The pathogenicity of Brucella suis biovar 4 for bison

The pathogenicity of Brucella suis biovar 4 for bison (Bison bison) was evaluated by inoculation of 2.1 x 10(7) colony forming units (CFU) in 0.1 ml saline into the conjunctival sac of six pregnant cows. Six pregnant bison were inoculated with 1.27 x 10(7) CFU of Brucella abortus strain 2308 as a positive control. Bison were inoculated on 23 January 1992, and observed until calving or abortion after which they were euthanized, and necropsied. Bacteriological and histological examinations were conducted on lymph nodes, reproductive tract, mammary gland, and internal organs. Terminal serum samples from calves and cows were evaluated by card, rivanol precipitation, standard tube agglutination, cold complement fixation tube, indirect bison conjugated enzyme linked immunosorbent assay (ELISA), competitive ELISA, and particle-concentration fluorescence immunoassay. No clinical signs of brucellosis were seen in bison inoculated with B. suis biovar 4, and infection was found only in lymph nodes of two animals. There was no evidence of metastasis of this organism to the mammary gland or the reproductive tract. There were no detectable levels of antibodies to Brucella spp. in terminal blood samples taken from B. suis biovar 4-challenged bison. Brucella abortus was isolated from several tissues in all control bison. All B. abortus-challenged animals developed uterine infection and five developed mammary gland infection. Reproductive disease resulted in abortions in five B. abortus-challenged bison and neonatal death in the remaining calf. Brucella suis biovar 4 does not appear to be pathogenic for bison.

Experimental Brucella suis biovar 4 infection in a moose

A moose (Alces alces gigas) was inoculated with Brucella suis biovar 4 to better understand the effects of brucellosis in this species. Serum antibody titers increased rapidly and peaked within 21 to 56 days. Fever, leukocytosis, recumbency, anorexia and depression were observed starting 42 days post inoculation. Brucella suis biovar 4 was isolated from blood, lymph nodes, liver and spleen.

Serologic survey for Actinobacillus capsulatus in free-ranging snowshoe hares (Lepus americanus) from Alaska and Alberta

A plate agglutination method was developed to test sera from free-ranging snowshoe hares (Lepus americanus) captured in Alaska (USA) or Alberta (Canada) for antibody against Actinobacillus capsulatus. Antiserum against A. capsulatus was prepared in a domestic rabbit. A concentrated suspension of formalin-killed A. capsulatus was prepared for use as an antigen. Serum antibody prevalence for hares was 98 of 239 (41%) in Alaska and 51 of 111 (46%) in Alberta. Prevalence in Alaska peaked in 1981 corresponding to a peak in hare population density. Seasonal prevalence peaked in May in Alaska. Prevalence at one capture site in Alaska was significantly higher than at four other sites. There was no difference in sex-specific prevalence for either Alaska or Alberta.

Biogeography of island floras in the Great Lakes. II. Plant dispersal

Experimental and observational data were used to determine the adaptations for dispersal in each of the 335 vascular plant species in the flora of Barrier Island, a typical limestone island in the Great Lakes. Most have adaptations for more than one mode of dispersal. Adaptations for dispersal by water were found in 211 species (63% of the flora), and by birds in 205 species (61% of the flora); only 22 species (6.5% of the flora) do not appear to have effective adaptations for dispersal by either of these means. The other three modes of dispersal to these islands are by wind (14% of plant species), dispersal across snow and ice (10%), and by man (6%). Alien species (23% of the flora) show greater dependence on birds (85% of the alien species) and man (12% of the alien species) for dispersal than do native species (54 and 5%, respectively). Sea gulls, particularly the Herring Gull (Larus delawarensis Ord.), are the major factor in the introduction of the alien flora. The heavily disturbed habitats created in the nesting sites of both Herring and Ring-billed (Larus argentatus Pontoppidan) gulls favour the persistence of many alien plant species on these islands.

Biogeography of island floras in the Great Lakes. I. Species richness and composition in relation to gull nesting activities

Species–area relations of vascular plants and the effect of nesting colonies of gulls on plant species composition were investigated for 77 islands in Georgian Bay and Lake Huron in the Great Lakes region of Canada. The percentage of plant species classed as alien, annual, or biennial was significantly greater on islands with gull colonies. The slope of the species–area curve was significantly steeper on islands supporting gull colonies compared with islands lacking gull colonies. The expected decline in species richness with increased island remoteness was not detected statistically using multiple regression analysis. The difference in species–area slopes does not appear to reflect a lower propagule immigration rate to islands with gull colonies, because gulls are important in the dispersal of alien plant species to these islands. Larger islands with gull colonies tended to have richer floras than islands of similar size without gull colonies. It is suggested that on these larger islands the presence of gull colonies produces a gradient of soil nutrient and disturbance regimes, thus increasing habitat heterogeneity and species richness.

