Waterfowl botulism is unique among intoxications because toxin produced within its victims leads to secondary poisoning of other birds. Because of this phenomenon, the epizootiology of the carcass-maggot cycle of botulism resembles that of an infectious disease and the reproductive rate (R) of the disease could be defined as the average number of secondary intoxications attributable to a single carcass introduced into a marsh. I propose that toxin production and botulism occur commonly at a low level in many marshes and that factors which influence R determine when the disease expands into a large epizootic. A model that incorporates the number of carcasses occurring in a marsh, the probability of a carcass containing spores, the probability of a carcass persisting until toxin-bearing maggots emerge, and the contact rate between live birds and toxin, may be useful for predicting the extent of secondary-poisoning, for identifying questions for research, and as a theoretical basis for management.

As part of an effort to understand extensive, white phosphorus (P₄)-induced waterfowl mortality at Eagle River Flats, Fort Richardson, Alaska (USA), we conducted a number of acute toxicity tests using penned mallards (Anas platyrhynchos) in 1993 and 1994. The 24-hr median lethal dose (LD₅₀) for P₄ dissolved in oil was 6.46 mg/kg in adult males and 6.96 mg/kg in adult females. Although the median lethal doses were not statistically different, the female dose-response curve had a statistically shallower slope than that of males. The LD₅₀ for the ecologically more relevant pelletized form of P₄ in adult males was 4.05 mg/kg. In mallards, one mechanism of P₄ toxicity caused rapid (3 to 10 hr) mortality and had signs consistent with anoxia. A second, slower acting mechanism resulted in hepatic and renal pathology including extensive fat deposition in the liver and cellular necrosis. White phosphorus accumulated in adipose tissues, but only for a few days.

We used a combination of Telazol^® (3.3 mg/kg) and xylazine hydrochloride (1.6 mg/kg) to immobilize 144 wild pigs (Sus scrofa) with blow darts. This drug combination was safe and effective for rapidly immobilizing animals ranging in size from 34 to >170 kg and avoided difficulties associated with hand injections. For 123 single injection immobilizations, mean (±SD) induction times and effective handling periods averaged 5 (±2.5) and 52 (±18) min, respectively, and animals generally recovered for release within 120 min of initial injections. Animals that required two injections to immobilize (n = 21) received lower initial doses of Telazol^® and xylazine hydrochloride than those immobilized with a single injection because of errors in estimating body sizes; we found that there was a threshold dose required to immobilize wild pigs from 2.8 to 3.3 mg/kg Telazol^® and 1.4 to 1.6 mg/kg xylazine. Although neither age or sex influenced immobilization parameters, animals in good condition required longer to recover than those in poor condition. However, animals immobilized with two injections recovered as rapidly as those immobilized with a single injection. Heart rates and body temperatures declined slightly during the immobilization period, but respiration rates and blood oxygen saturation levels remained stable. In general, single injection immobilizations were preferable because they minimized problems associated with injecting partially immobilized animals. Because it was difficult to accurately estimate the sizes of large wild pigs (≥90 kg), and because wild pigs that were partially immobilized were difficult to handle, we recommend increasing the drug doses to 4 mg/kg Telazol^® and 2 mg/kg xylazine hydrochloride when injecting relatively large animals to assure single injection immobilizations. Although recovery periods may be prolonged, higher doses of Telazol^® and xylazine should be safe based on data from domestic pigs.

California sea lion pups, Zalophus californianus, (n = 115), were captured and anesthetized for (mean ± SD) 17.6 ± 7.8 min on San Miguel Island, California (USA) in November of 1992. Mask isoflurane anesthesia allowed intubation in 7.1 ± 2.74 min. Pups recovered and walked in 7.32 ± 4.8 min. Mask anesthesia in pups resulted in relaxation in 45 ± 14 sec. Safe, brief anesthesia was delivered in support of weighing, medical evaluation, and short surgical procedures. Recovery character of all pups was sufficient to permit release to the free ranging state immediately after surgery, saving labor, supervision personnel, and postoperative time.

The skeleton of a wild coyote (Canis latrans), collected in Alturas, California (USA), in 1940 and reported to have died of a blowfly infection, was analyzed. The axial components, primarily a series of fused and deformed vertebrae, had classic osteological indications of spondylosis deformans, a trauma-induced disorder. Severe crippling due to a crushing-type strain was identified as the primary pathological condition to which the coyote succumbed, with death hastened by vertebral degeneration and the complicating infection.

