Toxoplasmic encephalitis in a free-ranging Rocky Mountain bighorn sheep from Washington

A 4-mo-old free-ranging Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from the Hells Canyon area (Washington, USA) was diagnosed with encephalitis associated with Toxoplasma gondii infection. The sheep had concurrent pneumonic pasteurellosis and resided in a geographic area with endemic Pasteurella-associated pneumonia and mortality in bighorn sheep. The brain had multifocal necrotizing and nonsuppurative encephalitis with intralesional protozoa. The protozoa were identified as T. gondii by immunohistochemistry. To our knowledge, this is the first report of T. gondii infection in a Rocky Mountain bighorn sheep.     

Seroprevalence of Toxoplasma gondii infection in domestic sheep in Durango State, Mexico

The seroprevalence of Toxoplasma gondii infection in sheep (Ovis aries) in northern Mexico is largely unknown. Antibodies to T. gondii were determined in serum samples from 511 sheep from 8 farms in Durango State, Mexico, using the modified agglutination test (MAT). Sheep were raised in 3 geographical regions, i.e., mountainous (n = 68), semi-desert (n = 132), and valley (n = 311). Overall, T. gondii antibodies were found in 77 (15.1%) of 511 sheep, with MAT titers of 1∶25 in 27, 1∶50 in 10, 1∶100 in 11, 1∶200 in 11, 1∶400 in 8, 1∶800 in 3, 1∶1,600 in 4, and 1∶3,200 in 3. The seroprevalence of T. gondii infection increased significantly with age, indicating post-natal transmission. In contrast, gender, breed, flock size, and geographic region did not significantly influence the seroprevalence. Seropositive sheep were found in 7 of 8 farms sampled. This is the first report of T. gondii infection in sheep in Durango State, Mexico. Results indicate that infected sheep are probably an important source of T. gondii infection for humans in Durango State.     

Seroprevalence and isolation of Toxoplasma gondii from sheep from São Paulo state, Brazil

Sheep are important in the epidemiology of Toxoplasma gondii infection but little is known of ovine toxoplasmosis in Brazil. Antibodies to T. gondii were assayed in sera of 495 sheep from 36 counties of S?o Paulo State, Brazil, using the modified agglutination test (MAT titer > or =1:25) and found in 120 (24.2%). Samples of brain, heart, and diaphragm of 82 seropositive sheep were pooled, digested in pepsin, and bioassayed in mice. Toxoplasma gondii was isolated from tissue homogenates of 16 sheep and the isolates were designated TgShBr1-16. Six of the 16 T. gondii isolates killed 100% of infected mice. Results indicate that asymptomatic sheep can harbor mouse-virulent T. gondii, and hence they can serve as a source of infection for humans.     

Genetic characterization of Anaplasma ovis strains from bighorn sheep in Montana

Wildlife reservoir species and genetic diversity of Anaplasma ovis (Rickettsiales: Anaplasmataceae) have been poorly characterized. Bighorn sheep (Ovis canadensis), captured in Montana from December 2004 to January 2005, were tested for antibodies to Anaplasma spp.; the presence of A. ovis was determined by the characterization of major surface protein msp4 sequences. Anaplasma antibodies were detected in 25/180 (14%) sampled bighorn sheep and A. ovis msp4 sequences were amplified by polymerase chain reaction (PCR) and sequenced from 9/23 (39%) of seropositive animals. All animals were negative by PCR for the related pathogens, Anaplasma phagocytophilum and Anaplasma marginale. All msp4 sequences identified in the bighorn sheep were identical and corresponded to a single A. ovis genotype that was identical to a sheep isolate reported previously from Idaho. The finding of a single genotype of A. ovis in this wild herd of bighorn sheep was in contrast to the genetic diversity reported for A. marginale in cattle herds in the western United States and worldwide. These results demonstrated that bighorn sheep may be a wildlife reservoir of A. ovis in Montana.     

