Characterization of Anaplasma marginale isolated from North American bison

Anaplasma marginale (Rickettsiales: Anaplasmataceae), a tick-borne pathogen of cattle, is endemic in tropical and subtropical regions of the world. Although serologic tests have identified American bison, Bison bison, as being infected with A. marginale, the present study was undertaken to confirm A. marginale infection and to characterize isolates obtained from naturally infected bison in the United States and Canada. Major surface protein (MSP1a and MSP4) sequences of bison isolates were characterized in comparison with New World cattle isolates. Blood from one U.S. bison was inoculated into a susceptible, splenectomized calf, which developed acute anaplasmosis, demonstrating infectivity of this A. marginale bison isolate for cattle. The results of this study showed that these A. marginale isolates obtained from bison were similar to ones from naturally infected cattle.     

Characterization of Anaplasma marginale Isolated from North American Bison

Anaplasma marginale (Rickettsiales: Anaplasmataceae), a tick-borne pathogen of cattle, is endemic in tropical and subtropical regions of the world. Although serologic tests have identified American bison, Bison bison, as being infected with A. marginale, the present study was undertaken to confirm A. marginale infection and to characterize isolates obtained from naturally infected bison in the United States and Canada. Major surface protein (MSP1a and MSP4) sequences of bison isolates were characterized in comparison with New World cattle isolates. Blood from one U.S. bison was inoculated into a susceptible, splenectomized calf, which developed acute anaplasmosis, demonstrating infectivity of this A. marginale bison isolate for cattle. The results of this study showed that these A. marginale isolates obtained from bison were similar to ones from naturally infected cattle.     

Experimental infections of Babesia bigemina in American bison

Babesia bigemina was experimentally transmitted from cattle to bison and back to cattle. One spleen-intact and two splenectomized American bison (Bison bison) inoculated with a B. bigemina stabilate exhibited clinical and hematological signs of babesiosis within 10 days of exposure. Blood from the infected bison produced disease in a splenectomized bovine steer.     

Bovine coccidia in American bison.

Three species of coccidia, found in American bison sampled in Wyoming, are identified. The described coccidial species, common to cattle, have not been reported previosuly from American bison, (Bison bison). Identification of the parasites was determined by oocyst structural measurements and by oocyst sporulation times.     

Detection of mitochondrial DNA from domestic cattle in bison on Santa Catalina Island

In 1924, 14 American bison (Bison bison) were introduced to Santa Catalina Island, California and sporadically supplemented thereafter with additional animals. To reduce the herd and its impact on native vegetation, over 2000 animals have been exported during the past four decades. Today, the herd is estimated to contain around 250 individuals. Genetic analysis was performed on 98 animals removed from the island in 2004. Forty-four samples (45%) had domestic cattle mitochondrial DNA (mtDNA), 12 (12%) had previously reported bison haplotypes and 42 (43%) had a new haplotype differing by one base pair from a previously reported bison haplotype. A complement of five restriction enzymes was found to be useful in identifying bison with domestic cattle mtDNA.     

Post-bottleneck mtDNA diversity in a free-living population of European bison: implications for conservation

A free-living population of European bison Bison bonasus in the Białowieża Primeval Forest originated from only seven founder animals after a severe bottleneck that occurred at the beginning of the 20th century. Consequently, the contemporary population of the species is characterized by low genetic diversity. We studied a total of 195 individuals (127 males and 68 females). A 1429 bp fragment of mitochondrial DNA (mtDNA) including the D-loop region was analyzed in 87 individuals and revealed only three distinct haplotypes. Nucleotide ( π ) and haplotype ( H _d) diversity values were estimated for the European bison and were compared with π and H _d estimated from three individuals of American bison Bison bison . Very low diversity values were found in the European bison in comparison with the diversity values found in the American bison. The low mtDNA variability in the European bison is in concordance with theoretical expectations for a species that has undergone a severe and recent bottleneck. A management strategy for the preservation of the rare and very rare haplotypes present in the Białowieża population of the European bison is discussed. Furthermore, all 195 individuals were investigated for heteroplasmy involving these three haplotypes, in order to detect a possible association between heteroplasmy and the incidence of males affected by posthitis , a disease that affects the male reproductive organs, leading to necrotic lesions. Heteroplasmy was found in 15 females, in 17 males affected by posthitis and in 11 non-affected males, and no significant association was found.     

