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1.
Blood-feeding midges (Culicoides sp. and Leptoconops sp.) were sampled in the Santa Rosa Mountains, Riverside County, California (USA), to determine which species might be involved in the transmission of bluetongue and epizootic hemorrhagic disease viruses to peninsular bighorn sheep (Ovis canadensis cremnobates). Host-seeking midges were sampled with CO2-baited suction traps over a period of 30 mo. Nineteen species of Culicoides and seven of Leptoconops were collected. Five of the Culicoides sp. recovered are previously undescribed. The most abundant and widely distributed Culicoides sp. during spring (presumed virus transmission period to lambs) were C. (Selfia) brookmani, C. variipennis, C. (Avaritia) sp. (a new species near C. pusillus), and C. lahontan. Of these, C. brookmani (all elevations) and C. (Avaritia) sp. (elevations greater than 750 m) were common in the mountainous terrain inhabited by bighorn sheep. Culicoides variipennis, a vector of bluetongue virus in agricultural settings, and C. lahontan were numerous in sandy washes but were much less common in the mountains themselves. Leptoconops belkini and L. foulki were occasionally common in upper Deep Canyon in spring (April-June), while L. torrens was very abundant in the same area for 2 wk following heavy summer rains. Parity (an indicator of longevity and success in finding hosts and oviposition sites) in mountain areas was very low in C. variipennis (5%), low-moderate in C. (Avaritia) sp. (13%) and C. lahontan (21%), and relatively high in C. brookmani (40%). Vectorial capacity of Culicoides spp. for these hemorrhagic disease viruses is discussed, and it is suggested that species in addition to C. variipennis be considered as potential vectors of hemorrhagic disease viruses to desert bighorn sheep.  相似文献   

2.
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.  相似文献   

3.
Between 1978 and 1997, a combination of psoroptic scabies (Psoroptes spp.), mountain lion (Puma concolor) predation, and periodic drought reduced a population of native desert bighorn sheep (Ovis canadensis) in the San Andres Mountains (SAM), New Mexico, from >200 individuals to a single ewe. In 1999, this ewe was captured, ensured to be Psoroptes-free, and released back into the SAM. Eleven radio-collared rams were translocated from the Red Rock Wildlife Area (RRWA) in New Mexico into the SAM range and monitored through 2002 to determine whether Psoroptes spp. mites were still in the environment. None of these sentinel rams acquired scabies during this period, and no additional native sheep were found to be present in the range. In 2002, 51 desert bighorn sheep were translocated into the SAM from the Kofa National Wildlife Refuge in Arizona (n = 20) and the RRWA in New Mexico (n = 31). Twenty-one bighorn sheep have died in the SAM since that time, but Psoroptes spp. mites have not been detected on any of these animals, nor have they been found on mule deer (Odocoileus hemionus) sampled since 2000. We conclude that psoroptic scabies is no longer present in the San Andres bighorn sheep population and that psoroptic scabies poses a minimal to nonexistent threat to the persistence of this population at this time.  相似文献   

4.
Immunoblotting with defined antigens and antisera revealed extensive and nearly complete antigenic cross-reactivity between Psoroptes spp. mites from a bighorn sheep, a mule deer, a cow, and a rabbit. Antigenic differences were not detected between mites from the sympatric bighorn sheep and mule deer. However, minor antigenic differences between mites from the cow and rabbit suggested that these mites were distinct from each other, as well as from the mites from the bighorn sheep and mule deer. These results are consistent with earlier morphologic studies of these populations of mites and provide additional support for the hypothesis that putative populations and/or species of Psoroptes mites may not be reproductively or ecologically isolated, particularly when their hosts are sympatric.  相似文献   

5.
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.  相似文献   

6.
The biting gnat, Culicoides variipennis (Coquillett), was shown to be a vector of epizootic hemorrhagic disease (EHD) in white-tailed deer, Odocoileus virginianus, in Kentucky because of virus isolations from parous females. Epidemiological evidence showed a close relationship of this vector to the animal host during an outbreak of EHD in penned deer. Larval breeding sites of C. variipennis were found and C. variipennis was the most abundant biting fly present during the outbreak. Females of C. variipennis were commonly observed biting deer, swine, cattle and, occasionally, man.  相似文献   

