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At least 721 records · Page 40Linked to original sources

Parasites of the mink frog (Rana septentrionalis) from Minnesota, U.S.A.

Twenty-two mink frogs, Rana septentrionalis , collected from two locations in Minnesota, United States, were examined for helminth and protozoan blood parasites in July 1999. A total of 16 parasite taxa were recovered including 5 larval digenean trematodes, 7 adult digenean trematodes, 3 nematodes, and 1 Trypanosoma species. Infracommunities were dominated by the digeneans in terms of richness and abundance. In particular, echinostomatid metacercariae in the kidneys of frogs were the most common parasites found, infecting 100% of the frogs and consisting of about 90% of all helminth individuals recovered. Gorgodera amplicava , Gorgoderina multilobata , Haematoloechus parviplexus , Haematoloechus breviplexus , Cosmocercoides dukae , and Oswaldocruzia pipiens represent new host records. The survey presented here represents the second known helminth survey of mink frogs conducted in North America. A summary of metazoan parasites reported from mink frogs is included.

Minnesota↗

Are prey remains accurate indicators of chick diet? A comparison of diet quantification techniques for Black Oystercatchers

The quantification of prey remains is a common method for estimating the diet of a variety of birds. However, these estimates may be subject to biases based on prey body type, nesting habitat, and collection date. To better understand biases and limitations associated with this method, we compared it with two others commonly used to characterize diet: direct observation of parents feeding young and diet reconstruction by stable isotope analysis. In 2013-14, we monitored the diet of 20 Black Oystercatcher broods in south-central Alaska using all three methods, having collected 2126 prey remains, observed 1979 prey items fed to chicks, and obtained stable isotopes values of 39 blood samples from 22 chicks. Direct observations and stable isotope techniques similarly characterized diet composition but these approaches yielded different results from those obtained using prey remains. Soft-bodied prey, such as worms, were not detected in prey remains, and filter-feeders were under-represented. For example, mussels and barnacles, which have flesh that can be removed without having to detach the shell from the substrate, were underestimated using prey remains (mussels: 33% for prey remains vs. 44%, 43% for observations and stable isotopes, respectively; barnacles: 2% vs. 9%, 8%, respectively). On rocky islands, where chicks are confined to a small area around the nest, there were significantly greater quantities of prey remains constituting different diets than on gravel beaches, where chicks leave the nest site within days of hatching. For researchers using prey remains to monitor diet, we suggest that they combine this method with direct observations or stable isotope analysis to understand what prey items may be missed or under-represented.

Alaska↗

Biomarkers of exposure and effects of environmental contaminants on swallows nesting along the Rio Grande, Texas, USA

We collected adult cave swallows (Petrochelidon fulva) and cliff swallows (P. pyrrhonota) during the breeding seasons in 1999 and 2000 from eight locations along the Rio Grande from Brownsville to El Paso (unless otherwise specified, all locations are Texas, USA) and an out-of-basin reference location. Body mass, spleen mass, hepatosomatic index (HSI), gonadosomatic index (GSI), thyroxine (T4) in plasma, DNA damage measured as the half-peak coefficient of variation of DNA content (HPCV) in blood cells, as well as acetylcholinesterase and butyrylcholinesterase in brain were compared with concentrations of organochlorines, metals, and metalloids in carcasses to determine potential effects of contaminants on swallows during the breeding season. Concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p???-DDE) were significantly greater in swallows from El Paso than in those from most locations, except for Pharr and Llano Grande. All swallows from these three locations had p,p???-DDE concentrations of 3 ??g/g wet weight or greater. Swallows from El Paso either had or shared the highest concentrations of p,p???-DDE, polychlorinated biphenyls, and 13 inorganic elements. Swallows from El Paso exhibited greater spleen mass and HPCV values as well as lower T4 values compared with those from other locations. Thyroxine was a potential biomarker of contaminant exposure in swallows of the Rio Grande, because it was negatively correlated with p,p???-DDE and Se. Spleen mass was positively correlated with selenium and HSI and negatively correlated with body mass, GSI, Mn, and Ni. Overall, the present study suggests that insectivorous birds living in areas of high agricultural and industrial activity along the Rio Grande bioaccumulate environmental contaminants. These contaminants, particularly p,p???-DDE, may be among multiple factors that impact endocrine and hematopoietic function in Rio Grande swallows. ?? 2006 SETAC.

