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PubMed2004

Phylogenetic relationships among virulent Newcastle disease virus isolates from the 2002-2003 outbreak in California and other recent outbreaks in North America.

Isolates from the 2002-2003 virulent Newcastle disease virus (v-NDV) outbreak in southern California, Nevada, Arizona, and Texas in the United States were compared to each other along with recent v-NDV isolates from Mexico and Central America and reference avian paramyxovirus type 1 strains. Nucleotide sequencing and phylogenetic analyses were conducted on a 1,195-base genomic segment composing the 3' region of the matrix (M) protein gene and a 5' portion of the fusion (F) protein gene including the M-F intergenic region. This encompasses coding sequences for the nuclear localization signal of the M protein and the F protein cleavage activation site. A dibasic amino acid motif was present at the predicted F protein cleavage activation site in all v-NDVs, including the California 2002-2003, Arizona, Nevada, Texas, Mexico, and Central America isolates. Phylogenetic analyses demonstrated that the California 2002-2003, Arizona, Nevada, and Texas viruses were most closely related to isolates from Mexico and Central America. An isolate from Texas obtained during 2003 appeared to represent a separate introduction of v-NDV into the United States, as this virus was even more closely related to the Mexico 2000 isolates than the California, Arizona, and Nevada viruses. The close phylogenetic relationship between the recent 2002-2003 U.S. v-NDV isolates and those viruses from countries geographically close to the United States warrants continued surveillance of commercial and noncommercial poultry for early detection of highly virulent NDV.

Amino Acid Motifs↗

PubMed1994

Current status of sweat testing in North America. Results of the College of American Pathologists needs assessment survey.

The College of American Pathologists surveyed 5096 laboratories for information concerning collection and analytic methodologies used in the performance of the sweat test. The test measures the concentration of electrolytes in sweat and is an essential criterion for the diagnosis of cystic fibrosis. An 83% response rate was achieved on the needs assessment survey, representing the first large-scale, national study of sweat testing practices. Nineteen percent of the respondents perform sweat testing in their laboratory, and the majority of the respondents analyze the sweat for chloride concentration. Fifty-nine percent of the laboratories performing sweat testing indicated an interest in participating in proficiency testing for sweat analysis. The information gathered from the needs assessment survey will be used to develop a comprehensive proficiency testing program to provide feedback and education to laboratories performing this critical diagnostic test.

Chemistry, Clinical↗

PubMed1993

Incidence, characteristics, and outcome of spinal cord injury at trauma centers in North America.

Acute spinal cord injury occurred in 2.6% of the 114,510 patients entered into the Major Trauma Outcome Study from 1982 to 1989. The most common causes of spinal cord injury were motor vehicle accidents (40%), falls (20%), and gunshot wounds (13.6%). Almost 80% of patients with spinal cord injury had multiple injuries. Cervical cord injury was seen in 65% of patients with isolated spinal cord injury, but in only 52% of patients with multiple injuries. The hospital mortality rate was 17%, with patients with multiple injuries having a significantly higher mortality rate than patients with isolated spinal cord injury (19.8% vs 6.9%). The TRISS method overpredicted the mortality rate among patients with multiple injuries (450 vs 379), but not among those with isolated injury. A program for better national surveillance and prevention of spinal cord injury is warranted.

Accidents, Traffic↗

PubMed1982

Autocidal control of screwworms in North America.

The larva of the blowfly Cochliomyia hominivorax, also known as the screwworm, eats the living flesh of cattle and sheep and other warm-blooded animals. A program to eradicate the screwworm in the United States was initiated in the 1950's. The program was very effective until 1968, but severe screwworm outbreaks occurred in 1972 to 1976 and in 1978. Although the program has again been effective since 1979, the possibility of outbreaks recurring in the future has highlighted the need for a broader understanding of the pest. Studies of screwworm populations in the United Stated and Mexico indicate that much of the genetic diversity of this insect is distributed among sympatric non-interbreeding populations. A new approach may be required to retain the effectiveness of the control program and to prevent a serious outbreak from threatening the economic viability of the U.S. livestock industry.