Eleven cases of congenital anomalies were identified in 210 (5%) juvenile northern elephant seals (Mirounga angustirostris) found stranded along the central California (USA) coast from 1 January 1988 to 31 December 1995. Seven individuals had mild-to-moderate hydrocephalus involving the lateral ventricles bilaterally, or the lateral and third ventricles. Two animals had severe cardiac anomalies: hypoplasia of the right ventricle with overriding aorta, and ventricular septal defect. Other anomalies included single cases of hydronephrosis, focal pulmonary dysplasia, and congenital epidermal angiomatosis. Common intercurrent disease processes were verminous pneumonia and arteritis, verminous enteritis and colitis, and splenic and hepatic hemosiderosis. The more severe anomalies were considered to be the cause of debilitation and stranding. Milder anomalies were found incidentally during routine gross necropsy and histopathologic examination.

We observed a total of 102 striped skunks (Mephitis mephitis) from March to July of both 1991 and 1992 in Stutsman County, North Dakota (USA) during an experiment with food supplementation. Twenty-three apparently healthy skunks in 1991 and 56 in 1992 were equipped with radio-collars. In 1991, one of the 23 was tested and found to be rabid. In 1992, 50 of 56 were tested; 35 (70%) were rabid. Of skunks with ages estimated, 19 (66%) of 29 were first year animals in 1991 compared with nine (22%) of 41 first year animals in 1992. All 18 females captured in 1991 were pregnant or parous compared with 21 (60%) of 35 in 1992. The estimated survival rate of skunks was 0.85 during April to June 1991, but only 0.17 during April to July 1992. In 1992, the survival rate of first year skunks was 0.08, compared with 0.35 for older animals. Eleven (31%) of 36 skunks found dead of rabies or in late clinical stage were located below ground. We detected no differences in 1992 between healthy and rabid skunks in estimated mean (±SE) rate of travel (232 ± 14 m/hr), distance traveled (2,047 ± 141 m/night), or home range size (1.6 ± 0.4 km²) during half-month periods from April through June. Among rabid skunks, mean rate of travel tended to decrease from 298 ± 48 m/hr during the 14 days preceding the clinical period of rabies (pre-clinical) to 174 ± 48 m/hr during the clinical period of rabies (14 days immediately before death). Similar decrease occurred in distance traveled in a night (2,318 ± 281 m, pre-clinical; 1,497 ± 281 m, clinical). Mean home range size of males (2.8 ± 0.4) was greater than of females (1.2 ± 0.4) during the pre-clinical period, but during the clinical period home range sizes of males (1.8 ± 0.4) and females (1.8 ± 0.4) were similar. Mean home range size of females did not differ between pre-clinical (1.2 ± 0.4) and clinical (1.8 ± 0.4) periods (P = 0.22). Deaths of skunks from rabies in 1992 tended to be more spatially clumped than expected had they been random, mostly due to deaths detected before 8 May. We detected no correlation between locations of animals found dead of rabies and dates of death.

We describe a rabies epizootic in northwest Alaska (USA) during 1989 and 1990 which resulted in mortality to several different wolf (Canis lupus) packs. Four radio-collared wolves were confirmed to have rabies while evidence for seven others was strongly suggestive but not confirmed. The wolf population declined during the rabies epizootic; thus rabies may have been a significant limiting factor.

