A review of surveillance data on animal rabies from the Centers for Disease Control revealed 104 cases of rabies in rodents and lagomorphs for 1971 through 1984 in the United States; 80% of these were reported between 1980 and 1984. Woodchucks (Marmota monax) accounted for 64% of the cases. Most of the cases of rabies in woodchucks were associated with an epizootic of rabies in raccoons (Procyon lotor) in the mid-Atlantic states. In rabies endemic areas, humans exposed to woodchucks should receive rabies postexposure prophylaxis if the animal is not available for testing. The decision to administer postexposure prophylaxis to humans exposed to other rodents and lagomorphs should take into consideration the epidemiology of rabies in the exposing species.

A non-oncogenic retrovirus was isolated from an explanted skin biopsy from a captive California sea lion (Zalophus californianus) with a history of recurring skin lesions. The morphology of the viral particles in electron photomicrographs was characteristic of a foamy virus, a retrovirus in the subfamily Spumavirinae. Viral cytopathic effects consistent with foamy virus infection were observed in subsequent explants of skin and lymph nodes and co-cultivated peripheral blood leukocytes. The sea lion with the persistent foamy virus infection later died from pericarditis caused by Pasteurella multocida. A herpesvirus was isolated from explants of lung.

Sera from 155 Pacific walruses (Odobenus rosmarus divergens Illiger), sampled in the Chukchi Sea during the summer of 1983, were tested for serum neutralizing (SN) antibodies to six marine calicivirus serotypes. Serotypes tested included San Miguel sea lion virus (SMSV) types 1, 5, 8, and 10, previously isolated from northern fur seals (Callorhinus ursinus Linné) in the Bering Sea; walrus calicivirus (WCV), previously isolated from walrus feces collected off sea ice in the Chukchi Sea; and Tillamook calicivirus (TCV), a bovine isolate from Oregon of suspected marine origin. No antibodies were found to SMSV-1, SMSV-10, or TCV. Antibodies to SMSV-5 were found in two animals (titers 1:20 and 1:160); antibodies to SMSV-8 were found in four animals (all 1:20); and antibodies to WCV were found in one animal (titer 1:40). Antibodies to WCV have been found in the Pacific walrus previously; however, this represents the first report of antibodies to any of the SMSV serotypes in this marine mammal.

Blood collected 314 and 496 days after experimentally infecting splenectomized and spleen-intact American bison (Bison bison) with Anaplasma marginale was infective for splenectomized bovine steers. The pathogenesis was identical to that seen in bovine studies using bovine blood inoculations. A splenectomized bison remained normal clinically, hematologically and serologically for 10 mo after repeated inoculation of ovine blood infected with A. ovis.

Edwardsiella ictaluri isolates collected over the past 7 yr from outbreaks of disease in fish occurring in different geographic areas were screened against 37 antimicrobial agents. Edwardsiella ictaluri were found to be susceptible to most agents active against gram negative bacteria such as aminoglycosides, cephalosporins, the “newer” penicillins, quinolones, tetracyclines, chloramphenicol, nitrofurantoin, and potentiated sulfonamides. Resistance was observed against colistin, sulfonamides, and several agents regarded as effective for gram positive bacteria. There was no evidence of unusual antimicrobial resistance associated with E. ictaluri or of developing resistance.

Ticks were screened for spirochetes and serum samples from white-tailed deer (Odocoileus virginianus) were assayed for antibodies to Borrelia burgdorferi during 1983–1984. Using fluorescein isothiocyanate-labeled rabbit antibodies produced to B. burgdorferi, the etiologic agent of Lyme disease, spirochetes were detected in Ixodes dammini (10.5% of 1,193) and Dermacentor albipictus (0.6% of 157) adults from Connecticut, I. dammini nymphs (49.1% of 108) and adults (64.7% of 99) from Armonk, New York, and in I. scapularis (0.4% of 531) and Amblyomma americanum (3.5% of 173) adults from North Carolina. Infected ticks were either seeking hosts or feeding on deer during the summer and fall. Direct fluorescent antibody staining also revealed spirochetes in two larvae of I. scapularis that emerged from eggs deposited by separate females in the laboratory. Using indirect immunofluorescence tests, antibodies to B. burgdorferi were identified in white-tailed deer living in tick-infested areas of all three states. Aside from minor cross-reactivity, there was no serologic evidence of Treponema or Leptospira infections. Ixodes dammini is a primary vector of B. burgdorferi in northeastern United States, but in North Carolina, other ixodid ticks may transmit this spirochete to humans and wildlife.

