Serologic survey for canine coronavirus in wolves from Alaska.

Wolves (Canis lupus) were captured in three areas of Interior Alaska (USA). Four hundred twenty-five sera were tested for evidence of exposure to canine coronavirus by means of an indirect fluorescent antibody procedure. Serum antibody prevalence averaged 70% (167/240) during the spring collection period and 25% (46/185) during the autumn collection period. Prevalence was 0% (0/42) in the autumn pup cohort (age 4-5 mo), and 60% (58/97) in the spring pup cohort (age 9-10 mo). Prevalence was lowest in the Eastern Interior study area. A statistical model indicates that prevalence increased slightly each year in all three study areas. These results indicate that transmission occurs primarily during the winter months, antibody decay is quite rapid, and reexposure during the summer is rare.     

Hunting practices increase the prevalence of Trichinella infection in wolves from European Russia.

From 1998 to 2000, 184 animals (82 wolves, 29 red foxes, 55 mustelids, 5 raccoon dogs, and 13 domestic dogs), mainly shot by hunters in the Tvier and Smoliensk regions of northwest European Russia, were tested for Trichinella larvae; 98 animals (53.3%) were found to be positive. The highest prevalence was detected in wolf (97.5%). Trichinella nativa was the most common species detected (98%). The diet of wolves was investigated by examining the stomach contents of 62 animals (75.6% of the total number of wolves examined for Trichinella). It consisted mainly of dog (36.4% of the total number of occurrences of all food items, PFO) and moose (31.2 PFO); however, during the hunting seasons of 1998-1999 and 1999-2000, skinned wolf carcasses were left in the forest as bait (567 carcasses, about 18,000 kg). This very high prevalence of Trichinella infection, the highest ever detected in a natural population of carnivores, could be explained by carnivore-carnivore transmission, influenced by the hunting practices adopted in the study area.     

Serologic survey for Toxoplasma gondii in lynx from interior Alaska

Two hundred fifty-five lynx (Felis lynx) carcasses were collected from trappers in Interior Alaska (USA). Serosanguinous fluids were collected from the chest cavity of each carcass. These fluids were tested for evidence of exposure to Toxoplasma gondii by means of a modified agglutination test using formalin fixed tachyzoites and mercaptoethanol. Thirty-nine of the samples had titers greater than or equal to the threshold (> or = 25). Antibody prevalence differed between areas, and was directly related to age of the host.     

Moss functioning in different taiga ecosystems in interior Alaska

Summary Carbon dioxide exchange rates in excised 2-year-old shoot sections of five common moss species were measured by infrared gas analysis in mosses collected from different stands of mature vegetation near Fairbanks, Alaska. The maximum rates of net photosynthesis ranged from 2.65 mg CO₂ g^-1h^-1 in Polytrichum commune Hedw. to 0.25 in Spagnum nemoreum Scop. Intermediate values were found in Sphagnum subsecundum Nees., Hylocomium splendens (Hedw.) B.S.G., and Pleurozium schreberi (Brid.) Mitt. Dark respiration rates at 15°C ranged from 0.24 mg CO₂ g^-1h^-1 in S. subsecundum to 0.57 mg CO₂ g^-1h^-1 in H. splendens. The dark respiration rates were found to increase in periods of growth or restoration of tissue (i.e., after desiccation). There was a strong decrease in the rates of net photosynthesis during the winter and after long periods of desiccation.Due to increasing amounts of young, photosynthetically active tissue there was a gradual increase in the rates of net photosynthesis during the season to maximum values in late August. As an apparent result of constant respiration rates and increasing gross photosynthetic rates, the optimum temperature for photosynthesis at light saturation and field capacity increased during the season in all species except Polytrichum, with a corresponding drop in the compensation light intensities. Sphagnum subsecundum seemed to be the most light-dependent species.Leaf water content was found to be an important limiting factor for photosynthesis in the field. A comparison between sites showed that the maximum rates of net photosynthesis increased with increasing nutrient content in the soil but at the permafrostfree sites photosynthesis was inhibited by frequent moisture stress.     

Endophytic bacillus sp. isolated from the interior of balloon flower root

A bacterial strain, designated CY22, was isolated from the interior of balloon flower (Platycodon grandiflorum) root in the Republic of Korea. The isolate coproduced an iturin-like antifungal compound and a surfactin-like potent biosurfactant. Analysis of the 16S-rDNA of strain CY22 showed that the isolate was a member of Bacillus. High similarities were observed between strain CY22 and Bacillus sp. TKSP 24, and between strain CY22 and B. subtilis 168. Phylogenetic analysis based on 16S-rDNA sequences showed that strain CY22 was closely related to Bacillus sp. The main whole-cell fatty acids were anteiso-C15:0 (37%), C17:0 (5.1%), and iso-C15:0 (27.7%). DNA G+C content was 54 mol%. Based on phylogenetic inference, phenotypic and chemotaxonomic characteristics, this endophytic strain Bacillus sp. CY22 was assigned to the genus Bacillus.     