Genetic Analysis of the Henry Mountains Bison Herd

Wild American plains bison (Bison bison) populations virtually disappeared in the late 1800s, with some remnant animals retained in what would become Yellowstone National Park and on private ranches. Some of these private bison were intentionally crossbred with cattle for commercial purposes. This forced hybridization resulted in both mitochondrial and nuclear introgression of cattle genes into some of the extant bison genome. As the private populations grew, excess animals, along with their history of cattle genetics, provided founders for newly established public bison populations. Of the US public bison herds, only those in Yellowstone and Wind Cave National Parks (YNP and WCNP) appear to be free of detectable levels of cattle introgression. However, a small free-ranging population (~350 animals) exists on public land, along with domestic cattle, in the Henry Mountains (HM) of southern Utah. This isolated bison herd originated from a founder group translocated from YNP in the 1940s. Using genetic samples from 129 individuals, we examined the genetic status of the HM population and found no evidence of mitochondrial or nuclear introgression of cattle genes. This new information confirms it is highly unlikely for free-living bison to crossbreed with cattle, and this disease-free HM bison herd is valuable for the long-term conservation of the species. This bison herd is a subpopulation of the YNP/WCNP/HM metapopulation, within which it can contribute significantly to national efforts to restore the American plains bison to more of its native range.     

Maternal and paternal lineages in cross-breeding bovine species. Has wisent a hybrid origin?

The tribe Bovini comprises cattle and cattle-like species. Reconstructions of their phylogeny have so far been incomplete and have yielded conflicting conclusions about the relationship of American bison and wisent (European bison). We have compared the sequences of three mitochondrial and two Y-chromosomal DNA segments. Mitochondrial DNA indicates that four distinct maternal lineages diverged after an early split-off of the buffalo species, leading to (1) taurine cattle and zebu, (2) wisent, (3) American bison and yak, and (4) banteng, gaur, and gayal, respectively. At a higher level, lineages (1) and (2) and lineages (3) and (4) are probably associated. In contrast, Y-chromosomal sequences indicate a close association of American and European bison, which is in agreement with their morphological similarity, complete fertility of hybrid offspring, and amplified fragment length polymorphism (AFLP) fingerprints of nuclear DNA. One explanation for the anomalous divergence of the mitochondrial DNA from the two bison species is lineage sorting, which implies that two distinct mitochondrial lineages coexisted in the bison-yak branch until the recent divergence of American bison and wisent. Alternatively, the wisent may have emerged by species hybridization initiated by introgression of bison bulls in another ancestral species. This "transpatric" mode of species formation would be consistent with the recent appearance of the wisent in the fossil record without clearly identifiable ancestors.     

Host defense function in neutrophils from the American bison (Bison bison)

Selected host defense functions of neutrophils isolated from American bison (Bison bison) were characterized and compared with those of cattle (Bos taurus). Bison neutrophils had a robust chemotactic response to both IL-8 and LTB(4), with maximal responses occurring at 10(-7) M (IL-8) and 10(-8) M (LTB(4)). The magnitude of the chemotactic response to IL-8 was similar in bison and bovine neutrophils (except at 10(-7) M IL-8, where bison had a stronger response). In response to LTB(4), bison neutrophils had a much stronger chemotaxis at both 10(-8) and 10(-7) M than did bovine cells. Production of reactive oxygen species (ROS) in response to phorbol myristate acetate (PMA) and opsonized zymosan (OpZ) was similar between bison and bovine neutrophils. However, the production of ROS in bison neutrophils stimulated with OpZ was primarily intracellular, while extracellular release of ROS was evident in bovine neutrophils stimulated with OpZ. Like bovine neutrophils, bison neutrophils did not generate a respiratory burst in response to fMLF. Granules prepared from bison neutrophils had potent direct killing action on the Gram-negative bacteria Escherichia coli but failed to kill the Gram-positive bacteria Staphylococcus aureus and, at intermediate doses, actually had a permissive effect for this bacteria. Thus, bison neutrophils have potent host defense capabilities similar in quality to those of bovine neutrophils; however, unique differences are present, which may allow bison neutrophils to respond to the distinct immunological challenges that bison encounter.     