Environmental Toxicology and Chemistry↗

DNA damage and external lesions in brown bullheads (Ameiurus nebulosus) from contaminated habitats

The Comet assay was used to compare levels of DNA damage in brown bullheads ( Ameiurus nebulosus ) collected from three known contaminated locations, the Cuyahoga River (OH, USA), Ashtabula River (OH, USA; both tributaries to Lake Erie, USA), and Ashumet Pond (Cape Cod, MA, USA), with brown bullheads collected from three paired reference sites, Old Woman Creek (OH, USA), Conneaut River (OH, USA; both tributaries to Lake Erie), and Great Herring Pond (mainland MA, USA), respectively. Blood was sampled from each fish, and the Comet assay was conducted on erythrocytes. The assay results demonstrate that fish from the three contaminated sites each suffered higher DNA damage compared with fish from their respective reference sites. The results also show that the genetic damage was associated with the occurrence of external lesions and deformities in fish. The Comet assay is sufficiently sensitive to detect exposure of natural fish populations to environmental levels of genotoxic contaminants.

Environmental Toxicology and Chemistry↗

Distribution and accumulation of mercury in tissues of captive-reared common loon (Gavia immer) chicks

We determined the distribution and accumulation of Hg in tissues of common loon (Gavia immer) chicks maintained for up to 15 weeks on either a control diet with no added methylmercury chloride (MeHgCl) or one containing either 0.4 or 1.2 ??g Hg (as MeHgCl)/g wet-weight food. Total Hg and MeHg tissue concentrations were strongly positively correlated (r2 > 0.95) with the amount of Hg delivered to individual chicks throughout the course of the experiment. The pattern of differential Hg concentration in internal tissues was consistent within each treatment: Liver > kidney > muscle > carcass > brain. Feather Hg concentrations were consistently higher than those of internal tissues and represented an important route of Hg elimination. Feather mass accounted for 4.3% ?? 0.1% (average ?? standard error) of body mass, yet 27.3% ?? 2.6% of total Hg intake was excreted into feathers. Our calculations indicate that 26.7% ?? 4.9% of ingested Hg was not accounted for and, thus, either was never absorbed or was absorbed and subsequently eliminated in feces. With the additional excretion into feathers, 54% of ingested Hg was excreted. Demethylation was evident in the liver at all treatment levels and in the kidneys of chicks dosed at 1.2 ??g Hg/g. Mercury concentrations were strongly positively correlated (r2 ??? 0.95) among internal tissues and with blood Hg concentration. Mercury concentrations of secondary feathers were moderately correlated (r2 = 0.82-0.93) with internal tissues. We supply regression models that may be used to provide perspective and a useful means of interpreting the variety of measures of Hg exposure reported in the literature. ?? 2007 SETAC.

Environmental Toxicology and Chemistry↗

Effects of methylmercury exposure on the immune function of juvenile common loons (Gavia immer)

We conducted a dose-response laboratory study to quantify the level of exposure to dietary Hg, delivered as methylmercury chloride (CH3HgCl), that is associated with suppressed immune function in captive-reared common loon (Gavia immer) chicks. We used the phytohemagglutinin (PHA) skin test to assess T-lymphocyte function and the sheep red blood cell (SRBC) hemagglutination test to measure antibody-mediated immunity. The PHA stimulation index among chicks receiving dietary Hg treatment did not differ significantly from those of chicks on the control diet (p = 0.15). Total antibody (immunoglobulin [Ig] M [primary antibody] + IgG [secondary response]) production to the SRBC antigen in chicks treated with dietary methylmercury (MeHg), however, was suppressed (p = 0.04) relative to chicks on control diets. Analysis indicated suppression of total Ig production (p = 0.025 with comparisonwise ?? level = 0.017) between control and 0.4 ??g Hg/g wet food intake treatment groups. Furthermore, the control group exhibited a higher degree of variability in antibody response compared to the Hg groups, suggesting that in addition to reducing the mean response, Hg treatment reduced the normal variation attributable to other biological factors. We observed bursal lymphoid depletion in chicks receiving the 1.2 ??g Hg/g treatment (p = 0.017) and a marginally significant effect (p = 0.025) in chicks receiving the 0.4 ??g Hg/g diet. These findings suggest that common loon chick immune systems may be compromised at an ecologically relevant dietary exposure concentration (0.4 ??g Hg/g wet wt food intake). We also found that chicks hatched from eggs collected from low-pH lakes exhibited higher levels of lymphoid depletion in bursa tissue relative to chicks hatched from eggs collected from neutral-pH lakes. ?? 2007 SETAC.