Animals↗

PubMed2005

Legal liabilities in research: early lessons from North America.

The legal risks associated with health research involving human subjects have been highlighted recently by a number of lawsuits launched against those involved in conducting and evaluating the research. Some of these cases have been fully addressed by the legal system, resulting in judgments that provide some guidance. The vast majority of cases have either settled before going to trial, or have not yet been addressed by the courts, leaving us to wonder what might have been and what guidance future cases may bring. What is striking about the lawsuits that have been commenced is the broad range of individuals/institutions that are named as defendants and the broad range of allegations that are made. The research community should take this early experience as a warning and should reflect carefully on practices where research involving human subjects is concerned.

Clinical Trials as Topic↗

PubMed2006

Cumulative effects of climate warming and other human activities on freshwaters of Arctic and subarctic North America.

Despite their generally isolated geographic locations, the freshwaters of the north are subjected to a wide spectrum of environmental stressors. High-latitude regions are especially sensitive to the effects of recent climatic warming, which have already resulted in marked regime shifts in the biological communities of many Arctic lakes and ponds. Important drivers of these limnological changes have included changes in the amount and duration of snow and ice cover, and, for rivers and lakes in their deltas, the frequency and extent of spring floods. Other important climate-related shifts include alterations in evaporation and precipitation ratios, marked changes in the quality and quantity of lake and river water inflows due to accelerated glacier and permafrost melting, and declining percentages of precipitation that falls as snow. The depletion of stratospheric ozone over the north, together with the clarity of many Arctic lakes, renders them especially susceptible to damage from ultraviolet radiation. In addition, the long-range atmospheric transport of pollutants, coupled with the focusing effects of contaminant transport from biological vectors to some local ecosystems (e.g., salmon nursery lakes, ponds draining seabird colonies) and biomagnification in long food chains, have led to elevated concentrations of many persistent organic pollutants (e.g., insecticides, which have never been used in Arctic regions) and other pollutants (e.g., mercury). Rapid development of gas and oil pipelines, mining for diamonds and metals, increases in human populations, and the development of all-season roads, seaports, and hydroelectric dams will stress northern aquatic ecosystems. The cumulative effects of these stresses will be far more serious than those caused by changing climate alone.

Animals↗

PubMed1988

Metazoan parasites of Himantopus mexicanus Muller (Aves) from southwestern Texas, with a checklist of helminth parasites from North America.

Nineteen species of helminths were recovered from 34 of 35 black-necked stilts, Himantopus mexicanus Muller, collected from the Fort Bliss ponds, El Paso County, Texas. New host records are marked with an. The species identified were: Acoleus vaginatus, Davainea himantopodis, Diplophallus polymorphus, Eurycestus avoceti, Hymenolepis himantopodis, Hymenolepis sp. 1, Infula macrophallus, Coacitrema michiganensis, Cyclocoelum lanceolatum, Notocotylus sp., Parastrigea mexicanus, Tanaisia fedtschenkoi, Capillaria sp., C. anatis, C. contorta, C. mergi, Chevreuxia americana, Eustronglydes mergorum, and Splendidofilaria sp. Six species of mallophagan lice and 1 species of nasal mite, Rhinonyssus himantopus, were recovered. Helminths showed little concentration for dominance (0.09), were not very evenly distributed (0.49 +/- 0.08) nor very diverse (0.73 +/- 0.14), and most species were highly aggregated. The helminth community consisted of an unusually large number of core species (10). Three large species of tapeworms exhibited mostly paired infections, were mutually exclusive, and were negatively associated (-1).

Animals↗

PubMed2006

Birds and influenza H5NI virus movement to and within North America.