Immunologic responses of domestic and bighorn sheep to a multivalent Pasteurella haemolytica vaccine

The efficacy of a Pasteurella haemolytica vaccine (serotypes A1, A2, and T10) to induce humoral antibodies and alter colonization of the upper respiratory tract by related P. haemolytica spp. strains was evaluated in 10 bighorn (Ovis canadensis canadensis) and 10 domestic (Ovis aries) sheep. Sheep of each species were divided into five pairs based on age and history of respiratory disease. One sheep in each pair was vaccinated twice 2 wk apart with 2 ml of vaccine (VAC group) and the remaining animals (NV group) were injected with 2 ml of sterile saline. Mild, transient lameness was the only observed adverse effect. Blood sera from the sheep were tested for agglutinating antibodies against whole cells of A1, A2, and T10 and for leukotoxin neutralizing antibodies. Antibody titers were expressed as the reciprocal log2 of the highest reactive dilutions. Domestic sheep > 1-yr-old and two bighorn sheep with a history of A1 infection had higher titers throughout the study against A1 cells than domestic sheep < 1-yr-old and bighorns without a history of A1 infection. Both domestic and bighorn sheep had log2 titers of 8 to 12 against A2 cells and 6 to 12 against T10 cells during this time. Bighorn sheep in the VAC group had 2 to 32 fold titer increases for A1 cells by 2 wk post-vaccination (PV) compared to 0 to 2 fold increases in VAC domestic sheep. Two to 16 and 0 to 8 fold increases in antibodies titers to A2 and T10 cells, respectively, were detected in sera of both VAC groups. Sera of bighorn sheep with a history of respiratory disease and all domestic sheep had log2 leukotoxin neutralizing antibody titers of 4 to 14 in contrast to < or = 2 in sera of bighorn sheep without a history of respiratory disease. Neutralizing antibody titers of two bighorns without a history of respiratory disease in the VAC group increased from log2 0 to 5 in one and from 0 to 9 in the other 2 wk PV. Antibody increases in these animals were no longer evident at 16 wk PV while titers of animals with histories of disease remained relatively stable. The types and numbers of Pasteurella spp. isolated from nasal and pharyngeal swabs varied throughout the study without conclusive evidence of suppression of colonization. Although the animals were not experimentally challenged to determine the efficacy of the vaccine, one VAC and one NV bighorn sheep died following introduction of an A2 P. haemolytica strain when leukotoxin neutralizing antibodies had returned to pre-vaccination levels. This vaccine appeared to be safe for use in bighorn sheep and stimulated moderate but transient increases in antibody levels which should provide some protection against naturally occurring disease. A vaccine which would induce production of high and maintained antibodies against multiple strains of P. haemolytica would be valuable for use in bighorn sheep maintained in captivity or when captured for relocation.     

A genome-wide set of SNPs detects population substructure and long range linkage disequilibrium in wild sheep

The development of genomic resources for wild species is still in its infancy. However, cross-species utilization of technologies developed for their domestic counterparts has the potential to unlock the genomes of organisms that currently lack genomic resources. Here, we apply the OvineSNP50 BeadChip, developed for domestic sheep, to two related wild ungulate species: the bighorn sheep (Ovis canadensis) and the thinhorn sheep (Ovis dalli). Over 95% of the domestic sheep markers were successfully genotyped in a sample of fifty-two bighorn sheep while over 90% were genotyped in two thinhorn sheep. Pooling the results from both species identified 868 single-nucleotide polymorphisms (SNPs), 570 were detected in bighorn sheep, while 330 SNPs were identified in thinhorn sheep. The total panel of SNPs was able to discriminate between the two species, assign population of origin for bighorn sheep and detect known relationship classes within one population of bighorn sheep. Using an informative subset of these SNPs (n=308), we examined the extent of genome-wide linkage disequilibrium (LD) within one population of bighorn sheep and found that high levels of LD persist over 4 Mb.     

Enzootic toxoplasmosis in sheep in north-central United States

Of 1,564 serum samples from adult ewes from 33 farms in Iowa, Minnesota, South Dakota, Kansas, and Nebraska where toxoplasmosis-induced ovine abortions had been diagnosed, 65.5% were found positive for Toxoplasma gondii antibodies using the modified agglutination test. Toxoplasma gondii antibody titers of ewes were: less than 64 (34.5%), 64 (14.9%), 256 (22.0%), 1,024 (14.5%), and greater than 4,096 (13.8%). Thus, 28.3% of sheep had high titers (greater than 1,024) indicating recently acquired T. gondii infection. On certain farms, up to 95% of ewes were seropositive. Prevalence of T. gondii antibodies increased with age of the ewe. Of 665 ewes, 53.6% of 1-yr-old ewes were seropositive (titers greater than 64) versus 75% of 5-yr-old ewes. Results indicate that T. gondii infection in sheep in the United States is widespread.     