Duration of bluetongue viremia in experimentally infected American bison.

Six yearling American bison (Bison bison bison) bulls and one yearling ewe (Ovis aries) were inoculated intradermally and subcutaneously with 2 x 10(5) plaque forming units (pfu) of bluetongue (BT) virus serotype 11. Two uninoculated yearling bison bulls served as negative controls. Blood samples were collected for serology and virus isolation on 0, 4, 7, 11 and 14 days post-inoculation (dpi) and every 2 wk thereafter to 127 dpi. Every 4 wk a new ewe was inoculated with a pooled sample of whole blood from the six infected bison, and each sheep was monitored for 28 days for clinical signs of BT and seroconversion. Bluetongue viremia was detected in all six inoculated bison starting at 4 to 28 dpi and was no longer detectable from 42 dpi onward. Pooled blood samples collected at 28, 56, 84 and 112 dpi from the six infected bison were not infectious for sheep. The six infected bison seroconverted by 11 to 28 dpi on a competitive enzyme-linked immunosorbent assay and by 28 dpi on the serum neutralization test, and all remained seropositive thereafter. No clinical signs or lesions attributable to BT were observed in the infected bison or controls. There was evidence that a small amount of epizootic hemorrhagic disease virus type 2 had been present in the BT virus inoculum; reasons are given for concluding that this did not affect the results of the BT study.     

Validation of 15 microsatellites for parentage testing in North American bison, Bison bison and domestic cattle

Fifteen bovine microsatellites were evaluated for use in parentage testing in 725 bison from 14 public populations, 178 bison from two private ranches and 107 domestic cattle from five different breeds. The number of alleles per locus ranged from five to 16 in bison and from five to 13 in cattle. On average, expected heterozygosity, polymorphism information content (PIC) and probability of exclusion values were slightly lower in bison than in cattle. A core set of 12 loci was further refined to produce a set of multiplexed markers suitable for routine parentage testing. Assuming one known parent, the core set of markers provides exclusion probabilities in bison of 0.9955 and in cattle of 0.9995 averaged across all populations or breeds tested. Tests of Hardy-Weinberg and linkage equilibrium showed only minor deviations. This core set of 12 loci represent a powerful and efficient method for determining parentage in North American bison and domestic cattle.     

Brucella abortus in Bison. II. Evaluation of strain 19 vaccination of pregnant cows