A serologic survey of blue wildebeest (Connochaetes taurinus Burchell) and African buffalo (Syncerus caffer Sparrman) in the Masai Mara area was conducted. Antibodies to Brucella spp. were found in 18% of the blue wildebeest and 30% of the African buffalo examined. There were titers in all age groups and in both sexes. Hygromata were seen in both species. The increase in numbers of blue wildebeest and African buffalo which share grazing and watering areas with cattle of the Masai people, makes the presence of infections by Brucella spp. in wildlife an important consideration in any program for control of brucellosis.

The prevalence of Sarcocystis (Protozoa: Sarcocystidae) in white-tailed deer (Odocoileus virginianus) from northeastern Minnesota was determined by histologic examination of tongue samples. Seventy-nine of 100 deer were infected; infection was higher in yearlings and adults than in fawns. Sporocysts of Sarcocystis were found in 3% of 72 wolf (Canis lupus) scats. Three of four captive wolves fed muscle from a white-tailed deer naturally infected with Sarcocystis shed sporocysts 12–14 days later.

The occurrence of third-stage larvae of the arterial worm (Elaeophora schneideri) in populations of the horse fly, Tabanus lineola hinellus, was studied on South Island, Georgetown County, South Carolina. Over the period from mid-April to mid-October 1982, horse flies had a bimodal pattern of abundance with peak populations in June and September. During individual bimonthly horse fly collections, the prevalence of infection of T. l. hinellus ranged from 0 to 1.23%. Prevalence of infected horse flies was biphasic with peaks in mid-May (1.23%) and mid-August (1.22%), 2 to 4 wk prior to peaks in horse fly populations. The intensity of infection of T. l. hinellus increased as time progressed and was highest in late summer. This increase resulted in greater recovery of infective larvae during August–September (mean intensity = 25) than in May–June (mean intensity = 4). Both prevalence and intensity of infection of T. l. hinellus were low compared to primary intermediate hosts of E. schneideri in the western U.S.

A study was initiated to ascertain the prevalence, effect and interaction of the adult stages of the parasitic copepod, Lernaeocera branchialis, on Atlantic cod concurrently infected with a hematozoan, Trypanosoma murmanensis, by comparing condition (K) factor, organ somatic indices, hematological values and lipid concentrations of the liver from infected and uninfected fish of comparable length. Prevalence of the copepod varied from 9 to 21% and was highest in fish examined on the southern coast of Newfoundland. Body condition and blood values were significantly lower in young cod infected with two parasites whereas only K-factor was altered in two size classes parasitized by one copepod. Although lipid concentrations were similar in three length groups of fish without and infected with L. branchialis, the pooled values were significantly greater among the infected group. Mortality occurred only in juvenile cod infected with the copepod and T. murmanensis concurrently. Cod which survived dual infections had lower K-factor and blood values than controls or fish harboring single, parasitic infections. It is concluded that an infection with an adult L. branchialis does not impair the health of fish in this area of the northwestern Atlantic Ocean, but the presence of T. murmanensis concurrently can potentiate its effect.

Fry of brook trout, Salvelinus fontinalis (Mitchill), were infected under controlled conditions with Gyrodactylus salmonis (Yin and Sproston, 1948) and the course of infection followed for 22 days in four groups of 40 fish and for 60 days in a group of 200 fish. Between 15 and 44% mortality occurred among infected groups compared with less than 5% in noninfected control groups. Intensely infected moribund fish were cachexic, lethargic, and often darkened in color. Histologic studies revealed that intensely infected fish had a thinner epidermis with fewer goblet cells than control fish. Internally the only obvious lesions involved the kidney where there was extensive tubular degeneration and necrosis. It is hypothesized that attachment and grazing activity by G. salmonis can lead directly to death of fry through disruption of the osmotic permeability of the epidermis. There was no evidence of secondary invasion by bacteria or fungi.