Seroprevalence of Toxoplasma gondii in pigs, sheep, goats, and cattle from Grenada and Carriacou, West Indies

Prevalence of Toxoplasma gondii infection in pregnant women in Grenada is considered high. Little is known of the epidemiology of T. gondii infection in Caribbean Islands. Serum samples of 750 food animals in Grenada and Carriacou were tested for antibodies to T. gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT, 1∶25 or higher) were found in 23.1% of 247 pigs, 44.1% of 204 sheep, 42.8% of 180 goats, and 8.4% of 119 cattle. Seroprevalence increased with age, indicating postnatal acquisition of T. gondii. Antibody titers of 1∶200 or higher were present in 65 of 90 seropositive sheep, 61 of 77 seropositive goats, and 23 of 57 seropositive pigs. However, none of the cattle had a MAT titer of 1∶200, suggesting that bovines are a poor host for T. gondii. Results indicate that pigs, sheep, and goats could be important sources of T. gondii infection if their meat is consumed undercooked.     

High prevalence and abundant atypical genotypes of Toxoplasma gondii isolated from lambs destined for human consumption in the USA

Little information is available on the presence of viable Toxoplasma gondii in tissues of lambs worldwide. The prevalence of T. gondii was determined in 383 lambs (<1 year old) from Maryland, Virginia and West Virginia, USA. Hearts of 383 lambs were obtained from a slaughter house on the day of killing. Blood removed from each heart was tested for antibodies to T. gondii by using the modified agglutination test (MAT). Sera were first screened using 1:25, 1:50, 1: 100 and 1:200 dilutions, and hearts were selected for bioassay for T. gondii. Antibodies (MAT, 1:25 or higher) to T. gondii were found in 104 (27.1%) of 383 lambs. Hearts of 68 seropositive lambs were used for isolation of viable T. gondii by bioassay in cats, mice or both. For bioassays in cats, the entire myocardium or 500g was chopped and fed to cats, one cat per heart and faeces of the recipient cats were examined for shedding of T. gondii oocysts. For bioassays in mice, 50g of the myocardium was digested in an acid pepsin solution and the digest inoculated into mice; the recipient mice were examined for T. gondii infection. In total, 53 isolates of T. gondii were obtained from 68 seropositive lambs. Genotyping of the 53 T. gondii isolates using 10 PCR-restriction fragment length polymorphism markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) revealed 57 strains with 15 genotypes. Four lambs had infections with two T. gondii genotypes. Twenty-six (45.6%) strains belong to the clonal Type II lineage (these strains can be further divided into two groups based on alleles at locus Apico). Eight (15.7%) strains belong to the Type III lineage. The remaining 22 strains were divided into 11 atypical genotypes. These results indicate high parasite prevalence and high genetic diversity of T. gondii in lambs, which has important implications in public health. We believe this is the first in-depth genetic analysis of T. gondii isolates from sheep in the USA.     

Toxoplasmosis in Sheep

The presence of Toxoplasma gondii in the diaphragm was correlated with the dye test titres in 174 sheep. In 94 of these the presence of the parasite was also correlated with the haemoglobin (Hb) type. T. gondii was recovered from 3 % of the sheep with titres < 1/16, compared with 30 % of those with titres 1/16 and 70 % of those with titres ≥ 1/32. The results indicate that the distinction between serologically positive and negative individuals at a final serum dilution of 1/16 is justified. Some evidence was found that the parasite is easier to recover from dye test positive mature sheep than from dye test positive lambs. Of the 174 sheep, 143 were examined at random among 186 sheep culled or cast for age during a 4-year period from 1 flock in which the prevalence of Toxoplasma antibodies was representative for flocks in the southern Norway, and T. gondii was recovered from 53 (37 %) of these. It was concluded that 10—15 % of the lamb carcases and 25—37 % of the carcases from mature sheep in this country have T. gondii in their muscles detectable by the peptic digestion technique. A possible genetical influence on the infection was indicated by the higher frequency of recoveries of T. gondii from sheep with Hb type B than from sheep with the Hb types A or AB, but the number of individuals with Hb type B was too small to demonstrate statistically significant differences. The epidemiological importance of infected sheep carcases is discussed.     