Highly pathogenic avian influenza (HPAI) H5N1 expanded considerably during 2005 and early 2006 in both avian host species and geographic distribution. Domestic waterfowl and migratory birds are reservoirs, but lethality of this subtype appeared to initially limit migrant effectiveness as introductory hosts. This situation may have changed, as HPAI H5N1 has recently expanded across Eurasia and into Europe and Africa. Birds could introduce HPAI H5N1 to the Western Hemisphere through migration, vagrancy, and importation by people. Vagrants and migratory birds are not likely interhemispheric introductory hosts; import of infected domestic or pet birds is more probable. If reassortment or mutation were to produce a virus adapted for rapid transmission among humans, birds would be unlikely introductory hosts because of differences in viral transmission mechanisms among major host groups (i.e., gastrointestinal for birds, respiratory for humans). Another possible result of reassortment would be a less lethal form of avian influenza, more readily spread by birds.

Animal Migration↗

PubMed2005

Three multiplex assays for detection of Borrelia burgdorferi sensu lato and Borrelia miyamotoi sensu lato in field-collected Ixodes nymphs in North America.

Two hundred fifty New Jersey field-collected Ixodes scapularis Say ticks and 17 Colorado Ixodes spinipalpis Hadwen & Nuttall ticks were tested using three separate multiplex real-time polymerase chain reaction (PCR) assays. One assay targets the rrs-rrlA IGS region of Borrelia spp. to detect Borrelia burgdorferi sensu lato (s.l.) and Borrelia miyamotoi s.l. The second assay targets the ospA region of B. burgdorferi s.l. to detect B. burgdorferi sensu stricto (s.s.), Borrelia bissettii, and Borrelia andersonii. The final assay targets the glpQ region of B. miyamotoi s.l. to differentiate B. miyamotoi LB-2001 and Borrelia lonestari. A testing scheme combining these tests yielded 18% of tested I. scapularis ticks surveyed from New Jersey positive for B. burgdorferi s.s., 3.2% I. scapularis ticks positive for B. miyamotoi LB-2001, and 41.2% I. spinipalpis ticks positive for B. bissettii surveyed from Colorado.

Animals↗

PubMed2003

Tracing the geographical origin of Megastigmus transvaalensis (Hymenoptera: Torymidae): an African wasp feeding on a South American plant in North America.

Determining the geographical origin of an introduced organism can be critical to understanding or managing a non-native species, but is often difficult when the organism is small or inconspicuous. We used a phylogeographical approach to identify the region of endemism and determine the geographical origin of world populations of the seed-feeding wasp Megastigmus transvaalensis (Hussey). This wasp feeds on African Rhus species and South American Schinus species in various locations around the world. Because it is present both in Africa and in South America, it is unclear whether the wasp was originally an African Rhus-feeder that has begun feeding on Schinus or a South American Schinus-feeder that has started feeding on Rhus. Phylogenetic analysis of 800 bp of mitochondrial cytochrome oxidase I sequence data found extensive variation and phylogeographical structure within African M. transvaalensis. Specimens from other locations around the world were all identical in COI sequence and were phylogenetically nested within the African samples. We conclude that M. transvaalensis was originally an African Rhus-feeder that readily attacks Schinus. We evaluate potential pathways of introduction of this wasp to the New World, and we discuss implications of our results for biocontrol efforts against invasive Schinus populations.

Africa↗

PubMed2001

Ozone air quality over north america: part II--an analysis of trend detection and attribution techniques.

Assessment of regulatory programs aimed at improving ambient O3 air quality is of considerable interest to the scientific community and to policymakers. Trend detection, the identification of statistically significant long-term changes, and attribution, linking change to specific climatological and anthropogenic forcings, are instrumental to this assessment. Detection and attribution are difficult because changes in pollutant concentrations of interest to policymakers may be much smaller than natural variations due to weather and climate. In addition, there are considerable differences in reported trends seemingly based on similar statistical methods and databases. Differences arise from the variety of techniques used to reduce nontrend variation in time series, including mitigating the effects of meteorology and the variety of metrics used to track changes. In this paper, we review the trend assessment techniques being used in the air pollution field and discuss their strengths and limitations in discerning and attributing changes in O3 to emission control policies.