The effects of nesting gulls on the vegetation and soil of islands in the Great Lakes

The effects of nesting colonies of the Ring-billed Gull (Larus delawarensis Ord.) on vegetation and soil nutrients were monitored over a 4-year period on Barrier Island and other islands in Georgian Bay and Lake Huron, in the Great Lakes region of Canada. Nesting had a profound effect on the vegetation and species composition. Two distinct communities of annual alien species dominated the nesting sites, one flowering in May and June and the other from late August to October. Native species were rare in the nesting sites, in contrast to adjacent areas, where perennial native grasses were dominant. Factors favouring the replacement of indigenous vegetation by annual aliens include physical disturbance by gulls during nesting and deposition of guano, which caused dramatic increases in the levels of soil nutrients. Plant succession in nesting sites that had been abandoned for 3 and 4 years was characterized by a rapid decline in the abundance of annual aliens and their replacement by perennials. After the 2nd year native perennial grasses were dominant. Nutrient levels in the soil rapidly returned to near normal, except for phosphorus, which persisted at high levels. Herring Gull (Larus argentatus Pontoppidan) nests were also studied. Their density was much lower, and hence their effects were less pronounced. However, they supported a similar annual alien flora. Herring Gulls frequently nested on unvegetated cobble or gravel shores where the humus from the nests permitted the establishment of a permanent vegetation.

Trypanosoma cervi from Alaskan reindeer, Rangifer tarandus

Twenty-nine (64.4%) or 45 reindeer, Rangifer tarandus, examined over a two-year period were infected with trypanosomes. Trypomastigotes and dividing epimastigotes were found in the blood of fawns, cows, and bulls. Morphometric analysis of bloodstream trypomastigotes from reindeer and comparison of these parasites with similar stages of trypanosomes from elk, mule deer, and white-tailed deer from the continuous United States proved them conspecific; the trypanosomes from these members of the Cervidae are identified as Trypanosoma cervi Kingston & Morton, 1975. This is the first report of trypanosomes from reindeer. No pathogenic effects are known to be caused by these parasites.

Brucellosis in elk III. Serologic evaluation

The efficacy of the standard plate agglutination (SPT), buffered Brucella antigen rapid card (BBA), rivanol (Riv) and complement fixation (CFT) tests was statistically evaluated and correlated with known brucellosis infections in elk. Low titers on the SPT were detected in artificially exposed mature cow elk 2 weeks postinoculation and other tests began detecting antibodies at 3 weeks. Titers on all tests were detected as long as 4 years postinoculation. Serologic response was similar in artificially and naturally infected cows. Bulls did not maintain serologic titers as long as cows. The SPT at 1:25 or higher most frequently detected Brucella antibodies in infected elk, while the SPT at 1:100 or more least frequently detected antibodies. The percent of elk reacting at 1:100 or greater on the SPT declined rapidly after 6 months postinoculation. Combinations of any 2 of the 4 tests used had close agreement in concurrently identifying infected elk. The CFT correctly identified the greatest number (93%) of elk which were culture positive at necropsy and CFT titers persisted longer than those of the other tests. A CFT reaction persisted longer (average 10.7 weeks) than that of any other test in calves that demonstrated postnatal titers. The serologic responses of calves which acquired active infections were similar to adults. Criteria for identifying seropositive elk are discussed.

Effects of killed Brucella abortus strain 45/20 vaccine on reindeer later challenge exposed with Brucella suis type 4

Six seronegative pregnant reindeer (Rangifer tarandus L) were vaccinated with killed Brucella abortus strain 45/20 with added adjuvant. These were challenge exposed with B suis type 4 after 90 days; at the same time, 4 seronegative, nonvaccinated, pregnant reindeer (controls) were given the challenge inoculum. Humoral antibodies were detected in the vaccinated reindeer by postvaccination day 14. A marked increase in antibody levels also occurred after they were challenge exposed, but did not reach the levels observed in control reindeer which seroconverted within 8 days after they were given the challenge inoculum. One control reindeer aborted at 45 days after challenge exposure (at 165 days of a normal 225-day gestation period), and the fawn of another lived only a few days after delivery. Brucella suis type 4 was isolated from tissues of 3 of 4 control reindeer and of 2 of their fawns. All vaccinated reindeer gave birth to live fawns which were culture negative, although 1 fawn lived only a few days. Brucella suis type 4 was isolated from tissues of 1 vaccinated reindeer. Under the conditions of this experiment, killed B abortus 45/20 vaccine provided increased resistance to brucellosis.

Avian pox infection in an American green-winged teal (Anas crecca carolinensis) in Alaska

Poxvirus infection was diagnosed on the basis of gross and microscopic appearance plus the presence of typical inclusion bodies in a juvenile American green-winged teal (Anas crecca carolinensis) in Alaska. This constitutes the first known report of avian pox in migratory ducks and the first report of poxvirus infection in wild birds in Alaska.

HETEROCHROMATIC BANDING PATTERNS IN TWO SPECIES OF TRILLIUM

Giemsa stained chromosome segments of Trillium grandiflorum (Michx.) Salisb. and T. erectum L. were compared with the heterochromatic regions (H-segments) revealed by cold treatment. Several additional C-bands which did not correspond to the H-segments were observed. The centromeric bands were different in the two species.