The role of white-tailed deer (Odocoileus virginianus) in the epidemiology of Ehrlichia chaffeensis and the agent of human granulocytic ehrlichiosis (HGE) is not fully understood, and diagnostic procedures may be complicated by the recent detection of 16S rDNA sequence from an Ehrlichia sp.-like organism in wild deer. A specific forward primer (DGA) and an Ehrlichia spp. reverse primer (GA1UR) were constructed to amplify this new, distinct Ehrlichia sp.-like 16S rDNA. The DGA primer, a forward primer specific for E. chaffeensis (DCH), and a forward primer specific for the E. phagocytophila genogroup (GE9f) were each used with GA1UR in nested polymerase chain reactions to amplify 16S rDNA sequences from control samples containing the deer Ehrlichia sp.-like organism, E. chaffeensis, or the HGE agent. Primer pairs DGA/GA1UR and DCH/GA1UR specifically amplified 16S rDNA sequences from the corresponding target organism, whereas GE9f/GA1UR amplified 16S rDNA sequence from both the HGE agent and the deer Ehrlichia sp.-like organism. With a nested PCR using DGA/GA1UR and DCH/GA1UR on DNA extracted from white blood cells from 62 deer from 10 populations in four U.S. states, we observed a high prevalence (65%) of 16S rDNA sequences of the deer Ehrlichia sp.-like organism, and a low prevalence (5%) of the E. chaffeensis sequence. In this field survey, E. chaffeensis-reactive antibodies detected by indirect fluorescence assays were associated (P < 0.001) with PCR evidence of the deer Ehrlichia sp.-like organism, but not E. chaffeensis. Infestations of Amblyomma americanum also were associated (P < 0.001) with PCR evidence of the deer Ehrlichia sp.-like organism. The potential for serologic cross-reactions and non-specific PCR products arising from the deer Ehrlichia sp.-like organism should be considered when evaluating the role of deer and their ticks in the epidemiology of ehrlichial pathogens of humans.

In New Zealand, the biological control of introduced bnishtail possums (Trichosurus vulpecula) may be the only affordable option for achieving a significant long term reduction in pest numbers on a national scale. Leptospira interrogans serovar balcanica is among the potential biocontrol agents and vectors currendy being investigated for this purpose. As the transmission pathways of L. interrogans serovar balcanica between possums are poorly understood, the objective of the study was to determine whether infection could result from exposure to contaminated environments. Sixteen individually housed, uninfected possums, in three groups, were regularly exposed over a period of 32 days to contaminated cages or grass enclosures of 16 other experimentally infected possums all shedding leptospires in their urine. None of the 16 challenged possums developed serological evidence of L. interrogans serovar balcanica infection. These results suggest that this organism is unlikely to be transmitted environmentally, supporting previous circumstantial evidence that social contact may be required for transmission of L. interrogans serovar balcanica between possums.

Plasma samples collected in 1990 from free-ranging desert tortoises (Gopherus agassizii) with and without clinical signs of upper respiratory tract disease (URTD) from Las Vegas Valley, Clark County, Nevada (USA), were tested by enzyme-linked immunosorbent assay (ELISA) for antibodies to Mycoplasma agassizii, a causative agent of URTD. The relationship between clinical signs and ELISA test results was evaluated. Of the 144 tortoises tested, 45 (31%) had clinical signs while 72 (50%) were seropositive. Presence of clinical signs of URTD was positively related to positive ELISA results (P < 0.0001) regardless of sex or age of the animal. Eighty-four percent of animals with clinical signs tested seropositive. Mucous nasal discharge, the most severe and obvious of the clinical signs, was highly predictive for exposure to M. agassizii based on the ELISA. Ninety-three percent of tortoises with mucous nasal discharge tested seropositive. Serologic testing for M. agassizii antibodies supported clinical signs as useful indicators of URTD, but it also detected potential subclinical infection in 34 (34%) of 99 animals without clinical signs.

Blood samples were collected from 892 grizzly bears (Ursus arctos) in Alaska (USA) from 1973 to 1987. Sera were tested for evidence of exposure to Toxoplasma gondii by means of the modified agglutination test. Two hundred twenty sera (25%) had titers ≥25, the minimum threshold titer. Six hundred seventy-two sera (75%) had titers <25. Antibody prevalence ranged from 9% (18 positive of 196 tested) in southern areas to 37% (162 of 433 tested) in northern areas. There was no readily apparent explanation for these discrepancies in location-specific prevalence.

Blood was collected from 49 adult woodland caribou (Rangifer tarandus caribou) captured in northern Alberta, Canada, from October to February, 1991 to 1992 and 1992 to 1993. Smears of the buffy coat layer and of whole blood were examined microscopically for Trypanosoma sp., and blood was cultured for latent parasites. Trypanosomes were present in 41 (84%) of 49 cultures 9 days or older, but none was detected in fresh blood. Trypanosomes were pleomorphic, consisting of small oval amastigotes, 2 to 8 μm, intermediate-size epimastigotes, 20 to 30 μm in total length (including the flagellum), and large trypomastigotes, 60 to 90 μm length, with pointed ends, a well developed kinetoplast, a long free flagellum, and a prominent undulating membrane. Dividing epimastigotes appeared in pairs or rosettes of five or more organisms. Based on culture characteristics and morphologic features, the organism was identified as Trypanosoma (Megatrypanum) sp.