7.
8.
Abstract. We investigated the identity and distribution of members of the Culicoides variipennis complex in the six New England states of the U.S.A., a region where bluetongue transmission has not been detected. Analyses of seven polymorphic isozyme-encoding loci showed that only C.v.variipennis , not considered to be a vector of the bluetongue viruses, was present. The populations of C.v.variipennis were significantly more hetero-zygous than C.v.sonorensis and Cv.occidentalis populations from similar studies in the state of California. Estimates of genetic diversity among populations of C.v.variipennis in New England were similar to C.v.sonorensis in the state of Colorado, but were significantly more genetically divergent than California populations of Cv.occidentalis. The impact of these findings on the status of New England as a possible bluetongue-free region for the purpose of international trade in ruminant livestock and their germplasm is discussed.  相似文献   

9.
A morphometric study of Psoroptes spp. mites was conducted to address difficulties encountered in species identification and to provide insights into the phylogenetic relationships between mites found on different hosts. A discriminant analysis employing 9 morphologic characters revealed that the lengths of the outer opisthosomal setae and the lateral margins of the opisthosomal knobs were the 2 most important characters for grouping mites according to host species. This analysis clearly separated mites collected from allopatric populations of bighorn sheep, rabbits, and cattle into discrete groups. However, differences were not detected between mites collected from sympatric populations of infested mule deer and bighorn sheep, suggesting that these mites were not host specific and represented a single interbreeding population. Differences also were not detected among mites collected from the ears and body of bighorn sheep and rabbits, demonstrating that the location of mites on a given host should not be used as a primary criterion in species identification.  相似文献   

10.
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.  相似文献   

11.
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.  相似文献   

12.
Six hundred thirty-four bighorn sheep (Ovis canadensis) were captured in the western United States between 1980 and 1986, using four different methods: drop-net (n = 158), drive-net (n = 249), chemical immobilization (n = 90) and net-gun (n = 137). The net-gun was found to have considerable advantages over the use of ground nets and chemical immobilization methods for capturing bighorn sheep. Evaluation of specific outcome categories for individual sheep, including normal, compromised (stress-induced), mortality from capture myopathy (CM), and accidental mortality, revealed significant differences in these rates between capture groups (P less than 0.05). The use of the net-gun resulted in the lowest proportion of compromised sheep at 11% (15/137), had no CM mortality, and resulted in a 2% (2/137) accidental mortality. The use of drop-nets resulted in 15% compromised sheep (24/158), a CM mortality rate of 2% (3/158), and an accidental mortality rate of 1% (2/158). A similar proportion of sheep were compromised with the drive-nets (16%, 39/249). This method also had the highest CM mortality rate at 3% (7/249), and an accidental mortality rate of less than 1% (2/249). Chemical immobilization resulted in the most compromised sheep at 19% (17/90), had a CM mortality rate of 2% (2/90), and caused the most accidental deaths at 6% (5/90). Drop-nets and drive-nets were comparable when combining total mortality with rates for compromised bighorn sheep, 18% and 19%, respectively (29/158 and 48/249). Chemical immobilization had the highest combined measure of risk at 27% (24/90) and net-gun lowest at 12% (17/137).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
Examples of the commercial trap Mosquito Magnet Pro (MMP emitting attractant 1-octen-3-ol in carbon dioxide 500 mL/min generated from propane fuel), were run 24 h/day on the Isle of Skye, Scotland, during June-August 2001 and evaluated for catching Culicoides biting midges (Diptera: Ceratopogonidae). From 30 days trapping, the catch averaged 2626 +/- 1358 Culicoides females/trap/day (mean +/- SE, range 558 +/- 139 to 6088 +/- 3597, for five sets of six consecutive nights), predominantly the pest Culicoides impunctatus Goetghebuer (68% overall), plus C. vexans (Staeger) > C. delta Edwards > C. pulicaris (L.) > C. lupicaris Downs & Kettle > C. albicans (Winnertz) > other Culicoides spp. Attempts were made to enhance the odour baiting system by adding hexane-extracts (2.1 mg/day) of hair samples from large host animals, resulting in the following effects on Culicoides collections: sheep - 53 %, red deer - 26 %, calf + 20%, pony + 40%, water buffalo + 262%, with greatest increases for C. impunctatus and C. pulicaris. Serial concentrations of these animal extracts (10(-1) - 10(-3) x 2.2 g/mL) were assayed on parous female C. impunctatus response in a Y-tube olfactometer (air-flow 150 mL/min), and by electroantennogram (EAG) on Culicoides nubeculosus Meigen laboratory-reared parous females. Positive behavioural responses to host odours were dose-dependent: the water buffalo extract being most active (threshold 0.22 g/mL), similar to deer, whereas other host extracts were > or = 10-fold less active. Correspondingly, the EAG threshold was lowest for water buffalo, 10-fold greater for deer, calf and pony, but not detected for sheep. If the active component(s) of these host extracts can be identified and synthesized, they might be employed to improve the capture of Culicoides midges for local control by removal trapping.  相似文献   