Protection against Brucella abortus induced abortion and infection provided by strain 19 (S19) vaccination was evaluated in American bison (Bison bison). Forty-eight pregnant bison were manually inoculated (MI) with S19 vaccine, 44 were ballistically inoculated (BI) with an absorbable hollow pellet containing lyophilized S19, and 46 were manually injected with buffered saline as non-vaccinated controls (NVC). All bison were Brucella spp. seronegative prior to the experiment, in the second trimester of pregnancy, and were randomly assigned to experimental groups. Approximately 60 days post-vaccination, abortions were observed in the vaccinated bison. Brucella abortus strain 19 was recovered from a bison that had recently aborted, her fetus, and from 11 of 12 other aborted fetuses. Fifty-eight percent (53 of 92) of vaccinated bison aborted, and no abortions were observed in the NVC bison. One cow aborted during her second post-vaccinal pregnancy and S19 was identified from the dam and fetus indicating that chronic S19 infections can occur in bison. Positive antibody titers were present 10 mo post-vaccination in 73% (66 of 91) of the bison. Thirteen mo post-vaccination, 30 MI vaccinates, 27 BI vaccinates, and 30 NVC bison were challenged during the second trimester of pregnancy with 1 x 10(7) CFU of B. abortus strain 2308 via bilateral conjunctival inoculation. Protection against abortion was 67% (P less than or equal to 0.0001) for vaccinated bison compared to 4% in NVC. Protection against B. abortus infection was determined to be 39% (P greater than or equal to 0.001) for vaccinates and 0% (zero of 30) for NCV. Persistent antibody titers, vaccine induced abortions, and chronic S19 infections indicate that the S19 vaccine doses used in this study are not suitable for pregnant bison.     

Experimental anaplasmosis in American bison: persistence of infections of Anaplasma marginale and non-susceptibility to A. ovis

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.     

Conservation genomics: disequilibrium mapping of domestic cattle chromosomal segments in North American bison populations

Introgressive hybridization is one of the major threats to species conservation, and is often induced by human influence on the natural habitat of wildlife species. The ability to accurately identify introgression is critical to understanding its importance in evolution and effective conservation management of species. Hybridization between North American bison (Bison bison) and domestic cattle (Bos taurus) as a result of human activities has been recorded for over 100 years, and domestic cattle mitochondrial DNA was previously detected in bison populations. In this study, linked microsatellite markers were used to identify domestic cattle chromosomal segments in 14 genomic regions from 14 bison populations. Cattle nuclear introgression was identified in five populations, with an average frequency per population ranging from 0.56% to 1.80%. This study represents the first use of linked molecular markers to examine introgression between mammalian species and the first demonstration of domestic cattle nuclear introgression in bison. To date, six public bison populations have been identified with no evidence of mitochondrial or nuclear domestic cattle introgression, providing information critical to the future management of bison genetic resources. The ability to identify even low levels of introgression resulting from historic hybridization events suggests that the use of linked molecular markers to identify introgression is a significant development in the study of introgressive hybridization across a broad range of taxa.     

Evaluation of an animal protein-free semen extender for cryopreservation of epididymal sperm from North American bison (Bison bison)

The objective was to evaluate the suitability of an animal protein-free semen extender for cryopreservation of epididymal sperm from the two subspecies of North American bison: plains (Bison bison bison) and wood (Bison bison athabascae) bison. Both cauda epididymides (from six plains and five wood bison) were minced and incubated in Sp-TALPH buffer for approximately 2 h at 37 °C to release actively motile sperm. Sperm suspensions were filtered, centrifuged and the sperm pellet from each bull was divided into two fractions and diluted either in egg yolk containing extender, Triladyl, or in an animal protein-free extender, Andromed, and equilibrated for 20 min at 37 °C. Thereafter, samples were chilled and cryopreserved. Frozen-thawed sperm were evaluated for motility (computer assisted sperm analysis), viability (SYBR 14 and propidium iodide), acrosome integrity (FITC conjugated PSA), cryocapacitation (tyrosine phosphorylation of sperm proteins as a biomarker), and fertilizing ability (in a heterologous IVF system). There was no significant difference for progressive motility, viability, and acrosome integrity between the two extenders for plains bison (36.8 ± 9.0, 60.5 ± 17.4, and 77.3 ± 4.6%; overall mean ± SD) as well as for wood bison (11.7 ± 8.1, 13.7 ± 5.6, and 73.4 ± 4.2%). Levels of tyrosine phosphorylation did not differ for sperm preserved in the two extenders for both subspecies, although an inter-bull variability in the response to tyrosine phosphorylation between extenders was suggested for plains bison. Fertilization percent did not differ significantly between extenders for plains bison (84.16 ± 9.92%, overall mean ± SD) and for wood bison (59.53 ± 19.99%). In conclusion, in the absence of significant difference between extenders in post-thaw sperm characteristics, we inferred that Andromed (animal protein-free) was suitable for cryopreservation of epididymal sperm from North American bison.     