Metazoan parasites of 50 sika deer (Cervus nippon yezoensis) collected in March 1991 in the Ashoro District in east Hokkaido, Japan, were evaluated. Ten species of helminths and three species of ectoparasites were obtained. Estimated abundance of males of two species of abomasal nematodes, Spiculopteragia houdemeri and Rinadia andreevae, were positively correlated with each other, and were overdispersed; S. houdemeri followed Poisson's and R. andreevae followed a negative binomial distribution. No significant relationship was detected between the estimated abundance of males of these two nematode species and nutritional condition of the hosts. Using a general linear model, the fourth-root transformed estimated abundance of male S. houdemeri was influenced by the main effects of host sex and age. This phenomenon was attributable to the ecological and behavioral features of the deer. The low diversity of the abomasal nematode community was regarded as the result of the extinction of some species of nematodes on Hokkaido Island.

We examined lung parasites of three species of soricids, Sorex cinereus (n = 58), Sorex fumeus (n = 23) and Blarina brevicauda (n = 45) collected from Pennsylvania (USA), from 1990 to 1995. Yeast-like cells of Histoplasma capsulatum var. capsulatum were found in lung sections stained with Grocott s modification of Gomori s methenamine silver, periodic acid-Schiff, Giemsa, and hematoxylin-eosin in two (3%) S. cinereus, eight (35%) S. fumeus and two (4%) B. brevicauda. The number of spores of H. capsulatum in the lungs was low and no inflammatory reaction was evident. The infection was not disseminated to other organs. This is the first report of H. capsulatum infection in any species of shrews of the genus Sorex and the prevalence in S. fumeus was remarkably high compared to those reported for other wild mammals. A nematode, possibly Angiostrongylus michiganensis, was found in the lungs of one S. fumeus on necropsy and in a stained lung section of one S. cinereus. In both cases the host was also infected with the fungus. Pneumocystis carinii, which is the most common lung parasite in Sorex araneus (the numerically dominant Eurasian species of shrew), was not found in any of the North American species of shrew examined in this study.

From December 1991 through January 1995, a disease survey was conducted on herds of free-ranging, hunter-killed elk (Cervus elaphus nelsoni) from three areas in proximity to Yellowstone National Park (YNP), Wyoming (USA), after tuberculosis caused by Mycobacterium bovis was discovered in a captive herd of elk in the area. Complete or partial sets of specimens from 289 elk collected between December 1991 and January 1993 were examined histologically: no mycobacterial lesions were observed. Lesions of tuberculosis were not detected in tonsils or lymph nodes of the head from an additional 99 hunter-killed, adult elk from one area (area 2) collected in January 1995. Neither M. bovis nor M. paratuberctdosis were isolated from any of the specimens cultured. Antibodies to Brucella abortus were detected in serum samples from 0%, 1%, and 1% of elk from three areas sampled (areas 1, 2, and 3), respectively. Brucella abortus biovar 1 was isolated from multiple tissues from one seropositive animal from area 3. Larvae with morphology consistent with Dictyocaulus sp. were found in 12%, 14%, and 0% of fecal specimens tested from areas 1, 2, and 3, respectively. Pasteurella multocida and Actinomyces pyogenes were isolated from a lung with purulent bronchopneumonia and abscesses.

A 12-year-old female bald eagle (Haliaeetus leucocephalus) was found in May 1993 on Santa Catalina Island, California (USA), in a debilitated condition, exhibiting ataxia and tremors; it died within hours. On necropsy, the bird was emaciated but had no evidence of disease or physical injury. Chemical analyses were negative for organophosphorus pesticides and lead poisoning. High concentrations of DDE (wet weight basis) were found in the brain (212 ppm), liver (838 ppm), and serum (53 ppm). Mobilization of DDE, from depleted fat deposits, probably resulted in the lethal concentration in the eagle's brain.