Isolation of Pasteurella haemolytica from tonsillar biopsies of Rocky Mountain bighorn sheep

Isolations of Pasteurella haemolytica were compared from tonsillar biopsies versus nasal passages for 29 free-ranging Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from central Idaho. Overall, P. haemolytica was isolated from 11 (38%) of 29 sheep. Two (18%) of the 11 positive samples were from only nasal passages compared to eight (73%) from tonsillar biopsies. Pasteurella haemolytica biotype T was isolated from tonsils of nine sheep and from nasal biopsies. Pasteurella haemolytica biotype T was isolated from tonsils of nine sheep and from nasal passages of only one sheep. Two sheep were positive for P. haemolytica biotype A from nasal passages. Culturing tonsillar biopsies as compared to nasal swab samples was a more reliable technique in detecting P. haemolytica, especially biotype T, in bighorn sheep.     

Sharing of Pasteurella spp. between free-ranging bighorn sheep and feral goats

Pasteurella spp. were isolated from feral goats and free-ranging bighorn sheep (Ovis canadensis canadensis) in the Hells Canyon National Recreation Area bordering Idaho, Oregon, and Washington (USA). Biovariant 1 Pasteurella haemolytica organisms were isolated from one goat and one of two bighorn sheep found in close association. Both isolates produced leukotoxin and had identical electrophoretic patterns of DNA fragments following cutting with restriction endonuclease HaeIII. Similarly Pasteurella multocida multocida a isolates cultured from the goat and one of the bighorn sheep had D type capsules, serotype 4 somatic antigens, produced dermonecrotoxin and had identical HaeIII electrophoretic profiles. A biovariant U(beta) P.haemolytica strain isolated from two other feral goats, not known to have been closely associated with bighorn sheep, did not produce leukotoxin but had biochemical utilization and HaeIII electrophoretic profiles identical to those of isolates from bighorn sheep. It was concluded that identical Pasteurella strains were shared by the goats and bighorn sheep. Although the direction of transmission could not be established, evidence suggests transmission of strains from goats to bighorn sheep. Goats may serve as a reservoir of Pasteurella strains that may be virulent in bighorn sheep; therefore, goats in bighorn sheep habitat should be managed to prevent contact with bighorn sheep. Bighorn sheep which have nose-to-nose contact with goats should be removed from the habitat.     

Insects feeding on desert bighorn sheep, domestic rabbits, and Japanese quail in the Santa Rosa mountains of southern California.

Desert bighorn sheep (Ovis canadensis cremnobates), a domestic rabbit (Oryctolagus cuniculus), and Japanese quail (Coturnix japonica) were used as bait animals to collect blood-feeding flies in an area of active blue-tongue and epizootic hemorrhagic disease virus transmission. Precipitin tests were used to confirm the blood source where feasible. Eight species of Culicoides, members of the Leptoconops kerteszi group, Simulium spp., Anopheles franciscanus, and Stomoxys calcitrans were collected from the bighorn sheep. Feeding on the bighorn sheep by Culicoides brookmani (n = 25), C. variipennis (n = 6), C. cacticola (n = 1), and Simulium spp. (n = 3) was confirmed by precipitin testing. Primary species attacking the rabbit were C. brookmani, C. variipennis, and the L. kerteszi group. The quail were attacked primarily by members of the C. copiosus group and the L. kerteszi group.     

Infectious keratoconjunctivitis in bighorn sheep, Silver Bell Mountains, Arizona, USA

An infectious keratoconjunctivitis (IKC) epizootic in bighorn sheep (Ovis canadensis) occurred in the Silver Bell Mountains, Arizona, USA, from 1 December 2003 to 31 March 2004. We used standard culture methods and polymerase chain reaction (PCR) amplification of the 16S rRNA gene to test for the causative agents of IKC and other diseases reported to be associated with bighorn sheep populations. All bighorn sheep and domestic goat test results were negative except for Mycoplasma spp. and Branhamella spp. The culture and PCR results differed. Conjunctival swabs from four of 19 IKC-affected bighorn sheep tested by culture were positive for Mycoplasma spp., whereas 22 of 22 bighorn sheep samples tested by PCR were positive for Mycoplasma spp. None of 13 domestic goats tested positive by culture for Mycoplasma spp., whereas five of 16 tested positive by PCR. Three of 16 domestic goats and seven of 24 IKC-affected bighorn sheep tested positive for Branhamella spp. by culture. Bighorn sheep began showing clinical signs of IKC between 21 and 28 days following initial detection of domestic goats in bighorn sheep habitat. The IKC epizootic lasted 122 days, and individual bighorn sheep were blind for an average of 38.4 days. Given the clear potential for disease transmission to bighorn sheep, we recommend that land managers not allow the pasturing of domestic goats near occupied bighorn sheep habitat.     