Air Pollutants↗

PubMed2004

Multigene phylogenies of Ophiostoma clavigerum and closely related species from bark beetle-attacked Pinus in North America.

Leptographium pyrinum, Leptographium terebrantis, Ophiostoma aureum, Ophiostoma clavigerum, and Ophiostoma robustum are very similar in morphology, host trees choice, and the way they are disseminated by bark beetles. Their phylogenetic relationships were clarified using rDNA and protein coding genes including actin, beta-tubulin, and translation elongation factor-1alpha. Protein coding gene trees showed better resolution than the rDNA tree, which generated three clades: O. clavigerum, L. terebrantis/L. pyrinum, and O. robustum/O. aureum. A combined gene phylogenetic tree, which was supported by high bootstrap values, showed that O. aureum, L. pyrinum, O. robustum, and O. clavigerum each formed distinct clades while L. terebrantis was paraphyletic to O. clavigerum. The higher variability of the protein coding genes and the congruity in their phylogenetic results suggested that these genes may be better markers for identifying closely related species. These gene trees have also facilitated the description of the evolutionary relationships among these species.

Actins↗

PubMed2005

Familial occurrence of Kawasaki syndrome in North America.

OBJECTIVE: To describe families with multiple members affected with Kawasaki syndrome (KS) to increase awareness of the familial occurrence of KS among practitioners who care for these patients. DESIGN: Retrospective review of medical records at 2 medical centers and data collection from remote KS families who contacted the KS Research Program at the University of California, San Diego. RESULTS: Eighteen families with multiple affected members were identified. There were 9 families with 2 affected siblings. In San Diego, 3 (0.7%) of 424 KS families had sibling cases. Nine families were identified with KS in 2 generations or in multiple affected members, yielding a total of 24 KS-affected children. No clear pattern of inheritance could be deduced from these pedigrees, and it is likely that multiple polymorphic alleles influence KS susceptibility. CONCLUSION: Physicians should counsel affected families and make them aware of the potential increased risk of KS among family members.

Adolescent↗

PubMed1994

A 4-year survey of antimicrobial susceptibility trends for isolates from cattle with bovine respiratory disease in North America.

The antimicrobial susceptibility trends of bovine respiratory disease (BRD) pathogens isolated from 1988 to 1992 were determined. A total of 880 isolates representing Pasteurella haemolytica, Pasteurella multocida, and Haemophilus somnus were used in the study. Overall, resistance to ampicillin, tetracycline, erythromycin, and sulfamethazine was frequently encountered among strains of P. haemolytica and P. multocida. Ceftiofur, an extended-spectrum cephalosporin originally marketed in 1988 for the treatment of BRD, was very active against the BRD pathogens tested; the MIC of ceftiofur for 90% of isolates tested was < or = 0.06 microgram/ml. Resistance to spectinomycin varied on the basis of the breakpoint used. Substantial variation in the year-to-year susceptibility of BRD pathogens to tilmicosin, a new macrolide antimicrobial agent, was observed. The proportion of susceptible P. haemolytica isolates ranged from 84.7% in the second year to 7.1% in the third year and 78.2% in the fourth year. Similar fluctuations were observed with strains of P. multocida.

Animals↗

PubMed2000

The evolution of Shriners Hospitals for Children in North America.