Environmental Toxicology and Chemistry↗

Utilization of protein expression profiles as indicators of environmental impairment of smallmouth bass (Micropterus dolomieu) from the Shenandoah River, Virginia, USA

The Shenandoah River (VA, USA), the largest tributary of the Potomac River (MD, USA) and an important source of drinking water, has been the site of extensive fish kills since 2004. Previous investigations indicate environmental stressors may be adversely modulating the immune system of smallmouth bass ( Micropterus dolomieu ) and other species. Anterior kidney (AK) tissue, the major site of blood cell production in fish, was collected from smallmouth bass at three sites along the Shenandoah River. The tissue was divided for immune function and proteomics analyses. Bactericidal activity and respiratory burst were significantly different between North Fork and mainstem Shenandoah River smallmouth bass, whereas South Fork AK tissue did not significantly differ in either of these measures compared with the other sites. Cytotoxic cell activity was highest among South Fork and lowest among North Fork AK leukocytes. The composite two‐dimension gels of the North Fork and mainstem smallmouth bass AK tissues contained 584 and 591 spots, respectively. South Fork smallmouth bass AK expressed only 335 proteins. Nineteen of 50 proteins analyzed by matrix‐assisted laser desorption ionization‐time of flight were successfully identified. Three of the four identified proteins with increased expression in South Fork AK tissue were involved in metabolism. Seven proteins exclusive to mainstem and North Fork smallmouth bass AK and expressed at comparable abundances serve immune and stress response functions. The proteomics data indicate these fish differ in metabolic capacity of AK tissue and in the ability to produce functional leukocytes. The variable responses of the immune function assays further indicate disruption to the immune system. Our results allow us to hypothesize underlying physiological changes that may relate to fish kills and suggest relevant contaminants known to produce similar physiological disruption.

Virginia↗

Apparent tolerance of turkey vultures (Cathartes aura) to the non-steroidal anti-inflammatory drug diclofenac

The nonsteroidal anti‐inflammatory drug diclofenac is extremely toxic to Old World Gyps vultures (median lethal dose ∼0.1–0.2 mg/kg), evoking visceral gout, renal necrosis, and mortality within a few days of exposure. Unintentional secondary poisoning of vultures that fed upon carcasses of diclofenac‐treated livestock decimated populations in the Indian subcontinent. Because of the widespread use of diclofenac and other cyclooxygenase‐2 inhibiting drugs, a toxicological study was undertaken in turkey vultures ( Cathartes aura ) as an initial step in examining sensitivity of New World scavenging birds. Two trials were conducted entailing oral gavage of diclofenac at doses ranging from 0.08 to 25 mg/kg body weight. Birds were observed for 7 d, blood samples were collected for plasma chemistry (predose and 12, 24, and 48 h and 7 d postdose), and select individuals were necropsied. Diclofenac failed to evoke overt signs of toxicity, visceral gout, renal necrosis, or elevate plasma uric acid at concentrations greater than 100 times the estimated median lethal dose reported for Gyps vultures. For turkey vultures receiving 8 or 25 mg/kg, the plasma half‐life of diclofenac was estimated to be 6 h, and it was apparently cleared after several days as no residues were detectable in liver or kidney at necropsy. Differential sensitivity among avian species is a hallmark of cyclooxygenase‐2 inhibitors, and despite the tolerance of turkey vultures to diclofenac, additional studies in related scavenging species seem warranted.