Blood samples were collected from six captive bears and nine free-ranging Marsican brown bears (Ursus arctos marsicanus) in the Abruzzo National Park, Italy, between 1991 and 1995. Sera were tested for evidence of exposure to canine distemper virus (CDV), canine adenovirus type 2, canine coronavirus, and canine parvovirus type 2 (CPV-2). Serologic evidence of CDV and CPV-2 exposure was found in both captive and free-ranging bears. This may be the first report of CDV exposure in free-ranging bears.

From November 1991 through March 1992, we evaluated 101 free-ranging American bison (Bison bison) from Yellowstone National Park, Wyoming (USA) for exposure to infectious organisms that commonly infect cattle. No titers were detected for bluetongue virus, bovine leukemia virus, or Campylobacter fetus in these 101 bison. Detectable antibodies occurred against Anaplasma marginale (eight of 76, 11%), bovine respiratory syncytial virus (31 of 101, 31%), bovine viral diarrhea (31 of 101, 31%), bovine herpesvirus 1 (29 of 76, 38%), Leptospira interrogans icterohaemorrhagiae (four of 101, 4%), L. interrogans hardjo (seven of 101, 7%), L. interrogans autumnalis (one of 101, 1%), L. interrogans bratislava (seven of 101, 7%), L. interrogans australis (one of 101, 1%), and parainfluenza 3 virus (27 of 75, 36%). The low antibody titers and the lack of gross lesions are evidence that while previous exposure to infectious organisms may have occurred, none appeared to have active infections.

An epizootic of eastern equine encephalitis (EEE) at the Patuxent Wildlife Research Center (PWRC), Laurel, Maryland (USA), in 1989 provided an opportunity to determine if EEE immunization protected whooping cranes (Grus americana). Based on seroconversion of 31% of sympatric hatch-year sandhill cranes, Grus canadensis, and a previous 35% case fatality rate in whooping cranes, 17 (37%) of the 46 susceptible whooping cranes should have been exposed to virus and six should have died. As there were no deaths in these birds, the EEE vaccination program appeared to be efficacious in this whooping crane population.

Puma lentivirus (PLV) antibodies were detected in 13 (25%) of 52 serum samples obtained from cougars (Felis concolor) collected by hunters. The serum samples were collected from November 1993 through January 1994 from four specific regions throughout the state of Washington (USA), and included the Olympic Mountains, the Cascade Mountains, the Blue Mountains, and the Selkirk Mountains. More (38%) seropositive cougar samples originated from the Cascade Mountains than from any other site. The overall seroprevalence for PLV infection in Washington cougars was higher than previously reported for cougars sampled in Oregon and Idaho (USA), but lower than in cougars sampled in Arizona, Colorado, and California (USA).

A 9-mo-old female wolf (Canis lupus) in the Superior National Forest of Minnesota (USA) died from a canine parvovirus (CPV) infection. This is the first direct evidence that this infection effects free-ranging wild wolves.

Avian pox was diagnosed in two eastern screech owls (Otus asio) and two barred owls (Strix varia) living in different regions of Florida (USA) between November 1994 and October 1995. Avian poxvirus infection was confirmed by the presence of eosinophilic intracytoplasmic epidermal inclusions (Bollinger bodies) on light microscopy of tissue from all four owls. Additionally, typical poxvirus particles were demonstrated by electron microscopy of a lesion from one of the eastern screech owls. These are the first published case reports of avian pox in eastern screech owls and barred owls.

In south-central Saskatchewan, Canada, in 1986, 1987 and 1989, the aerobic bacterial flora was evaluated from 75 unhatched raptor eggs of three species: 42 of the Swainson's hawk (Buteo swainsoni), 21 of the ferruginous hawk (Buteo regalis), and 12 of the great horned owl (Bubo virginianus). In addled Swainson's hawk eggs, the most common bacterial genera were Enterobacter (18 eggs), Escherichia (12), and Streptococcus (10). Seven great horned owl eggs and six ferruginous hawk eggs also contained Escherichia coli. Salmonella spp. were not isolated. These bacteria were interpreted as secondary contaminants and not the primary cause of reproductive failure.

