Raccoons (Procyon lotor) were infected by the nasal/oral route with as little as 10² plaque forming units (PFU) of pseudorabies virus (PrV). There was no apparent difference in the susceptibility of raccoons to infection with either of two virulent field strains or with the naturally avirulent K strain which has been used in modified live virus vaccines. Each of these three viruses was transmitted by contact to uninfected raccoons. All raccoons that were infected with virulent field strains died; however only two of 1118%) raccoons that were infected with the K strain died. One of four raccoons that survived infection with the K strain survived superinfection with virulent virus. This finding was significant because it could be a mechanism by which virulent PrV can be introduced and persist in the raccoon population. The possibility of this event occurring is increasing because of the widespread prevalence of PrV and the use of modified live virus vaccines for controlling clinical pseudorabies in swine. Virus neutralizing activity was found in five of 47 serums collected from raccoons that were trapped in PrV endemic areas. This observation implies that a herpesvirus, possibly PrV, may be present in the wild raccoon population.

Prevalence and conditions for occurrence of Clostridium botulinum type C were examined on phosphate-mine settling ponds and a natural wetland in northern Florida between April 1981 and March 1982. Substrate samples were collected monthly (winter) and semi-monthly (summer) from 16 locations on seven ponds. Selected environmental parameters were measured at each location at the time of sampling. Mouse inoculation tests and toxin neutralization tests using enrichment culture filtrates were conducted to identify C. botulinum type C in the samples. The bacteria were identified in 26 (5.6%) of 467 sediment samples. Occurrences were distributed over four of the seven ponds and included nine of the 16 sample locations, but were restricted to the months April through October. The organism occurred over a wide range of ecological conditions found on the ponds during these months. If the presence of C. botulinum type C in the substrate is a prerequisite for botulism to occur, the prevalence and fairly wide distribution of this organism on settling ponds makes it difficult to predict where future outbreaks may occur.

A bacteriological and serological study of 201 wild capybara from the llanos, State of Apure, Venezuela was made to isolate Brucella from spleen and lymph node tissues and determine the role of this rodent as a reservoir of this bacteria. Twenty-three isolations were made, eight were identified as B. abortus and 15 as B. suis by oxidative metabolic techniques. A Poly B antigen in immunodiffusion in gel test was compared with other serologic tests. There was good correlation and 58% of sera were positive. The age and sex distribution of animals from which isolations were made and serological reactors indicated that this species may be an important alternate host of Brucella spp. in Venezuela.

The serologic types of 265 isolates of Pastenrella multocida collected from 50 species of wild birds and seven species of wild mammals over a 22-yr period were determined with the gel diffusion precipitin test. Antigens prepared from these isolates reacted with reference P. multocida antisera representing serotypes 1, 2, 3, 4, 5, 6, 7, 8, 12, and 15. Antigens from some isolates reacted slightly with antisera from more than one serotype. Overall, gel precipitin reactions involving serotype 1 (65%) and 3 (20%) were the most prevalent.

During the hunting seasons of 1979 and 1980, sera were collected from 713 white-tailed deer in Missouri and tested for antibodies to Brucella abortus using the standard tube agglutination, standard plate agglutination, Brucella buffered antigen card agglutination and rivanol agglutination tests. Only one sample was considered to be positive for Brucella antibodies. This study demonstrated that white-tailed deer in Missouri were not an important reservoir host of brucellosis.

Antibodies to Brucella spp. were detected in sera of seven of 67 (10%) caribou (Rangifer tarandus), one of 39 (3%) moose (Alces alces), and six of 122 (5%) grizzly bears (Ursus arctos). Antibodies to Leptospira spp. were found in sera of one of 61 (2%) caribou, one of 37 (3%) moose, six of 122 (5%) grizzly bears, and one of 28 (4%) black bears (Ursus americanus). Antibodies to contagious ecthyma virus were detected in sera of seven of 17 (41%) Dall sheep (Ovis dalli) and five of 53 (10%) caribou. Antibodies to epizootic hemorrhagic disease virus were found in sera of eight of 17 (47%) Dall sheep and two of 39 (6%) moose. Infectious bovine rhinotracheitis virus antibodies were detected in sera of six of 67 (9%) caribou. Bovine viral diarrhea virus antibodies were found in sera of two of 67 (3%) caribou. Parainfluenza 3 virus antibodies were detected in sera of 14 of 21 (67%) bison (Bison bison). Antibodies to Q fever rickettsia were found in sera of 12 of 15 (80%) Dall sheep. No evidence of prior exposure to bluetongue virus was found in Dall sheep, caribou, moose, or bison sera.

A total of 222 birds, captive or free-flying in the Oklahoma City Zoo, were examined for blood parasites; 31 (14%) harbored Haemoproteus and/or Leucocytozoon. While 21% of the indigenous avifauna were infected, only 8% of the exotic bird species harbored haemoproteids and these parasites were also exotic to North America. There was no evidence to indicate that exotic infections were transmitted to native birds or vice versa.