The lesions of naturally occurring elaeophorosis in white-tailed deer (Odocoileus virginianus) were studied. Arterial changes caused by adult Elaeophora schneideri occurred mainly in cephalic arteries and were characterized by circumferential intimal thickening, disruption of the internal elastic lamina, and verminous thrombosis. Microfilariae caused focal necrosis and fibrosis in the myocardium, but produced only minor changes in other tissues. Radiographic studies indicated that E. schneideri can cause impairment of the cephalic arterial circulation in white-tailed deer. Eleven of 14 (78%) infected deer had oral food impactions, with sublingual impactions being most common. Seven deer with impactions had other oral pathologic conditions, such as gingivitis, loose or absent premolar and/or molar teeth, and remodeling and/or lysis of mandibular bone. The evidence indicates a relation between food impactions and infection by E. schneideri in white-tailed deer, but no definitive connection was established.

Pathogenesis of myiasis due to the muscid fly Philornis deceptivus in nestling pearlyeyed thrashers (Margarops fuscatus) in the Luquillo Rain Forest, Puerto Rico was investigated. Philornid larvae penetrated the host integument, underwent a period of development and growth, and established, as third instar larvae, between the dermis and the body musculature. Movement into this location plus growth and development of the fly larva appeared to be linked to the ingestion of host tissues including red blood cells, mononuclear cells which infiltrated from focal accumulations adjacent to the lesion, and necrotic cellular debris which accumulated in the lesion. The resultant increase in size of the larvae greatly displaced the host integument. Following the evacuation of the larvae for the purpose of pupation, repair of the cavernous lesion was initiated with the production of an intense organized fibrinous exudate. Macrophages and plasma cells predominated with vascular congestion in surrounding tissues. Over the 21-day nest period, nestlings were subject to successive infestations of large numbers of larvae and host responses to these appeared to significantly debit an energy budget responsible for nestling development and growth. Nestling mortality and post fledging survivorship appeared linked to the impact of these energy demands.

Necropsy of a 7-yr-resident peregrine falcon (Falco peregrinis) from Baltimore showed a Pseudomonas infection involving the pharynx as the immediate cause of death. Concentrations of lead in liver and kidney measured 0.74 and 1.40 ppm, respectively. A survey of lead exposure was performed on 40 urban rock doves (Columba livia). Thirteen additional rock doves were collected from sites removed from lead contamination and served as controls. The mean concentration of lead in the blood of the urban rock doves was 0.96 ppm (range 0.29–17.0 ppm) compared to 0.05 ppm (0.01–0.07 ppm) for control birds. Ninety-eight percent (39/40) of the urban rock doves had elevated concentrations of lead in their blood, while 27% (11/40) had sublethal concentrations. None of the control birds had increased concentrations of lead in their blood. Concentrations of lead in liver and kidney of 13 urban rock doves were 3.48 ppm and 9.53 ppm, respectively, compared to concentrations of 0.43 ppm and 0.50 ppm for four control rock doves. From these data a mean total concentration of lead per rock dove was calculated at 4.60 ppm for urban birds and 0.33 ppm for control birds.

Fawn viability was tested in captive, pregnant white-tailed deer (Odocoileus virginianus) immobilized with xylazine hydrochloride and ketamine hydrochloride and reversed by yohimbine hydrochloride or tolazoline hydrochloride. Nine pregnant does were immobilized 10 times each from December 1984 to May 1985. Their mean parturition date was 8 June. The number of fawns produced per pregnant doe was 1.88. Mean weight of newborn fawns was 4.18 kg. Seventy-five percent of the does produced twins or triplets. Three (20%) fawns died postnatally within 48 hr, but the remaining 12 survived for the full 72 hr they were allowed to remain with their dams. These observations compare favorably with those of non-immobilized captive deer on similar diets.