American bison influences on lepidopteran and wild blue lupine distribution in an oak savanna landscape

The natural influences of American bison have been virtually eliminated from the North American landscape, making it difficult to study native grassland ecosystems. The Sandhill Wildlife Area provides a unique opportunity to study this once-natural phenomenon in an oak savanna landscape. This area is home to the largest known population of the federally endangered Karner blue butterfly. We evaluated lepidopteran and lupine distribution relative to cover types and generated statistical models to predict occupancy and abundance relative to in situ groundcover variables as well as American bison related habitat variables. Overall variance of lepidopteran populations was best explained by increasing nectar and forb cover (29.4 % occurrence explained), while lepidopterans excluding Karner blues were further associated with decreasing cover of shrubs/trees (25.8 % occurrence, 59.8 % abundance explained) and were more likely to occur in areas of disturbance cover type. Karner blue occurrence was best explained (41.6 %) by increasing nectar and forb cover and an increasing number of bison chips (indicative of the recent presence of bison). Karner blue females, specifically, were more likely to be present in areas of wallow cover type and were best explained by increasing nectar plant cover (33.4 % occurrence, 60.1 % abundance explained) and increasing shrub cover. Females were also associated with an increasing number of bison chips, number of wallows and total size of wallows. Karner blue male occupancy were best explained (40.7 %) by increasing nectar cover and increasing number of bison chips. Lupine was significantly less likely to occur in areas of shrubs/trees cover. Lupine was explained (55.7 % occupancy and 88.2 % abundance), by the decreasing cover of shrubs/trees, and by the cover of nectar, forbs, and grass, and total size of wallows. We conclude that the activities caused by bison reduce the overall woody growth and produce improved habitat for nectar plants and especially for disturbance-dependent lupine, and subsequently enhance habitat for lepidopterans. Karner blues were significantly related to bison activities, suggesting that improved management techniques should consider mimicking megaherbivore activities through increased disturbance frequency and increase mineral-soil disturbance.     

Brucella abortus in captive bison. I. Serology, bacteriology, pathogenesis, and transmission to cattle

Two groups of six, non-brucellosis vaccinated, brucellosis seronegative pregnant American bison (Bison bison) were individually challenged with 1 x 10(7) colony forming units (CFU) of Brucella abortus strain 2308. Three days after challenge, each bison group was placed in a common paddock with six non-vaccinated, brucellosis susceptible, pregnant domestic heifers. In a parallel study, two groups of six susceptible, pregnant cattle were simultaneously challenged with the identical dose as the bison and each group was placed with six susceptible cattle in order to compare bison to cattle transmission to that observed in cattle to cattle transmission. Blood samples were collected from bison and cattle weekly for at least 1 mo prior to exposure to B. abortus and for 180 days post-exposure (PE). Sera from the bison and cattle were evaluated by the Card, rivanol precipitation, standard plate agglutination, standard tube agglutination, cold complement fixation tube, warm complement fixation tube, buffered acidified plate antigen, rapid screening, bovine conjugated enzyme linked immunosorbent assay, bison or bovine conjugated enzyme linked immunosorbent assay, and the hemolysis-in-gel techniques for the presence of antibodies to Brucella spp. At the termination of pregnancy by abortion or birth of a live-calf, quarter milk samples, vaginal swabs, and placenta were collected from the dam. Rectal swabs were collected from live calves, and mediastinal lymph nodes, abomasal contents and lung were taken at necropsy from aborted fetuses for culture of Brucella spp. These tissues and swabs were cultured on restrictive media for the isolation and identification of Brucella spp. Pathogenesis of brucellosis in bison was studied in an additional group of six pregnant bison which were challenged with 1 x 10(7) CFU of B. abortus strain 2308. One animal was euthanatized each week PE. Tissues were collected at necropsy and later examined bacteriologically and histologically. Lesions of brucellosis in bison did not significantly differ grossly or histologically from those in cattle. There were six abortions and two nonviable calves in the bison group, as compared to nine abortions in the 12 similarly inoculated cattle. As determined by bacterial isolations, transmission of B. abortus from bison to cattle (five of 12 susceptible cattle became infected) did not differ statistically from cattle to cattle transmission (six of 12 susceptible cattle became infected) under identical conditions. No single serologic test was constantly reliable to diagnosing B. abortus infected bison for 8 wk PE.(ABSTRACT TRUNCATED AT 400 WORDS)     