14.
Isolated, nonmigratory populations of bighorn sheep (Ovis canadensis) may experience high exposure to lungworms (Protostrongylus spp.) through a build-up of fecal material. However, semiarid climates may hinder lungworm transmission by limiting terrestrial gastropods, the intermediate hosts. We assessed potential for lungworm transmission, documented occurrence of transmission, and identified habitat types where transmission was likely to occur on ranges of two recently introduced populations of bighorn sheep in northern Utah. Gastropods were collected weekly on Antelope Island and the Newfoundland Mountains, May-August 2001-02, from each of the four major habitat types (riparian, rock, desert shrub, and grass). Distribution of 113 bighorn sheep groups was observed, and 421 fecal pellet groups were collected to estimate lungworm levels. A total of 1,595 gastropods representing five genera were collected from both ranges. Vallonia made up 85% of all gastropods collected. Of 980 gastropods collected on Antelope Island in 2002, only Vallonia were found infected with protostrongylid-type larvae (10 of 980=1%). Lungworm prevalence in bighorn fecal samples was 97% on Antelope Island and 90% on the Newfoundland Mountains. Lungworm prevalence in lambs indicated lungworm transmission was occurring on Antelope Island. Lungworm transmission was likely occurring in riparian habitat due to abundant gastropods, presence of infected gastropods, and reliance by bighorn sheep on few water sources. Differences in spatial distribution between ram and nursery groups may partly explain higher fecal larvae counts in nursery than in ram groups. We suggest lungworm levels in bighorn sheep on semiarid ranges may increase in dry years as bighorn sheep concentrate use on fewer perennial water sources.  相似文献   

15.
Nine species of Culicoides were aspirated from horses in Florida during the second phase of a study of equine Culicoides hypersensitivity (CHS). Approximately 90% of the 2933 midges were Culicoides insignis Lutz, 4% were C.stellifer (Coquillett), 3% were C.niger Root and Hoffman, 2% were C.alachua Jamnback and Wirth and the remaining 1% included C.venustus Hoffman, C.scanloni Wirth and Hubert, C.lahillei Iches (= C.debilipalpis Lutz), C.pusillus Lutz, and C.edeni Wirth and Blanton. Culicoides were sampled on seven farms located throughout Florida. The location and seasonality of lesion development on horses with CHS correlated with the Culicoides spp. collected directly from the horses as to their sites of attack, their seasonality and geographical distribution.  相似文献   

16.
To test the hypothesis that Mycoplasma ovipneumoniae is an important agent of the bighorn sheep (Ovis canadensis) pneumonia that has previously inevitably followed experimental commingling with domestic sheep (Ovis aries), we commingled M. ovipneumoniae-free domestic and bighorn sheep (n=4 each). One bighorn sheep died with acute pneumonia 90 days after commingling, but the other three remained healthy for >100 days. This unprecedented survival rate is significantly different (P=0.002) from that of previous bighorn-domestic sheep contact studies but similar to (P>0.05) bighorn sheep survival following commingling with other ungulates. The absence of epizootic respiratory disease in this experiment supports the hypothesized role of M. ovipneumoniae as a key pathogen of epizootic pneumonia in bighorn sheep commingled with domestic sheep.  相似文献   