Serologic survey for canine distemper and infectious canine hepatitis in wolves in Alaska

Sera from 57 wolves (Canis lupus) in three areas of Alaska were evaluated for evidence of previous exposure to infectious canine hepatitis virus (ICHV) and canine distemper virus (CDV). Fifty-four sera (94.7%) were positive for ICHV exposure and four (7%) were positive for CDV exposure. All four CDV-reacting wolves also had titres to ICHV. The relatively common occurrence of ICHV exposure may be due to the greater resistance of ICHV to chemical and physical agents and its transmissibility via the urine of infected animals. The ICHV titres observed could indicate enzootic pathogenic ICHV, or exposure to the mildly pathogenic vaccine strain of CAV-1 through contact with the urine of domestic dogs. If CAV-1 is the original source of exposure, the titres could represent an ICHV-protected wolf population.     

Benthic ecology of a spring-fed river of interior Alaska

1. A massive aquifer between the Gerstle, Tanana and Delta rivers in interior Alaska receives water from them and from smaller streams that flow from the Granite Mountains in the Alaska Range, Groundwater from the aquifer intersects the surface in a mid-sized (20m³s^?1× 10%) spring-fed stream, Clearwater Creek. 2. Mean annual air temperature is about -2.6°C. However, even in winter when air temperature often reaches —40°C, the stream does not form a complete ice cover. Water temperature ranges from 0 to 7.8°C. Specific conductance and the concentrations of major ions vary little throughout the year, and summed ionic salinity exceeds 250 mg1-^?1. 3. Benthic algal standing crop (as chlorophyll a) was at least an order of magnitude higher than that in a nearby surface-water stream, the upper Chena River, Standing crop peaked in spring and autumn (about 20mgm^?2) and averaged about half this value, although biomass of an early spring bloom of Hydrurus foetid us was underestimated. 4. Algal standing crop was inversely related to the concentrations of inorganic nitrogen and orrhophosphate-phosphorus in the water column. The ratio of total nitrogen to total phosphorus (as mass concentrations) was always about 30. Measurements of primary production made in Clearwater Creek were among the highest reported for streams in subarctic Alaska. 5. Macroinvertebrate diversity in Clearwater Creek was low. Numbers of ‘morpho-species’ in monthly Surber samples (0.09m²) averaged nine, and ranged from three to fourteen. However, benthos and drift densities were similar to those reported from other Alaskan streams. In early spring and autumn, drifting macroinvertebrates were primarily Ephemeroptera, Plecoptera and Trichoptera, but in summer, Diptera dominated the drift. The low diversity of macroinvertebrates is hypothesized to be a consequence of the small annual range in water temperature and the relatively constant discharge of Clearwater Creek.     

Serologic survey for selected microbial pathogens of wolves in Alaska, 1975-1982

Serum samples were collected from 116 wolves which were captured in southcentral Alaska during 1975 through 1982. Antibodies to the following infectious disease agents were found: infectious canine hepatitis virus-72 of 87 (81%), canine parvovirus type 2-0 of 55 (0%) through 1979 and 10 of 32 (31%) after 1979, Francisella tularensis-16 of 67 (25%), canine distemper virus-10 of 83 (12%), Coxiella burnetti-5 of 95 (5%), rabies virus-1 of 88 (1%), Brucella spp.-1 of 67 (1%), Leptospira interrogans-1 of 82 (1%). Apparently rabies, brucellosis, and leptospirosis were rare and had little effect on the wolf population. Conversely, the other five infections were comparatively common and may have had a negative impact on the health of specific individual wolves, but did not appear to influence the health of the population.     

An Outbreak of Trichinosis with Molecular Identification of Trichinella sp. in Vietnam

The 5th outbreak of trichinosis occurred in a mountainous area of North Vietnam in 2012, involving 24 patients among 27 people who consumed raw pork together. Six of these patients visited several hospitals in Hanoi for treatment. Similar clinical symptoms appeared in these patients within 5-8 days after eating infected raw pork, which consisted of fever, muscle pain, difficult moving, edema, difficult swallowing, and difficult breathing. ELISA revealed all (6/6) positive reactions against Trichinella spiralis antigen and all cases showed positive biopsy results for Trichinella sp. larvae in the muscle. The larvae detected in the patients were identified as T. spiralis (Vietnamese strain) by the molecular analysis of the mitochondrial cytochrome c oxidase subunit III (cox3) gene.     