Brucellosis in elk I. Serologic and bacteriologic survey in Wyoming

Incidence of brucellosis in elk (Cervus canadensis) on two winter feedgrounds in Wyoming was examined over a 5-year period by testing serum samples using the standard plate agglutination (SPT) buffered Brucella antigen (BBA), rivanol (Riv) and complement fixation (CFT) tests. Thirty-one percent of 1,165 elk were positive by defined criteria. Considering each test individually, only 29% (106) of 370 positive sera would have been classified as reactors by the SPT, 83% (307) by the BBA test and 86% (314) by the Riv test. The CFT would have identified 85% (267) of 332 positive samples on which it was used. Brucella abortus, type 1, was isolated from 17 of 45 elk necropsied. The SPT identified 59% (10) of these as reactors, the BBA test 94% (16) and the Riv test 88% (15). The CFT identified nine of nine (100%) on which it was used. Prevalence of sero-positive animals increased with age. Brucellosis has been present in one of the two elk herds since at least 1930, and the incidence of infection among mature females in both herds was approximately 50% during this study. No single serologic test should be relied upon to diagnose brucellosis in elk.

Trypanosoma cervi Kingston and Morton, 1975 from mule deer, Odocoileus hemionus, in Wyoming

Mensural values of blood stream stages and cross-transmission studies defined the trypanosome species from mule deer, Odocoileus hemionus, as con-specific with Trypanosoma cervi, the trypanosome found in elk from the same locality. Trypanosomes were found in eight mule deer sampled in the spring and eight sampled in the winter in southeastern Wyoming.

Further studies on trypanosomers in game animals in Wyoming

Blood samples were collected from captive and free-ranging elk (Cervus canadensis), mule deer (Odocoileus hemionus), white-tailed deer, (Odocoileus virginianus), black-tailed deer (Odocoileus hemionus columbianus), pronghorn (Antilocapra americana), moose (Alces alces), and bighorn sheep (Ovis canadensis) for cultural evidence of Trypanosoma sp. infection. Eleven of 188 (12%) hunter-killed elk, 22 of 37 (59%) free-ranging elk, and 79 of 119 (66%) captive elk were culture positive in 1973-74. Parasitemia in adult captive elk showed seasonal variation. Other captive or live-trapped animals found positive included 16 mule deer, two white-tailed deer, and one black-tailed deer. No pronghorn, moose, or bighorn sheep were positive. A 0.25 ml inoculum of elk blood was sufficient to give positive culture results. Small sample size may have contributed to negative results from elk trapped in March 1973.

Trypanosomes from mule deer, Odocoileus hemionus in Wyoming

Examination of mule deer, Odocoileus hemionus, from Wyoming in Spring, 1974 (8) and in Winter of 1974-75 (8) revealed trypanosomes in all 16 deer. Spring samples showed dividing epimastigotes as well as normal bloodstream forms. Winter samples showed only normal blood stream forms. These differences are considered to be seasonally related.

Trypanosoma cervi sp. n. from elk (Cervus canadensis) in Wyoming

Trypanosoma cervi sp. n. is described from 22 trypomastigote syntypes from the blood of elk, Cervus canadensis, in North America (type locality: Wyoming). The blood trypomatigotes of T. cervi are compared with various culture forms: epimastigotes in 22 to 25 C NNN cultures; trypomastigotes in 37 C NNN cultures; and trypomastigotes from CAM chick embryo (10-day) cultures. Trypanosoma cervi is differentiated on morphological grounds from the cosmopolitan bovine species, T. theileri, and from T. ingens and T. mazamarum. Transmission of T. cervi to cattle was attempted using infected elk blood. No trypanosomal stages were recovered when recipients were examined by blood culture. The findings support the morphological data that T. cervi is distinct from T. theileri.

THE CYTOLOGY OF STELLARIA LONGIPES

Stellaria longipes Goldie s.1. is a polyploid species complex with euploid and aneuploid chromosome numbers ranging from 2n = 51 to 107, the most frequent being 52, 78 and 104. Almost all the cytotypes show a near normal pollen and seed production and fertility. Meiotic irregularities in most plants are few and confined to the occurrence of a small number of univalents, trivalents and multivalents. Crosses between the main cytotypes are readily produced and usually show a near normal level of fertility in pollen and seed. All the naturally occurring cytotypes, together with several additional ones, have been produced in the artificial crosses. During pollen formation in some of the artificial hybrids, as well as in wild plants, a varying number of fertile monads and diads are produced. It is concluded that the range of chromosome numbers occurring in nature has arisen by hybridity between octoploids (2n = 104) and tetraploids (2n = 52), though it is probable that many of these hybrids are not of recent origin. The distribution of the cytotypes is discussed in relation to glaciation and it is noted that the octoploid tends to predominate near the edge of the range of distribution.