Pharyngeal swabs were collected from 298 lesser snow geese (Chen caerulescens caerulescens) at Banks Island (Northwest Territories, Canada) in the summer of 1994. Pasteurella multocida serotype 1 was isolated from an adult male bird and P. multocida serotype 3 was isolated from an adult female goose. Pathogenicity of the serotype 1 isolate was confirmed by inoculation in Pekin ducks (Anas platyrhynchos). The serotype 3 isolate was non-pathogenic in Pekin ducks. This is the first documented isolation of pathogenic P. multocida serotype 1 from apparently healthy wild snow geese.

Bilateral conjunctivitis and episcleritis were identified in an adult European starling (Sturnus vulgaris). A novel mycoplasma species, Mycoplasma sturni, was isolated in pure culture from the conjunctiva of both eyes. The clinical presentation was similar to that of conjunctivitis in house finches (Carpodacus mexicanus) caused by Mycoplasma gallisepticum. However, the histologic lesions were distinct, by the presence of ulceration and epithelial hyperplasia and lacking a lymphoplasmacytic infiltration. Mycoplasma sturni ferments glucose, does not hemadsorb or hemagglutinate chicken erythrocytes, and grows rapidly at 37 C in comparison to other Mycoplasma spp. The role of M. sturni in conjunctivitis in other passerine species is presently unknown.

Hair samples were collected from wild boars (Sus scrofa) in Italy to determine the presence of keratinophilic fungi. Eleven (5%) of 211 boars had fungi: two (1%) had Trichophyton mentagrophytes, five (2%) had T. terrestre, two (1%) had Chrysosporium keratinophilum, one (0.5%) had Chrysosporium tropicum, and one (0.5%) had both C. keratinophilum and T. terrestre. These are the first recorded isolations of C. keratinophilum, C. tropicum, and T. terrestre from wild boars. Based on the low prevalence of keratinophilic fungi, wild boars probably are not of special epizootological interest for dermatophytic infections.

The yeast, Cryptococcus neoformans, was found in apparently healthy birds at the Jos Wildlife Park and Zoo in Jos, Nigeria. Cryptococcus neoformans var neoformans was isolated from feces of four captive bird species. Five isolates belonged to serotype A while two were serotype D. Serotype A of C. neoformans was isolated from a white face duck (Dendrocygna viduata), eagle owl (Bubo africanus cinerascene) and peacock (Pavo cristatus). The other two (serotype D), were isolated from a spotted eagle owl.

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.

Tasmanian native marsupials were screened for the presence of Giardia spp. over a 3 yr period, revealing a 21% prevalence in the 295 animals tested. A pilot study of experimentally infected eastern barred bandicoots (Perameles gunnii) indicated susceptibility to infection with Giardia duodenalis from a human source.

Thin smears of blood were examined from 157 wood ducks (Aix sponsa) trapped at Savannah National Wildlife Refuge (South Carolina, USA) and Harris Neck National Wildlife Refuge (Georgia, USA) during spring and summer, 1994 and 1995. Thirteen wood ducks (8%) were infected with blood parasites. Eleven of these birds were infected with Haemoproteus nettionis, seven with Leucocytozoon simondi, and five with unidentified microfilariae. Additionally, eight wood ducks (5%) were infected with Haemoproteus greineri. This is the first record of H. greineri in anatids trapped along the Atlantic Flyway south of Labrador and the first record of this species in wood ducks. To further characterize the distribution of H. greineri in the wood duck, blood smears were examined from hatching year ducks trapped at 10 different Atlantic flyway locations during spring and summer, 1980 to 1983. Haemoproteus greineri was found in wood ducks trapped in all 10 locations which extend from 46°N latitude in New Brunswick to 37°N latitude in Virginia. These findings indicate that H. greineri is not exclusively boreal in distribution, but also is found, at least in wood ducks, along much of the Atlantic Flyway.

During the slaughtering season of February and March 1991, 559 capybaras (Hydrochoerus hydrochaeris) were tested for Trypanosoma evansi in two areas in Venezuela: El Frio Ranch and El Cedral Ranch. Blood and serum samples were evaluated for T. evansi. Forty-eight (9%) of 559 capybaras had T. evansi using the microcentrifugation technique. Further, 279 (50%) of the 559 capybaras had antibodies against T. evansi immunofluorescence test in both ranches. Thus, capybaras may be important in the epizootiology of T. evansi in this enzootic area.