Nitrogen retention in the hyporheic zone of a glacial river in interior Alaska

We examined the hydrologic controls on nitrogen biogeochemistry in the hyporheic zone of the Tanana River, a glacially-fed river, in interior Alaska. We measured hyporheic solute concentrations, gas partial pressures, water table height, and flow rates along subsurface flowpaths on two islands for three summers. Denitrification was quantified using an in situ ¹⁵NO₃⁻ push–pull technique. Hyporheic water level responded rapidly to change in river stage, with the sites flooding periodically in mid−July to early−August. Nitrate concentration was nearly 3-fold greater in river (ca. 100 μg NO₃⁻–N l⁻¹) than hyporheic water (ca. 38 μg NO₃⁻–N l⁻¹), but approximately 60–80% of river nitrate was removed during the first 50 m of hyporheic flowpath. Denitrification during high river stage ranged from 1.9 to 29.4 mg N kg sediment⁻¹ day⁻¹. Hotspots of methane partial pressure, averaging 50,000 ppmv, occurred in densely vegetated sites in conjunction with mean oxygen concentration below 0.5 mgO₂ l⁻¹. Hyporheic flow was an important mechanism of nitrogen supply to microbes and plant roots, transporting on average 0.41 gNO₃⁻–N m⁻² day⁻¹, 0.22 g NH₄⁺–N m⁻² day⁻¹, and 3.6 g DON m⁻² day⁻¹ through surface sediment (top 2 m). Our results suggest that denitrification can be a major sink for river nitrate in boreal forest floodplain soils, particularly at the river-sediment interface. The stability of the river hydrograph and the resulting duration of soil saturation are key factors regulating the redox environment and anaerobic metabolism in the hyporheic zone.     

Molecular identification of Taenia spp. in wolves (Canis lupus), brown bears (Ursus arctos) and cervids from North Europe and Alaska

Taenia tapeworms of Finnish and Swedish wolves (Canis lupus) and Finnish brown bears (Ursus arctos), and muscle cysticerci of Svalbard reindeer (Rangifer tarandus platyrhynchus), Alaskan Grant's caribou (Rangifer tarandus granti) and Alaskan moose (Alces americanus) were identified on the basis of the nucleotide sequence of a 396 bp region of the mitochondrial cytochrome c oxidase subunit 1 gene. Two species were found from wolves: Taenia hydatigena and Taenia krabbei. The cysticerci of reindeer, caribou and one moose also represented T. krabbei. Most of the cysticercal specimens from Alaskan moose, however, belonged to an unknown T. krabbei-like species, which had been reported previously from Eurasian elks (Alces alces) from Finland. Strobilate stages from two bears belonged to this species as well. The present results suggest that this novel Taenia sp. has a Holarctic distribution and uses Alces spp. as intermediate and ursids as final hosts.     

Seroprevalence of Trichinella sp. in Wild Boars (Sus scrofa) from Yanggu-gun,Gangwon-do,Korea

A total 7 outbreaks of trichinellosis have occurred in Korea, mostly as a result of consumption of raw wild boar (Sus scrofa) meat. Since only 1 serological survey on wild boars had yet been performed in Korea, the present study aimed to estimate the prevalence of trichinellosis in wild boars and some species of rodents by artificial digestion and serological examinations in Yanggu-gun, Gangwon-do, the endemic area of trichinellosis. Both the wild boar and rodent muscle samples revealed no Trichinella larvae by direct examination and artificial digestion method. However, serological examinations revealed that 4 wild boar sera samples out of 118 (3.4%) were positive to Trichinella antigen. Although the recovery of Trichinella larvae ended in a failure, it is proved for the first time that the sylvatic cycle of Trichinella has been maintained in wild boars of Gangwon-do, Korea.     

Trichinella spiralis: comparison of stages in host intestine with those of an Arctic Trichinella sp

