The prevalence of 7 species of Coccidia is reported from 137 Colorado pikas, Ochotona princeps, collected on Mt. Evans, Clear Creek County, Colorado, during the summers of 1968, 1969, and 1971. Identification of the parasites was based on the structure of the unsporulated oocysts which, at least for those species that have been described to date from North American pika hosts, are highly distinctive for most species. Photographs illustrate the differences in size, shape, and form of the oocysts of the various species. A key to the Coccidia of pikas, based on the descriptions of sporulated oocysts, is presented.

The infectious hematopoietic necrosis virus (OSV strain) and the virus of haemorrhagic septicaemia of rainbow trout (Salmo gairdneri) (Denmark strain) were examined for possible antigenic relationship by plaque neutralization using homologous and heterologous antisera. No neutralization of either virus was observed on exposure to heterologous antiserum. This indicates that there is no antigenic relationship between these two viruses as determined by this method.

Trichomonas gallinae was present in 47% (57/121) of adult, 41% (7/17) of juvenile, and 29% (2/7) of nestling mourning doves (Zenaida macroura) from Lincoln, Nebraska. Throat lesions were present in 5.9% (43/724) of the mourning doves trapped for banding. Two of four pigeons (Columba livia) possessed T. gallinae, but none contained throat lesions.

Serum samples were collected from 29 Rocky Mountain bighorn sheep (Ovis canadensis) in their natural habitats in Colorado and Wyoming. Sera were tested for the presence of antibodies to six viruses. Hemagglutination inhibition tests indicated 18 sheep had antibodies to PI3, with 9 having titers greater than 1:8 and 24 sheep had antibodies to bovine parvovirus 1, with 24 having titers greater than 1:8. Serum neutralization tests showed one sheep had antibodies to the viruses of blue-tongue and bovine viral diarrhea while no animals had titers to infectious bovine rhinotracheitis. Complement fixation tests revealed 13 sheep had antibodies to the group specific CF antigen of the adenoviruses. Only one animal possessed the group specific precipitating antibody.

Emaciation and enteritis of the small intestine were observed in three cottontail rabbits, Sylvilagus floridanus, which had died shortly after their capture from the wild and introduction into outdoor enclosures. These symptoms were associated with very heavy infection of intestinal flukes, Hasstilesia tricolor. Histological sections collected from the intestine of one rabbit revealed extensive villi destruction attributed to the parasite. Attachment of flukes to one another by ventral suckers was also observed. The high prevalence of infection of this parasite in Montgomery County, Virginia, indicates that it may be of local importance as a pathogen causing fatal consequences in its host.

Examination of five coastal species of sea birds on Long Island, New York, revealed 18 cases of subcutaneous emphysema among over 11,000 chicks handled over a 5 year period. The condition may result from a variety of causes, but trauma to young birds from territorial adults is believed to play an important role. The condition is often benign, but when severe may interfere with both cryptic posture and escape. It should be distinguished from generalized edema, a condition which might occur in the same populations. Treatment is simple and usually successful.

The skulls and brains of 19 northern fur seals (Callorhinus ursinus) were studied. These animals had been rendered unconscious by blunt head trauma as part of the harvest procedure on the Pribilof Islands of Alaska. All seals had depressed, comminuted fractures of the skull. Epidural, subdural and subarachnoid hemorrhage were frequently present. In addition, the brains showed varying prevalence and degrees of laceration, superficial contusion and hemorrhage in deep midline or paramedian structures and ventricular system. Lesions observed were related to the head trauma.

A free-living brown hare (Lepus europaeus) was found to have arteriosclerosis of the thoracic segment of the descending aorta. The lesions were well advanced and resembled Mönckeberg's medial sclerosis. The animal was also suffering from a severe purulent metritis.

Hemorrhagic ulcerative stomatitis caused by the biting louse Piagetiella peralis was diagnosed in one live and three dead juvenile white pelicans (Pelecanus erythrorhynchus). The pathology of the condition is described, and the significance of infestation with this parasite is discussed.

Intraerythrocytic organisms were found in a Moroccan tortoise Testudo graeca imported into England. It is suggested that the parasites belong to the Rickettsia group of organisms and that Hyalomma aegyptium is possibly the vector.

Salmonellosis caused by Salmonella typhimurium was one of several factors responsible for losses among young herons being held at the Patuxent Wildlife Research Center. The infection was demonstrated in five black-crowned night herons (Nycticorax nycticorax), three common egrets (Casmerodius albus), two little blue herons (Florida caerulea), one cattle egret (Bubulcus ibis), one snowy egret (Leucophoyx thula) and one Louisiana heron (Hydranassa tricolor). The disease was characterized by emaciation, focal liver necrosis, and frequently by a caseo-necrotic enteritis.

Six of 14 wild white-tailed deer fawns (Odocoileus virginianus) were found infected with a species of Strongyloides, probably S. papillosus. All positive fawns were obtained from northern Florida during March through June 1973, and were 1-3 weeks of age when first examined. Egg counts ranged from <50 to 2,050 eggs per gram of feces. This is the first report of this potentially pathogenic parasite in free-ranging white-tailed deer fawns.

Granulomatous oral masses were observed in two Chinook salmon (Oncorhyncus tschwytscha) smolts with systemic nocardiosis. Gross and histopathological lesions are described indicating the proliferative inflammatory nature of this diesase.

A bottle-nosed dolphin, Tursiops truncatus, delivered a stillborn male fetus, and three months later, died in dystocia. The second fetus, a female, had a transposed pulmonary artery and aorta and an interventricular septal defect.

A ten-year serologic and virologic investigation into the activity of enzootic bluetongue (BT) virus was conducted in southern Texas white-tailed deer (Odocoileus virginianus texanus). Eighty-nine percent of 484 adult deer, 36% of 129 juvenile deer and 93% of 182 neonatal deer were sero-positive of BT. Antibody was not detected in fetal fawns but was found in colostrum samples. Sentinel fawn studies demonstrated that maternal antibody persists at least 8 weeks and that BT was transmitted during the fall months. The virus was isolated from a sentinel fawn but could not be recovered from deer with antibody or with organizing lesions suggestive of previous BT infection. Virus was not isolated from deer ectoparasites.

A single specimen of Hymenolepis diminuta (Rudolphi, 1819) was recovered from a gray squirrel (Sciurus carolinensis) in Indiana. This represents the first confirmed report of this species of tapeworm in the gray squirrel.

This study was conducted to determine the susceptibility of free-ranging black-tailed deer (Odocoileus hemionus columbianus) to tansy ragwort poisoning. The results showed that captive black-tailed deer would not consume tansy ragwort unless they were unable to acquire adequate intake from other food sources. Since some experimental deer consumed an average of 24% of their body weight as dry matter from tansy ragwort over a 42-day period without any symptoms of toxicity, it appears that deer may be relatively tolerant to poisoning by this plant. It seems unlikely that tansy ragwort would cause toxicity problems with free-ranging black-tailed deer.