Coyotes as Sentinels for Monitoring Bovine Tuberculosis Prevalence in White-Tailed Deer

Abstract: Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), is endemic in free-ranging white-tailed deer (Odocoileus virginianus) in 5 counties (Alcona, Alpena, Montmorency, Oscoda, and Presque Isle) in the northeastern Lower Peninsula of Michigan, USA. The presence of a wildlife reservoir of tuberculosis in Michigan and the incidence of bTB in cattle (Bos taurus) resulted in Michigan losing its bTB accredited-free status. Subsequent wildlife surveillance programs identified relatively high disease prevalence in coyotes (Canis latrans), generating interest in their potential to serve as a sentinel species to detect bTB prevalence in white-tailed deer. Our goal was to develop an empirical basis for generating hypotheses about the spatial epidemiology of bTB infection in coyotes for future surveillance, management, and modeling efforts. Though variation in coyote home-range size may confound attempts to spatially correlate the incidence of disease in the sentinel and host species at a fine scale, overlap zones (OZs) between adjacent coyote home ranges may be the appropriate sample unit for spatially correlating disease prevalence in coyotes and white-tailed deer. Because overlapping home ranges are generally configured around resource rich (e.g., small mammals and white-tailed deer) timber management patches, the OZ concentrates spatial interaction between adjacent groups in a relatively small area. Furthermore, there is a direct relationship between interaction probabilities and the spatial dispersion of those patches. The latter finding provides a useful metric to incorporate into future efforts to develop spatially explicit models of bTB dynamics. Modeling efforts can then be used as a foundation to predict the epidemiological ramifications of alterations in intensively managed forested landscapes. (JOURNAL OF WILDLIFE MANAGEMENT 71(5):1545-1554; 2007)     

Correlations between Growth and Flowering in Chenopodium amaranticolor: II. Leaf and Stem Growth

Plants of Chenopodium amaranticolor grown in long photoperiodsfor 26 days were exposed to 0, 2, 6, or continuous short days(SD) and the resultant changes in leaf and stem growth on returnto long days recorded. Growth of the leaves, the main stem,and the axillary branches was initially strongly stimulatedby short days. Continued growth of leaves was inhibited by thedevelopment of flowers to anthesis; strong inhibition was observedafter 6 and continuous SDs, but not in the 2-SD or control groups,neither of which reached anthesis during the investigation. In the groups which flowered strongly, the intensity of inhibitionwas sufficient to mask completely the effect of the initialstimulation on final leaf and stem size. In the 2-SD group,however, lack of inhibition allowed full expression of the effectsof stimulation on the final leaf and stem dimensions. The system of stimulators and inhibitors controlling leaf growthprobably also brings about the changes in leaf shape associatedwith the onset of flowering. The results are discussed in relation to previous findings andit is suggested that similar stimulations of growth correlatedwith the induction of flowering might occur widely in both short-and long-day plants.     

TEMPERATURE-COMPENSATED TESTS FOR RAW MILK SUPPLIES. PART IV. STUDIES ON A KEEPING QUALITY TEST AT 19–20°

SUMMARY: A field-scale experiment carried out in Wales and the West Midlands, in which the temperature-compensated clot-on-boiling (C.O.B.) test of Rowlands & Hosking (1951) was applied to 11,626 samples of designated milk, morning, mixed and evening milk, gave proportions of failures in the ratio 1:2:3 respectively. Despite temperature compensation, failures varied according to atmospheric temperature from c. 50% at 72°F. or more to 10% at 56°F. or less and averaged 20% during the summer and 7% during the six winter months.
No marked differences were noted between the keeping qualities of tuberculin tested or accredited milk. During the winter no difference was found between producer-wholesaler and producer-retailer supplies, but the latter had a higher proportion of failures of evening and mixed milks during the summer.
In a set of 8,297 samples examined in addition by the methylene blue and coli-aerogenes tests, the C.O.B. test gave a lower incidence of failures than either the methylene blue or combined methylene blue and coli-aerogenes tests throughout almost the entire year. It is suggested that a temperature-compensated C.O.B. test is practicable as a routine procedure.     

COLI-AEROGENES BACTERIA FROM FARM DAIRY EQUIPMENT AND RAW MILK

SUMMARY: A series of 1,040 cultures of coli-aerogenes bacteria isolated at 30° from farm dairy equipment and raw milk was classified according to the recommendations of the Coliform Sub-Committee of the Society for Applied Bacteriology (Report, 1949). The distribution of species and types isolated from milk did not differ materially from that for dairy equipment, Klebsiella cloacae, K. aerogenes and Citrobacter freundii being the dominant species, while the incidence of Escherichia coli was relatively low. There was no marked seasonal incidence of any type, though E. coli I formed a slightly higher proportion of the coli-aerogenes microflora in winter, whereas K. aerogenes I was slightly higher in summer. Many of the cultures of the dominant types, K. cloacae, K. aerogenes I and Cit. freundii I, did not form acid and gas from lactose in two days at 37°. Consequently 37° negative, anaerogenic and paracolon strains constituted a relatively high proporton (49%) of the coli-aerogenes microflora.     

Flow- and substratum-mediated movement by a stream insect

1. In streams subject to frequent hydrologic disturbance, the ability of benthic invertebrates to disperse within the channel is key to understanding the mechanisms of flow refugium use and population persistence. This study focuses on crawling invertebrates, the effects on movement of abiotic factors (specifically, flow near the stream bed and bed micro‐topography) and the consequences for dispersal. 2. In a large flume, we observed individual cased caddisflies, Potamophylax latipennis, moving in fully turbulent flows over a precise replica of a water‐worked surface. From maps of movement paths, we quantified crawling behaviour and entrainment, and the influence of bed micro‐topography. We manipulated discharge and tested its effect on movement, linear displacement and areal dispersal. The highest discharge treatment was a disturbance to the caddis; the lowest discharge was not. Crawling behaviours were used to parameterise random walk models and estimate population dispersal, and to test the effects of abiotic factors on movement. 3. Bed micro‐topography influenced crawling in several ways. Caddis spent most of their time at the junctions between proud particles and the adjacent plane bed. The frequency distribution of turn angles was bimodal, with modal values approximating the angle required to travel around median‐sized particles. Larvae generally crawled downstream, but crawling direction relative to the flow was skewed by bed micro‐topography and was not directly downstream, unlike drift. 4. Caddis crawled for most of the time and discharge affected almost every aspect of their movement. As discharge increased, caddis crawled less often, more slowly and over shorter distances; they also became entrained more frequently and over greater distances. With increased discharge, caddis spent proportionately less time at the junctions between proud particles and the adjacent plane bed, and more time on the tops and sides of proud clasts. This is curious as most entrainment occurred from the tops and sides of clasts and entrainment is generally considered to be disadvantageous during disturbances. 5. Linear displacement (drift and entrainment combined) was downstream, but the relation between total displacement and discharge was complex. Total displacement decreased at intermediate discharge as crawling decreased, but increased at high discharge as entrainment and drift played a greater role in movement. 6. Within‐stream dispersal via crawling contained elements of both a correlated random walk (we observed directional persistence in turn angles) and a biased random walk (we observed downstream bias in move direction angles) and was best described as a biased correlated random walk. Dispersal was inversely related to discharge, suggesting that the ability of P. latipennis to crawl into flow refugia on the streambed is reduced at high flow.