-five spotted seals, Phoca largha, from the seasonal pack ice of the Bering Sea were examined for helminth parasites. Twelve species of helminths were found: Anophryocephalus ochotensis, Diplogonoporus tetrapterus, Diphyllobothrium cordatum, Phocanema decipiens, Contracaecum osculatum, Dipetalonema spirocauda, Phocitrema fusiforme, Corynosoma semerme, C. strumosum, C. validum, C. villosum, and Bolbosoma sp. Six species are new host records (A. ochotensis, D. tetrapterus, D. cordatum, D. spirocauda, C. validum, and C. villosum).

Adult Dirofilaria immitis were found in the hearts of 43 of 115 coyotes (Canis latrans) trapped within a 50 km radius of the El Dorado County seat. Of mature coyotes, 45% were positive, with worm numbers averaging 9.0 in females and 16.2 in males. D. immitis microfilariae occurred in the peripheral blood and in lung smears. Microfilariae of Dipetalonema reconditum were present in 14 of the coyotes examined (12%). Several coyotes showed enlarged hearts with gross pathological changes.

Schizonts of Hepatozoon sp. were found in the myocardium of an adult cyote (Canis latrans) collected from the Aransas National Wildlife Refuge, Austwell, Texas. This constitutes the first time hepatozoonosis has been recorded in Canidae in the Western Hemisphere.

The prevalence of Sarcocystis sp. (Protozoa: Sarcocystidae) in fallow deer (Cervus dama) in Tuscany, Italy was determined by digestion technique and histological examination. Forty-four of 45 fallow deer were infected. Infections occurred in adult deer and in fawns. Samples from the heart were more intensively parasitized than samples from tongue, oesophagus and diaphragm muscle. With transmission electron microscopy, the primary cyst wall was folded and formed narrow, overlapping, sinuous projections which were often parallel to the cyst surface. Dogs fed heart samples from infected fallow deer shed sporocysts after 10-11 days. Cats fed the same samples did not shed any sporocysts.

Sarcocysts of Sarcocystis odocoileocanis were found in tissue sections of hearts and tongues examined by light microscopy from 30 (88%) of 34 white-tailed deer (Odocoileus virginianus). Hearts were infected less often (13 of 34, 38%) than were tongues (30 of 34, 88%). Sarcocysts of Sarcocystis odoi were not observed in the white-tailed deer examined. A gray fox (Urocyon cinereoargenteus) excreted sporocysts after consuming tongues of white-tailed deer infected with S. odocoileocanis. Two goats inoculated with either 50,000 or 500,000 sporocysts of S. odocoileocanis isolated from the gray fox did not have sarcocysts in tissue sections of the heart, tongue, diaphragm, or esophagus when examined 122 days postinoculation. Dogs fed these tissues from control or inoculated goats did not pass sporocysts in their feces. The present study demonstrates: (1) a high prevalence of S. odocoileocanis infection in white-tailed deer in Alabama, and (2) that goats are not suitable intermediate hosts for S. odocoileocanis.

Ninety-five percent of the larvae of Contracaecum spp. were found in the atrium of the heart of fathead minnows (Pimephales promelas) and five- and nine-spined sticklebacks (Culaea inconstans and Pungitius pungitius). Atria containing nematodes were two to three times larger than an atria from uninfected fish, were thin walled and the muscular trabeculae were damaged. Atria with larvae were congested with blood that appeared to be organizing and extending as a thrombus into the ventricle, but there was no other evidence of a host response. Alternatively, there was an intense cellular response surrounding larvae in the body cavity of these and other host species. Apparently, this parasite which lacks host specificity has evolved an additional strategy to evade the host immune response in sticklebacks and fathead minnows.

The heart and lungs from 32 adult dingoes (Canis familiaris dingo) were examined for canine heartworm (Dirofilaria immitis) infection. Eighteen of 32 (56%) samples were infected, with intensity of infection ranging from 1 to 31 worms per animal. Seven of 18 (39%) infections were single sex infections. Large numbers of circulating microfilariae were present in blood from all dingoes infected with both sexes of worms.

During a histopathologic survey of 240 dasyurid marsupials a high prevalence of infection of Toxoplasma gondii was found in eight of thenine species examined. Amongst the infected species, endemic infection in field animals was proved in Dasyuroides byrnei, but there was also good evidence of laboratory infection probably derived from raw sheep tissues in their diet. Infection was never demonstrated in animals less than six months of age. The 21 Antechinus stuartii examined remained free from infection despited a lengthy stay in the laboratory and a similar diet. This freedom from infection may indicate a particular resistance to Toxoplasma infection by this species.

Heart, esophagus, diaphragm and skeletal muscle obtained from various herbivores on the National Bison Range were examined grossly for Sarcocystis. Sarcocystis was found in 81, 50, 50, and 13% of the mule deer, (Odocoileus hemionus), white-tailed deer (O. virginianus), elk (Cervus elaphus), and bison (Bison bison), respectively.

A single juvenile male raccoon (Procyon lotor) was found naturally infected with Dirofilaria immitis. Two immature female worms were found in the heart of this raccoon at necropsy. Lesions attributable to the presence of these parasites were not found. Histopathologic examination of various tissues did not reveal any microfilariae. The raccoon may serve as an aberrant definitive host for this parasite, however, patent infections have not been reported.