The objectives of this study were to determine if the raccoon was a useful experimental animal for infections of Trichinella and to determine if the ability of Trichinella to survive freezing conditions, known to occur in wild animals, could be duplicated under laboratory conditions. The isolates of Trichinella used in this study were from pigs, polar bear, wolverine, arctic fox and T. spiralis var. pseudospiralis originally isolated from a raccoon in the USSR. The raccoon was found to be a useful experimental host for Trichinella as it was easily maintained under experimental conditions and was readily infected. Infectivity indices were lower in raccoons than in laboratory mice. Those isolates of Trichinella with the longest association with laboratory mice had the lowest infectivity indices. The isolate of Trichinella from an arctic fox retained its ability to survive freezing temperatures when introduced into raccoons held under experimental conditions. The type of host, method of passing the parasite and perhaps a special genetic characteristic of arctic isolates seem to be important factors influencing their ability to survive freezing temperatures.

Intestinal and lung parasites of 85 mountain hares (Lepus timidus) and 24 European hares (L. europaeus) were examined. The species of parasites found in both hare species were Trichostrongylus retortaeformis Zeder, 1800; Mosgovoyia pectinata Goeze, 1782 and Protostrongylus pulmonalis Froelich, 1802. Eimeria semisculpta Madsen, 1938 and E. townsendi Carvalho, 1943 were found only in the European hares and Eimeria leporis Nieschulz, 1923 and Dicrocoelium dendriticum Rudolphi, 1819 only in the mountain hares. Ninety-five percent of the mountain hares and 88% of the European hares were infected with parasites. Mountain hares were more commonly infected with P. pulmonalis and D. dendriticum while European hares were more commonly infected with Eimeria spp. and T. retortaeformis. Young mountain hares were more often infected with M. pectinata and adult mountain hares with P. pulmonalis. The management technique of winter-feeding did not increase significantly the percentage of infected animals. Dicrocoelium dendriticum was found only in hares from islands where sheep had grazed during the summers. The absence of cysticerci of Taenia pisiformis Bloch, 1780 in this survey may be a reflection of improved hygiene practices instituted by hunters.

Scabies due to infestation by Psoroptes oris was monitored from 1979 through 1981 in Nelson's desert bighorn sheep in northwestern Arizona. Visual examinations for ear lesions and evaluations of ear scrapings were used to assess the prevalence of mites in sheep that were live-captured or killed during the hunting season. The prevalence of psoroptic scabies in live-captured sheep for the years 1979, 1980, and 1981, was 25%, 25% and 0% respectively, and was higher in rams (1979, 65% 1980, 100%) than in ewes (1979, 11% 1980, 0%). The severity of ear lesions was also greater in the males. The prevalence in harvested rams was 23% 44% and 7% respectively, for the years 1979–1981. The severity of the ear lesions was highest in 1980. Lesions were confined to the ears. An aerial census of bighorns in the Black Mountains during May of 1981 showed a 38% decrease in total observations from the previous year and a drop in the ewe lamb ratio from 0.52 in 1980 to 0.29 (P ≤ 0.01) in 1981. In the Lake Mead area, there was a population census decline of 33% in 1981 and a non-significant decline in the ewe lamb ratio from 0.46 to 0.40. The population decline in 1981 and the increased prevalence and severity of psoroptic scabies in the 1980 survey in both areas were believed to be related to the high bighorn population densities in 1980 and the prevailing drought.

In July 1981, investigations on parasites, diseases, and herd health status were conducted on sympatric populations of sika deer (Cervus nippon) and white-tailed deer (Odocoileus virginianus) from Blackwater National Wildlife Refuge (Maryland) and Chincoteague National Wildlife Refuge (Virginia) on the Delmarva Peninsula. Five adult deer of each species were collected from each location and subjected to thorough necropsy examinations and laboratory tests. White-tailed deer at both locations harbored protozoan, helminth, and arthropod parasites typically associated with this species throughout the southeastern United States. In contrast, sika deer at both locations harbored only light burdens of ticks, chiggers, and sarcocysts. Serologic tests for antibodies to seven infectious disease agents revealed evidence of exposure to bovine virus diarrhea (BVD) virus, infectious bovine rhinotracheitis virus, and parainfluenza₃ virus in white-tailed deer, but only BVD virus in sika deer. At both locations the general health status of sika deer was superior to that of white-tailed deer.

Chronic bacterial pneumonia was diagnosed in two free-ranging Eastern box turtles. Mucoid exudation into the upper respiratory tract and bilateral, caseating pneumonia were seen grossly. Microscopically, chronic, active inflammation with pseudomembrane formation occurred in the nasal sinuses and lungs while caseating granuloma-like structures were also observed in alveoli and associated infundibulae. Since viral, protozoal or fungal agents could neither be demonstrated in tissue sections by light or electronmicros-copy, nor could they be isolated in vitro, the gram-negative bacteria, seen in large numbers within the lesions and easily cultured in vitro, were considered the etiologic agents of this disease.

The trematode Metorchis conjunctus (Cobbold, 1860) was found in seven of 211 wolves from Saskatchewan which were examined between 1976 and 1983. The parasite caused cholangiohepatitis with periductular fibrosis in the liver of all the wolves, and chronic inflammation and fibrosis of the pancreas in two animals. The wolves with pancreatic involvement were emaciated. Five of the seven infected wolves were from one local area, and three of these were from a pack known to consume fish.