Environmental Toxicology and Chemistry↗

Sero-epidemiology of Highly Pathogenic Avian Influenza viruses among wild birds in subarctic intercontinental transition zones

Background: The geographic expansion and evolution of A/Goose/Guangdong/1/1996(H5N1) (Gs/GD) lineage H5Nx highly pathogenic avian influenza (HPAI) viruses since 1996 have raised awareness of enzootic circulation among migratory birds and the potential for intercontinental transport and spread. Recent Pacific- and Atlantic-route introductions of HPAI to North America were facilitated by avian migration through subarctic zones, specifically Alaska and Iceland. This study aimed to identify recent historical patterns of exposure to HPAI viruses among birds within and migrating through both regions and evaluate how geographic, demographic, and taxonomic differences contribute to exposure risk at two intercontinental staging locations. Methods: During 2010-2019, blood samples were obtained from captured wild migratory seabirds and waterfowl in Alaska and Iceland. All live birds were released following completion of sampling. Sampling date, species, sampling location, and age class was documented for each bird, and sex was documented when possible. Lentiviral pseudoviruses that express the influenza hemagglutinin surface glycoprotein for H5Nx HPAI and H5 low-pathogenicity avian influenza (LPAI) were constructed for use in serological assays to screen for and quantify titers of antibodies against the latter viruses. Data were analyzed to compare (a) categorical baseline ecological traits between Iceland and Alaska, and (b) ecological traits between birds identified to be seropositive and suggestive/seronegative/fully cross-reactive birds to H5Nx HPAI in Iceland and Alaska. Factors associated with seroreactivity to H5Nx HPAI and H5 LPAI were assessed. Results: The seroprevalence of HPAI among birds in both locations was 7.3% (112/1526). Findings reveal variability in seroprevalence by year, higher rates of exposure to H5 LPAI than H5Nx HPAI overall, and significantly more seropositive and suggestive exposure of birds to H5Nx HPAI in Alaska as compared to Iceland. Geographic, demographic, and taxonomic differences contribute to exposure risk between Alaska and Iceland. Most tested birds were immuno-naïve to HPAI in both locations, which indicates many migratory birds in the subarctic are susceptible to HPAI infection, demonstrating substantial risk for intercontinental transmission between Asia, Europe, and North America. Conclusions: Our findings provide further justification for increased viral and serosurveillance in Alaska and Iceland to monitor subarctic movements of migratory birds and intercontinental transmission dynamics of currently circulating and new strains of HPAI globally.

Research Square↗

Pesticide residues in the ecosystem

Pesticide residues have become a component of nearly all living organisms. Nearly all California birds and fish collected in a 1963 pesticide survey contained residues. Discovery of DDT and metabolites in Antarctic animals in 1964 pushed the distribution of pesticides to the remotest portions of the globe. Exchange of pesticides in the aquatic world progresses rapidly, even in the quiet waters of a pond. Any segment of the ecosystem–marshland, pond, forest, or field–receives pesticides of varied amounts and kinds at irregular and unknown intervals. Phytoplankton communities are an important food base in aquatic environments whose productivity can be affected by rather small exposure to pesticides. Degradation and loss of chlorinated hydrocarbon pesticides from the ecosystem has been shown to proceed slowly. Pesticide-tolerant or resistant populations of fish and possibly other cold-blooded vertebrates have been shown to exist in areas of the south long subjected to pesticide treatments.

Book chapter↗

Low genotyping error rates and noninvasive sampling in Bighorn Sheep

Noninvasive DNA sampling allows studies of natural populations without disturbing the target animals. Unfortunately, high genotyping error rates often make noninvasive studies difficult. We report low error rates (0.0–7.5%/locus) when genotyping 18 microsatellite loci in only 4 multiplex polymerase chain reaction amplifications using fecal DNA from bighorn sheep ( Ovis canadensis ). The average locus-specific error rates varied significantly between the 2 populations (0.13% vs. 1.6%; P < 0.001), as did multi-locus genotype error rates (2.3% vs. 14.1%; P < 0.007). This illustrates the importance of quantifying error rates in each study population (and for each season and sample preservation method) before initiating a noninvasive study. Our error rates are among the lowest reported for fecal samples collected noninvasively in the field. This and other recent studies suggest that noninvasive fecal samples can be used in species with pellet-form feces for nearly any study (e.g., of population structure, gene flow, dispersal, parentage, and even genome-wide studies to detect local adaptation) that previously required high-quality blood or tissue samples.