Effects of capture on biological parameters in free-ranging bighorn sheep (Ovis canadensis): evaluation of normal, stressed and mortality outcomes and documentation of postcapture survival

Blood samples and physiological data were collected from 634 bighorn sheep (Ovis canadensis) captured by four different methods between 1980 and 1986 in the western United States. These parameters were evaluated for selected physiological, biochemical and hematological values. Postcapture biological parameters were compared among bighorn sheep according to four different outcomes; normal, stressed or compromised, capture myopathy (CM) mortality, and accidental mortality. Significant differences (P less than 0.05) were noted between outcome groups relative to certain parameters: temperature, respiration, creatinine phosphokinase (CPK), lactic dehydrogenase (LDH), serum glutamic oxaloacetic transaminase (SGOT), blood urea nitrogen (BUN), glucose, white blood cell count (WBC) and plasma pH. Such differences between groups may help in evaluating the clinical status of bighorn sheep at capture, enabling one to predict those animals that might develop CM at a later date, indicate candidates for preventive medical treatment prior to release, and/or which should be followed closely to determine long-term survival. Evaluation of follow-up data (n = 77) related to outcome status and long-term survival of bighorn sheep indicated that less than 4% (3 of 77) were dead within 1 mo of capture (one of these had been classified as normal and two as stressed or compromised at capture); less than 3% (3 of 77) were dead greater than 1 mo, and less than 6 mo after capture two were classified in the stressed outcome and one as diseased. Eighty-eight percent (68 of 77) were alive from 1 mo to 5 yr after capture (53 were classified as normal, 12 as stressed or compromised and 3 as diseased), and 2% (1 of 77) had chronic CM but was still alive (this animal had been classified as normal). Of 77 sheep in the follow-up group, less than 3% (2 of 77) were not observed following capture (one was classified as normal and one as stressed and diseased). Of the fatalities, less than 3% (2 of 40) had been captured by the net-gun and less than 4% (1 of 27) by drive-net. Those two unobserved in the follow-up group also had been caught with the net-gun, 5% (2 of 40). The single surviving CM case had been captured by the net-gun. Although the net-gun appears to be one of the safest methods of capturing individual bighorn sheep, based on evaluation of capture data and biological parameters, it may not be associated with the best long-term survival in some bighorn sheep.(ABSTRACT TRUNCATED AT 400 WORDS)     

Seroprevalence of Toxoplasma gondii antibodies in wild dolphins from the Spanish Mediterranean coast

Although Toxoplasma gondii infection has been found occasionally in cetaceans, little is known of the prevalence of antibodies to T. gondii in wild dolphins. Antibodies to T. gondii were determined in serum samples from 58 dolphins stranded in the Spanish Mediterranean coast. Modified agglutination test was used to determine T. gondii antibodies, and a titer of 1:25 was considered indicative of T. gondii infection. Antibodies to T. gondii were found in 4 of 36 striped dolphins (Stenella coeruleoalba), in 2 of 4 common dolphins (Delphinus delphis), in 4 of 7 bottlenose dolphins (Tursiops truncatus), and in 1 harbour porpoise (Phocoena phocoena). Antibodies were not found in 9 Risso's dolphins (Grampus griseus) and in 1 long-finned pilot whale (Globicephala melas) surveyed. The results indicate that T. gondii infection is frequent in at least 3 dolphin species from the Mediterranean Sea.     

Desert bighorn sheep mortality due to presumptive type C botulism in California

During a routine telemetry flight of the Mojave Desert (California, USA) in August 1995, mortality signals were detected from two of 12 radio-collared female desert bighorn sheep (Ovis canadensis) in the vicinity of Old Dad Peak in San Bernardino County (California). A series of field investigations determined that at least 45 bighorn sheep had died near two artificial water catchments (guzzlers), including 13 bighorn sheep which had presumably drowned in a guzzler tank. Samples from water contaminated by decomposing bighorn sheep carcasses and hemolyzed blood from a fresh bighorn sheep carcass were tested for the presence of pesticides, heavy metals, strychnine, blue-green algae, Clostridium botulinum toxin, ethylene glycol, nitrates, nitrites, sodium, and salts. Mouse bioassay and enzyme-linked immunosorbent assay detected type C botulinum toxin in the hemolyzed blood and in fly larvae and pupae. This, coupled with negative results from other analyses, led us to conclude that type C botulinum poisoning was most likely responsible for the mortality of bighorn sheep outside the guzzler tank.     