The intestinal phase of Trichinella spiralis and of Trichinella sp. isolated in the Arctic were compared in experimental animals. Reproductive capacity, pathogenicity, distribution, and persistence of adults in the small intestine, morphological measurements, and release of newborn larvae in vitro were examined. Numerous passages of 40 days each for T. spiralis and the Trichinella sp. isolate in mice did not affect reproductive capacity, distribution of adults in the small intestine, and size of worms. Reproductive capacity index for T. spiralis, I = 151.27 ± 27.30 was significantly higher compared to the Trichinella sp. isolate index, I = 63.46 ± 19.34. The Trichinella sp. isolate was more pathogenic to mice and wild rodents compared to T. spiralis during the intestinal phase. Both parasites were located in the anterior part of the small intestine but the position of T. spiralis adults (P = 17.08) differed from position of the Trichinella sp. isolate adults (P = 23.46) in the small intestine. Intestinal phase of T. spiralis was longer (20 days) compared to the Trichinella sp. isolate (15 days) but sex ratios (:♂) were similar for both parasites. T. spiralis females released significantly higher numbers of larvae in vitro/24 hr compared to the Trichinella sp. isolate. Release of larvae was continuous during the intestinal phase and the average fecundity for T. spiralis was 335 larvae/female and for the Trichinella sp. isolate 114 larvae/female. Adults of T. spiralis and the Trichinella sp. isolate were morphologically indistinguishable and did not differ in size. A comparative index for the intestinal phase is proposed for comparison of any Trichinella spp. isolates and standard T. spiralis.     

Simulation of moss and tree dynamics in the boreal forests of interior Alaska

We used a simulation model of forest dynamics to examine the ecological significance of the complex interactions among site conditions, tree growth, and the development of a thick forest floor moss layer found in many boreal forests. To examine the effect of site conditions on moss growth and forest dynamics, we simulated the dynamics of several different forest sites in the uplands of interior Alaska. Then we used a cold, wet permafrost site to examine the ecological consequences of direct moss and tree interactions. Our analyses revealed a tightly coupled system in which forest succession was highly sensitive to the interactions among site conditions, mosses, and trees. The effect of mosses on the soil thermal regime was a particularly important feedback. Direct interactions between mosses and trees that affected the development of a thick forest floor layer were also important. In particular, shading of moss by trees, reduced tree regeneration on moss-covered soils, and reduced moss growth with open forest canopies were also important determinants of forest succession. These complex feedbacks ensure that an ecosystem approach is needed to understand the ecology of boreal forests.     

Infectivity of Trichinella sp. isolated from Crocodylus niloticus to the indigenous Zimbabwean pig (Mukota).

An experimental infection of the indigenous Zimbabwean pig (Mukota) with a Trichinella sp. derived from crocodile (Crocodylus niloticus) was performed. The same larval isolates of Trichinella were infected to rats as a control. The muscles of both pigs and rats were found to be heavily infected with the first-stage larvae. The present study constitutes the first report of a successful experimental infection of the pig with Trichinella sp. originating from crocodile.     

Succession-driven changes in soil respiration following fire in black spruce stands of interior Alaska

Boreal forests are highly susceptible to wildfire, and post-fire changes in soil temperature and moisture have the potential to transform large areas of the landscape from a net sink to a net source of carbon (C). Understanding the ecological controls that regulate these disturbance effects is critical to developing models of ecosystem response to changes in fire frequency and severity. This paper combines laboratory and field measurements along a chronosequence of burned black spruce stands into regression analyses and models that assess relationships between moss succession, soil microclimate, decomposition, and C source-sink dynamics. Results indicate that post-fire changes in temperature and substrate quality increased decomposition in humic materials by a factor of 3.0 to 4.0 in the first 7 years after fire. Bryophyte species exhibited a distinct successional pattern in the first five decades after fire that corresponded to decreased soil temperature and increased C accumulation in organic soils. Potential rates of C exchange in mosses were greatest in early successional species and declined as the stand matured. Residual sources of CO₂ (those not attributed to moss respiration or humic decomposition) increased as a function of stand age, reflecting increased contributions from roots as the stand recovered from disturbance. Together, the field measurements, laboratory experiments, and models provide strong evidence that interactions between moss and plant succession, soil temperature, and soil moisture largely regulate C source-sink dynamics from black spruce systems in the first century following fire disturbance.     

Serologic survey for selected disease agents in wolves (Canis lupus) from Alaska and the Yukon Territory, 1984-2000

Wolves (Canis lupus) were captured in several geographic areas of Alaska (USA) and the Yukon Territory (Canada) during 1984-2000. Blood was collected from 1,122 animals. Sera were tested for antibodies against infectious canine hepatitis virus (ICH), canine distemper virus (CDV), canine parvovirus (CPV), Francisella tularensis, and serovars of Leptospira interrogans. Antibody prevalence for ICH was >84% for all areas. Area-specific prevalences of antibodies ranged from 12% to 70% for CPV, from 0% to 41% for CDV, and from 4% to 21% for F. tularensis. There was no evidence of CDV exposure at the two southernmost locations in Alaska. Prevalence of antibodies for ICH increased slightly during the 16-yr course of the survey. There was essentially no evidence of exposure to L. interrogans. Prevalences of antibodies for both CPV and CDV were age-specific, with higher values in the adult cohort compared with the pup cohort. There were no sex-specific differences in prevalence of antibodies for any of the five disease agents.