The tissue locations and effects produced by metacercariae of Diplostomum (Austrodiplostomum) mordax and Tylodelphys destructor in the brain of 30 silversides (Basilichthys australis) from Lake Riñihue in Chile, were evaluated. Metacercariae were mainly observed in the interlobular infoldings, meninges and ventricles of the brain. The prevalence was 18 (60%) and the intensities were usually low (1 to 9 metacercariae), with no inflammation or invasion of the parenchyma, except for one fish which had 130 parasites associated with a moderate inflammatory reaction. Asymmetry in the distribution of metacercariae in the cerebral hemispheres was observed in one (3%) of the 30 fish.

In an effort to control Protostrongylus spp. in a Rocky Mountain bighorn sheep herd (Ovis canadensis canadensis) of approximately 30 animals, fenbendazole-medicated salt was placed on the Stillwater bighorn winter range in southcentral Montana (USA) for four consecutive winters, 1990 to 1993. Sheep of all age and sex classes were observed using the medicated salt throughout the study period. Prevalence and average number of lungworm larvae per gram of bighorn feces declined significantly (P < 0.05) from pretreatment levels (1987 to 1989), and remained low throughout the study period. Free-choice availability of fenbendazole-medicated salt is a potentially effective management tool for long-term control of protostrongylid lungworm.

An undescribed species of Demodex (Acari: Demodecidae) was observed in hair follicles and ducts of sebaceous glands in the ear canals of seven California ground squirrels (Spermophilus beecheyi) from Santa Clara Count); California (USA). The animals had died of unrelated causes and were submitted for necropsy between September 1994 and February 1996. Similar mites were observed in the lumens of hair follicles and ducts of Meibomian glands in the eyelids of two of these squirrels. Microscopic changes in the epithelium and surrounding dermis, when present, were minimal. No associated clinical signs of disease or macroscopic lesions were observed. To our knowledge, this is the first report of Demodex sp. in a ground squirrel.

Six species of chewing lice (Phthiraptera: Menoponidae, Philopteridae) are reported from four species of seabirds collected off the coast of Chile. They are Eidmanniella pellucida, Piagetiella transitans, and Piagetiella caputincisa, from a Guanay cormorant (Phalacrocorax bougainvillii); Harrisoniella ferox collected from a black-browed albatross (Diomedea melanophrys); Ancistrona vagelli from a white-necked petrel (Pterodroma externa); and Pelmatocerandra flinti collected from a Magellan diving petrel (Pelecanoides magellani). Eidmanniella pellucida and P. transitans are reported from Chile for the first time. Piagetiella caputincisa from the Guanay cormorant may be a contaminant from a red-legged shag (Phalacrocorax gaimardi).

Ectoparasites were collected from ospreys (Pandion haliaetus) in four study areas within the Great Lakes basin of Ontario, Canada. Two parasitic mite (Acari) species, Bonnetella fusca and Analloptes sp., were collected from nestlings. One chewing louse (Mallophaga) Kurodaia haliaeeti was collected from nestlings and adults. Prevalence and intensity of K. haliaeeti were greater in the most northern of the four study areas. Bonnetella prevalence and intensity did not seem to vary greatly across the study areas. New range and host records are presented for B. fusca and Analloptes sp., respectively.

We sampled sympatric bighorn sheep (Ovis canadensis, n = 31), mule deer (Odocoileus hemionus, n = 38), and domestic cattle (n = 26) in the San Bernadino Mountains of southern California (USA) for the presence of Psoroptes spp. mites and for serologic evidence of exposure to bluetongue virus (BTV) and Babesia spp. From 1991 through 1994, Psoroptes spp. infestations were found on 12 (44%) of 27 bighorn sheep. No mites were found on mule deer or cattle. The BTV serum antibody prevalence in a cohort of 26 cattle ranged from 17 to 89%. There was no evidence of exposure to BTV in the bighorn sheep or mule deer. The cumulative serum antibody prevalence of Babesia spp. during the study was 35% in 26 bighorn sheep and 85% in 20 mule deer, while antibodies were not detected in a cohort of cattle when they were sampled in May (n = 23) and December (n = 22) of 1992. Based on these results, we concluded that infestation with Psoroptes spp. and exposure to BTV was limited to bighorn sheep and cattle, respectively. In contrast, Babesia spp. infections appeared to be common in both mule deer and bighorn sheep while there was no evidence of exposure in cattle.