Restoration Potential of Bighorn Sheep in a Prairie Region

Efforts to recover Rocky Mountain bighorn sheep (Ovis canadensis canadensis) throughout western North America have had limited success with the majority of current populations remaining in small and isolated areas on a fraction of their historical range. Prairie environments with rugged topography throughout the Northern Great Plains ecoregion were historically occupied by relatively robust bighorn sheep populations. We predicted there is likely unrealized potential habitat for restoring bighorn sheep to these areas; however, relatively little attention has been devoted to identifying habitat in unoccupied prairie regions. We used global positioning system (GPS)-collar data collected from 43 female bighorn sheep in 2 populations located in the eastern Montana, USA, portion of the Northern Great Plains during 2014–2018 to estimate a population-level annual resource selection model and identify the important factors affecting bighorn sheep resource selection. We extrapolated model predictions across eastern Montana's prairie region and identified potential habitat to understand restoration potential and assist with future translocations of bighorn sheep. Resource selection of bighorn sheep was most strongly associated with terrain slope and ruggedness, tree canopy cover, and a normalized difference vegetation index metric. Within currently unoccupied areas of the historical range, the model extrapolation predicted 7,211 km² of habitat, with most owned and managed by private landowners (44%), Bureau of Land Management (33%), and the United States Fish and Wildlife Service (15%). Our results provide an empirical evaluation of landscape covariates influencing resource selection of bighorn sheep occupying prairie environments and provide a habitat model that may be generalizable to other areas in the Northern Great Plains ecoregion. We demonstrate substantial potential for restoration opportunities of bighorn sheep in the Northern Great Plains ecoregion. Broad restoration of bighorn sheep across the ecoregion would likely require strong collaboration among and between public resource managers, private landowners, and livestock producers given the heterogeneous land ownership patterns, management strategies, and domestic sheep distributions. © 2020 The Wildlife Society.     

Serologic survey for Toxoplasma gondii and Neospora caninum in the common brushtail possum (Trichosurus vulpecula) from urban Sydney, Australia

The common brushtail possum (Trichosurus vulpecula) has well adapted to increasing urbanization, resulting in greater interaction with humans and their domestic pets. Wildlife species in urban areas face a higher risk of exposure to zoonotic pathogens and may be affected by parasites hosted by cats (Toxoplasma gondii) or dogs (Neospora caninum), yet it is unknown to what extent urban T. vulpecula are exposed to these parasites. Antibodies to T. gondii and N. caninum were assayed in sera of 142 adult possums from the city of Sydney, Australia. Using the modified agglutination test, antibodies to T. gondii were found in 9 (6.3%) of the 142 animals in titers of 1:25 (4), 1:50 (1), 1:100 (1), 1:800 (1), 1:3,200 (1), 1:6,400 (1), and 1:12,800 (1). Of some T. vulpecula multiple sera samples within a 2-yr frame could be collected, but seropositive animals in general were not recaptured after initial seroconversion. One possum had a high T. gondii titer on 2 consecutive bleedings, 14 mo apart, and seropositive possums appeared normal when captured. Sex seemed not to have an affect on antibody prevalence, but age and location may play a role. Antibodies to N. caninum were not detected in 1:25 dilution of sera in the N. caninum agglutination test, indicating that T. vulpecula may not have been exposed to this parasite. This is the first serological survey for T. gondii and N. caninum infections in urban T. vulpecula.     

Experimental contact transmission of Pasteurella haemolytica from clinically normal domestic sheep causing pneumonia in Rocky Mountain bighorn sheep

Two Rocky Mountain bighorn lambs (Ovis canadensis canadensis) were held in captivity for 120 days before being housed with two domestic sheep. The lambs were clinically normal and had no Pasteurella spp. on nasal swab cultures. The domestic sheep were known to carry Pasteurella haemolytica biotype A in the nasal passages. After being in close contact for 19 days. P. haemolytica biotype A was cultured from nasal swabs of one of the bighorn lambs. By 26 days, both bighorn sheep developed coughs, were anorectic and became lethargic and nasal swabs yielded P. haemolytica biotype T, serotype 10. Twenty-nine days after contact, the lambs were necropsied and found to have extensive fibrinous bronchopneumonia. From affected tissues pure cultures of beta-hemolytic P. haemolytica biotype T, serotype 10 were grown. Both domestic sheep remained clinically normal and had no gross or microscopic lesions, but they carried the same P. haemolytica serotype in their tonsils. Behavioural observations gave no indication of stress in the bighorn lambs.