17.
Lungs and fecal samples from nine hunter-killed Rocky Mountain bighorn sheep were examined for lungworms. All samples contained adults and/or larvae of Muellerius capillaris (Mueller, 1889). Protostrongylus spp., the lungworms commonly reported from bighorn sheep, were not present in any samples. Larvae of M. capillaris bear a spine on the dorsal side of the posterior end and are shorter than dorsal-spined larvae of other lungworms recorded from North American ungulates. Larvae similar in shape but longer than those of Muellerius were found in free-ranging bighorn sheep in Alberta and British Columbia. In addition, dorsal-spined larvae have been found in bighorn sheep in Montana, North Dakota, and Washington. The identity of the dorsal-spined larvae is known only from sheep in South Dakota. Thus, caution must be taken when diagnosing lungworm infections in Rocky Mountain bighorn sheep.  相似文献   

18.
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.  相似文献   

19.
Pasteurella multocida is a highly diverse group of bacteria recognized as important pathogens. Although P. multocida is not ordinarily associated with disease in Rocky Mountain bighorn sheep (Ovis canadensis canadensis), numerous isolates were cultured in high numbers from free-ranging bighorn sheep in the Hells Canyon area of Idaho, Washington, and Oregon (USA) during the winter of 1995-96. Animals captured in Hells Canyon and held in captivity, and their offspring, also harbored P. multocida. Biochemical utilization tests on 90 isolates identified three subspecies: P. multocida multocida a (n = 54); P. multocida multocida b (n = 13); and P. multocida gallicida (n = 15); and a non-speciated biotype, U6 (n = 8). Genomic DNA digestion with restriction endonuclease Hha I separated the isolates into 62 unique restriction fragment length polymorphism profiles. Capsular type A was predominant (72% of isolates). Only one isolate type, which may have been transmitted from a feral goat, was capsular type D, possessed the structural gene, toxA, for dermonecrotoxin detected by polymerase chain reaction, and produced toxin as determined by monoclonal antibody immunoblot. In conclusion, bighorn sheep in this study carried diverse types of generally non-toxigenic P. multocida associated with epizootic pneumonia.  相似文献   

20.
Bighorn sheep (Ovis canadensis) evolved for thousands of years in the presence of numerous predators, including mountain lions (Puma concolor). Bighorn sheep have presumably developed predator avoidance strategies; however, the effectiveness of these strategies in reducing risk of mountain lion predation is not well understood. These strategies are of increasing interest because mountain lion predation on bighorn sheep has been identified as a leading cause of mortality in some sheep populations. Therefore, we investigated how mountain lions affect both bighorn sheep habitat selection and risk of mortality in Arizona, USA. We used 2 approaches to investigate the predator-prey relationship between mountain lions and bighorn sheep. We fit 103 bighorn sheep (81 females and 22 males) with global positioning system radio-collars in 2 Arizona populations from 2013 to 2017, and used a negative binomial resource selection probability function to evaluate whether bighorn sheep selected for habitat features in accordance with presumed predator avoidance strategies, including terrain ruggedness, slope, topographic position, and horizontal obstruction, in 2 seasons (winter and summer). We then estimated how habitat features such as terrain ruggedness, slope, horizontal obstruction, and group size, influence the risk of mortality due to mountain lion predation using an Andersen-Gill proportional hazards model. Generally, both sexes selected areas with lower horizontal obstruction and intermediate ruggedness and slope, but selection patterns differed between seasons and sexes. The use of more rugged areas and steeper slopes decreased the risk of mortality due to mountain lion predation, consistent with presumed predator avoidance strategies. Increased group size decreased risk of bighorn sheep mortality due to mountain lion predation but this effect became marginal at approximately 10 individuals/group. We did not identify a relationship between horizontal obstruction and bighorn sheep mortality risk. Our findings can be used in habitat and population management decisions such as the prioritization of habitat restoration sites or selection of translocation sites. In addition, we suggest that augmentation of low-density bighorn sheep populations may reduce mountain lion predation risk by increasing group size, and that releasing large groups of bighorn sheep in population augmentation and reintroduction efforts may help to reduce mountain lion predation.  相似文献   

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