Shriners Hospitals for Children have been providing totally free care to children with neuromusculoskeletal disabilities since 1922. This mission expanded in 1962 to include the care of children with burn injuries and expanded in 1978 to include children with spinal cord injuries. Today, Shriners Hospitals for Children include 19 hospitals that provide pediatric orthopaedic care, four hospitals that provide acute and reconstructive burn care, and three hospitals in which spinal cord injury rehabilitation centers are located. During the past 20 years, case acuity and complexity have increased, comprehensiveness of care has been emphasized, members of the medical staff have increasingly become full-time, and sponsored intramural research has increased to a budget of $22 million annually. Annually, more than 250 orthopaedic residents receive pediatric orthopaedic training and more than 150 surgical residents are trained in pediatric burn care in Shriners Hospitals. In 1998, approximately 25,000 children were admitted for care, more than 22,000 operations were performed, and 236,000 children were treated as outpatients. In 1999, the annual operating budget for Shriners Hospitals for Children was $397 million.

Burns↗

PubMed2006

Obesity, dyslipidemias and erectile dysfunction: a report of a subcommittee of the sexual medicine society of North America.

Because of increasingly sedentary lifestyles and diets higher in saturated fats, obesity and dyslipidemias are common and increasing in prevalence in Westernized countries. Longitudinal population-based studies clearly demonstrate that dyslipidemias and obesity, as well as factors such as hypertension, diabetes, and smoking, are major risk factors for atherosclerosis. Both clinical and animal models of endothelial dysfunction confirm that atherosclerosis leads to increased cerebrovascular and cardiovascular morbidity. Clinical studies with hypolipidemic agents demonstrate that hydroxy-3-methylglutaryl coenzyme A reductase inhibitors can decrease the risk of vascular morbidity. An increasing body of evidence from animal models demonstrates that hypercholesterolemia and atherosclerosis are risk factors for the development of erectile dysfunction (ED). This causal relationship between obesity and dyslipidemias with the development of ED in humans still needs further definition with convincing peer-reviewed scientific studies. The challenge for the future will be to define the benefit of controlling obesity and dyslipidemias on the development of ED and improvement of erectile function.

Animals↗

PubMed1975

Tick-borne viruses associated with seabirds in North America and related islands.

About 18 tickborne viruses associated with seabirds are known from Canada, Mexico, the Antilles, and the United States, including its oceanic islands. Antigenic groups to which these viruses belong are Hughes, B, Sakhalin, Uukuniemi, Kemerovo, Nyamani and Quaranfil. Members of the last two groups are known in the Western Hemisphere only from Central Pacific Islands and may reflect intrusion of elements of the Australian Region. In the areas under discussion, antibody surveys have been minimal, but there is some indication of human exposure to agents of the Kemerovo group. Members of the Hughes, Nyamanini, and Quaranfil groups are all argasid tick viruses, largely tropical or subtropical in distribution, and associated particularly with gulls and terns (Laridae). The remainder, with the exception of Mono Lake (Kemerovo group, Chenuda Subgroup), which may be a virus of inland birds, are ixodid tick viruses associated mostly with seabirds of the polar or subpolar regions. All of these viruses are seen as acted upon by a common pattern of geographic and biotic factors that influences antigenic diversity of the virus and favors development of strong insular variants.

Animals↗

PubMed1995

Prevalence of Bartonella henselae antibodies in pet cats throughout regions of North America.

Cat exposure has been directly associated with the development of human Bartonella henselae infections, resulting in cat-scratch disease, bacillary angiomatosis, or bacteremia. The prevalence of serum antibody titers to B. henselae was determined for selected pet cats from 33 geographic locations throughout the United States and several areas in western Canada. Seroprevalences paralleled increasing climatic warmth (P < .02) and annual precipitation (P < .03). These warm, humid areas with the highest seroprevalence would also have the highest number of potential arthropod vectors. The southeastern United States, Hawaii, coastal California, the Pacific Northwest, and the south central plains had the highest average prevalences (54.6%, 47.4%, 40.0%, 34.3%, and 36.7%, respectively). Alaska, the Rocky Mountain-Great Plains region, and the Midwest had low average prevalences (5.0%, 3.7%, and 6.7%, respectively). Overall, 27.9% (175/628) of the cats tested were seropositive. The seroprevalence of B. henselae in cats varies throughout the United States and appears to be influenced by climate.

Animals↗