Montana↗

Elk calf survival and mortality following wolf restoration to Yellowstone National Park

We conducted a 3‐year study (May 2003–Apr 2006) of mortality of northern Yellowstone elk ( Cervus elaphus ) calves to determine the cause for the recruitment decline (i.e., 33 calves to 13 calves/100 adult F) following the restoration of wolves ( Canis lupus ). We captured, fit with radiotransmitters, and evaluated blood characteristics and disease antibody seroprevalence in 151 calves ≤6 days old (68M:83F). Concentrations (x̄, SE) of potential condition indicators were as follows: thyroxine (T4; 13.8 μg/dL, 0.43), serum urea nitrogen (SUN; 17.4 mg/dL, 0.57), γ‐glutamyltransferase (GGT; 66.4 IU/L, 4.36), gamma globulins (GG; 1.5 g/dL, 0.07), and insulin‐like growth factor‐1 (IGF‐1; 253.6 ng/mL, 9.59). Seroprevalences were as follows: brucellosis ( Brucella abortus ; 3%), bovine‐respiratory syncytial virus (3%), bovine‐viral‐diarrhea virus type 1 (25%), infectious‐bovine rhinotracheitis (58%), and bovine parainfluenza‐3 (32%). Serum urea nitrogen, GGT, GG, and IGF‐1 varied with year; T4, SUN, and GG varied with age ( P ≤ 0.01); and SUN varied by capture area ( P = 0.02). Annual survival was 0.22 (SE = 0.035, n = 149) and varied by calving area but not year. Neonates captured in the Stephens Creek/Mammoth area of Yellowstone National Park, USA, had annual survival rates >3× higher (0.54) than those captured in the Lamar Valley area (0.17), likely due to the higher predator density in Lamar Valley. Summer survival (20 weeks after radiotagging) was 0.29 (SE = 0.05, n = 116), and calving area, absolute deviation from median birth date, and GG were important predictors of summer survival. Survival during winter (Nov‐Apr) was 0.90 (SE= 0.05, n = 42), and it did not vary by calving area or year. Sixty‐nine percent ( n = 104) of calves died within the first year of life, 24% ( n = 36) survived their first year, and 7% ( n = 11) had unknown fates. Grizzly bears ( Ursus arctos ) and black bears ( Ursus americanus ) accounted for 58–60% ( n = 60–62) of deaths, and wolves accounted for 14–17% ( n = 15–18). Summer predation (95% of summer deaths) increased, and winter malnutrition (0% of winter deaths) decreased, compared with a similar study during 1987–1990 (72% and 58%, respectively). Physiological factors (e.g., low levels of GG) may predispose calves to predation. Also, the increase in bear numbers since wolf restoration and spatial components finer than the northern range should be considered when trying to determine the causes of the northern Yellowstone elk decline. This is the first study to document the predation impacts from reintroduced wolves on elk calf mortality in an ecosystem already containing established populations of 4 other major predators (i.e., grizzly and black bears, cougars [ Puma concolor ], and coyotes [ Canis latrans ]). The results are relevant to resource managers of the Yellowstone ecosystem in understanding the dynamics of the elk population, in providing harvest quota recommendations for local elk hunts to the Montana Department of Fish, Wildlife and Parks, the United States Fish and Wildlife Service regarding wolf and grizzly bear recovery, and to all areas worldwide where predators are increasing, by providing managers with information about potential carnivore impacts on elk populations.

Idaho, Montana, Wyoming↗

Avian cholera and organochlorine residues in an American oystercatcher

Pasteurella multocida , the causative bacterium of avian cholera, was isolated from cultures of the liver and heart blood of a female, adult American oystercatcher ( Haematopus palliatus ) found dead on the Cape Romain National Wildlife Refuge, South Carolina, in May 1973. This is apparently the first record of avian cholera in the oystercatcher. Low levels of DDE were identified in tissues of the oystercatcher.

South Carolina↗

Lead concentrations and reproduction in highway-nesting barn swallows

Swallows (Hirundo rustica) collected within the right-of-way of a major Maryland highway were greater than those found in Barn Swallows nesting within a rural area. Lead concentrations in the feathers of adults from the highway colony were also greater than Lead concentrations in the carcasses and stomach contents of adult and nestling Barn those of rural adults, but concentrations in the feathers of nestlings from the two locations were similar. Activity of u-aminolevulinic acid dehydratase in red blood cells was lower in highway-nesting adults and their young than in their rural counterparts, although hemoglobin concentrations and hematocrits did not differ. The number of eggs, nestlings, and body weights of the latter at 16-18 days of age were similar in the two colonies, as were body weights of adults from the two areas. These results suggest that contamination of roadside habitats by lead from automotive emissions does not pose a serious hazard to birds that are aerial feeders.