Seasonal Shifts in Diet and Gut Microbiota of the American Bison (Bison bison)

North American bison (Bison bison) are becoming increasingly important to both grassland management and commercial ranching. However, a lack of quantitative data on their diet constrains conservation efforts and the ability to predict bison effects on grasslands. In particular, we know little about the seasonality of the bison diet, the degree to which bison supplement their diet with eudicots, and how changes in diet influence gut microbial communities, all of which play important roles in ungulate performance. To address these knowledge gaps, we quantified seasonal patterns in bison diet and gut microbial community composition for a bison herd in Kansas using DNA sequencing-based analyses of both chloroplast and microbial DNA contained in fecal matter. Across the 11 sampling dates that spanned 166 days, we found that diet shifted continuously over the growing season, allowing bison to take advantage of the seasonal availability of high-protein plant species. Bison consumed more woody shrubs in spring and fall than in summer, when forb and grass intake predominated. In examining gut microbiota, the bacterial phylum Tenericutes shifted significantly in relative abundance over the growing season. This work suggests that North American bison can continuously adjust their diet with a high reliance on non-grasses throughout the year. In addition, we find evidence for seasonal patterns in gut community composition that are likely driven by the observed dietary changes.     

Hematology, blood chemistry and selenium values of captive pronghorn antelope, white-tailed deer and American bison

Pronghorn were observed to have a significantly higher whole blood selenium concentration than either the white-tailed deer or bison. Pronghorn colloid values were significantly less than those of the bison, and approached statistical significance for the white-tailed deer. Differential white blood cell counts for the white-tailed deer were markedly different from those of the pronghorn and bison. The American bison had significantly higher cortisol values and lower T3 values than either the white-tailed deer or pronghorn.     

Resistance to malignant catarrhal fever in American bison (Bison bison) is associated with MHC class IIa polymorphisms

The Rhadinovirus ovine herpesvirus-2 (OvHV-2) is the most common causative agent of malignant catarrhal fever (MCF) in clinically susceptible ruminants including cattle and bison. American bison (Bison bison) are highly susceptible to clinical MCF. Nevertheless, approximately 20% of bison on ranches or in feedlots become infected with the virus without developing clinical disease. Defining the genetic basis for differences in susceptibility between bison could facilitate development of improved control strategies for MCF. One genetic region that influences susceptibility to infectious diseases is the major histocompatibility complex (MHC). In this study, a Bison bison (Bibi) DRB3 oligonucleotide microarray was used to type 189 bison from 10 herds where MCF outbreaks had occurred. Binary logistic regression was used to classify DRB3 alleles as resistant (R), susceptible (S) or neutral (N). Animals were reclassified using six DRB3 genotype categories: N/N, N/R, N/S, R/S, R/R and S/S. Analysis of homogeneity across herds showed that there was a herd effect. Consequently, a penalized logistic regression model was run with herd and genotype categories as the explanatory variables. The R/R genotype was associated with resistance to MCF (P = 0.0327), while the S/S genotype was associated with clinical MCF (P = 0.0069). This is the first evidence that MHC class IIa polymorphism is associated with resistance or susceptibility to OvHV-2-induced MCF.