Condor↗

Haemoproteus iwa n. sp. in great frigatebirds (Fregata minor [Gmelin]) from Hawaii: Parasite morphology and prevalence

We describe a new species of Haemoproteus Kruse, 1890 from great frigatebirds ( Fregata minor [Gmelin]) captured on Tern Island-French Frigate Shoals and Laysan Island in Hawaii. Parasite prevalence on Laysan Island (35%) was not significantly different than that of Tern Island (36%). On Laysan, prevalence was highest in juveniles (52%), followed by adult males (29%) and adult females (19%). Prevalence on Tern was 36% both for adult females and juveniles, and 28% for adult males. Parasitemia was low (mean < 2 parasites/10,000 red blood cell). Parasitized red cells had significantly greater areas than unparasitized cells. We named this parasite Haemoproteus iwa after the Hawaiian name for frigatebirds (iwa). This is the first documentation of a hemoparasite from tropical pelagic seabirds in Hawaii and the first description of an endemic hemoparasite in the archipelago.

Hawai'i↗

Adverse effects on birds of Phosphamidon applied to a Montana forest

A field trial of Phosphamidon applied by aircraft in Montana against spruce budworm ( Choristoneura fumiferana ) had immediate adverse effects on birds. A 5,000-acre block of forested land was sprayed at the rate of 1 pound per acre. Some birds, including blue grouse ( Dendragapus obscurus ), were killed by the insecticide. Bird activity on the sprayed plot dropped to about one-quarter of the prespray level of activity while it increased on an unsprayed plot. Two sick blue grouse were caught by hand and held in captivity; one died and the other recovered. Analysis of grouse blood samples showed a marked inhibition of cholinesterase activity in the sick birds, followed by return of cholinesterase to normal in the surviving bird.

Montana↗

Erythrocyte δ-Aminolevulinic Acid Dehydratase Activity in Mallard Ducks: Duration of Inhibition after Lead Shot Dosage

Inhibition of a lead-specific blood enzyme, 8-aminolevulinic acid dehydratase (ALAD), has been utilized to indicate the incidence and degree of lead contamination in canvasback ducks ( Aythya valisineria ) (Dieter et al. 1976). This variable was found to be more sensitive to lead than previous tests that have been employed with waterfowl (Locke et al. 1966, 1967), and has proved to be completely reliable (Finley et al. 1976a,b). However, it is not yet known how long ALAD enzyme inhibition persists after a source of high head contamination is removed. The duration of inhibition is critical because too brief a response would result in underestimating the extent of lead contamination in a given year's survey. Moreover, the ALAD enzyme bioassay can be used to identify ducks that have ingested lead shot, as well as those that have ingested low levels of lead in their forage, and this information used to help remove the source of the environmental contamination.

Maryland↗

Microbial infections in a declining wild turkey population in Texas

A survey was conducted at 5 locations in Texas for avian pathogens that might adversely affect wild turkey ( Meleagris gallopavo ) productivity and survival. At 1 site, the Rob and Bessie Welder Wildlife Refuge (WWR), turkeys have declined precipitously in recent years. During the winters of 1983-85, 442 wild turkeys were caught with cannon and drop nets, 161 of these on WWR. Blood samples were drawn for serologic evaluation, and cloacal and tracheal swabs were collected for isolation attempts. Salmonella spp. bacteria, Newcastle disease virus (NDV), and avian influenza virus (AIV) were not detected in any samples tested. Serologic tests for antibodies to NDV and AIV also were negative. Many mycoplasma isolates were recovered from turkeys from every location. Characterization of these isolates indicated that several species were present. None were species typically associated with mycoplasmosis in domestic turkeys, such as Mycoplasma gallisepticum (MG), M. meleagridis (MM), or M. synoviae (MS), although antibodies to these pathogens were detected in turkeys at every location sampled. There was no evidence to link any of these disease causing agents to the decline observed in the population of wild turkeys on the WWR.

Texas↗