scholarly journals Temporal variation in genetic structure of a colonising species: Aedes albopictus in the United States

Heredity ◽  
1990 ◽  
Vol 64 (2) ◽  
pp. 281-287 ◽  
Author(s):  
Srinivas Kambhampati ◽  
William C Black ◽  
Karamjit S Rai ◽  
Daniel Sprenger
Keyword(s):  
United States ◽  
Genetic Structure ◽  
Temporal Variation ◽  
Aedes Albopictus ◽  
The United States

scholarly journals Genetic Structure and Molecular Variability of Cucumber mosaic virus Isolates in the United States

PLoS ONE ◽  
2014 ◽  
Vol 9 (5) ◽  
pp. e96582 ◽  
Author(s):  
Shahideh Nouri ◽  
Rafael Arevalo ◽  
Bryce W. Falk ◽  
Russell L. Groves
Keyword(s):  
United States ◽  
Genetic Structure ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
The United States ◽  
Molecular Variability ◽  
Virus Isolates

scholarly journals Migration Patterns of the Emerging Plant Pathogen Phytophthora ramorum on the West Coast of the United States of America

2009 ◽  
Vol 99 (6) ◽  
pp. 739-749 ◽  
Author(s):  
S. Prospero ◽  
N. J. Grünwald ◽  
L. M. Winton ◽  
E. M. Hansen
Keyword(s):  
United States ◽  
Genetic Structure ◽  
West Coast ◽  
Large Scale ◽  
Reproductive Mode ◽  
The United States ◽  
Phytophthora Ramorum ◽  
The West ◽  
Migration Patterns ◽  
High Incidence

Phytophthora ramorum (oomycetes) is the causal agent of sudden oak death and ramorum blight on trees, shrubs, and woody ornamentals in the forests of coastal California and southwestern Oregon and in nurseries of California, Oregon, and Washington. In this study, we investigated the genetic structure of P. ramorum on the West Coast of the United States, focusing particularly on population differentiation potentially indicative of gene flow. In total, 576 isolates recovered from 2001 to 2005 were genotyped at 10 microsatellite loci. Our analyses of genetic diversity and inferences of reproductive mode confirm previous results for the Oregon and California populations, with the strong majority of the genotypes belonging to the NA1 clonal lineage and showing no evidence for sexual reproduction. The high incidence of genotypes shared among populations and the lack of genetic structure among populations show that important large-scale, interpopulation genetic exchanges have occurred. This emphasizes the importance of human activity in shaping the current structure of the P. ramorum population on the West Coast of the United States.

scholarly journals Shifting Genetic Structure of Invasive Serotype 19A Pneumococci in the United States

2011 ◽  
Vol 203 (10) ◽  
pp. 1360-1368 ◽  
Author(s):  
Bernard W. Beall ◽  
Robert E. Gertz ◽  
Rachel L. Hulkower ◽  
Cynthia G. Whitney ◽  
Matthew R. Moore ◽  
...  
Keyword(s):  
United States ◽  
Genetic Structure ◽  
The United States

scholarly journals Genetic Structure and Analysis of Host and Nonhost Interactions of Striga gesnerioides (Witchweed) from Central Florida

2005 ◽  
Vol 95 (10) ◽  
pp. 1166-1173 ◽  
Author(s):  
Christopher J. Botanga ◽  
Michael P. Timko
Keyword(s):  
United States ◽  
Genetic Structure ◽  
West Africa ◽  
The United States ◽  
Genetic Distances ◽  
Polymorphism Analysis ◽  
Root Hemiparasite ◽  
Striga Gesnerioides ◽  
Central Florida ◽  
High Level

Striga gesnerioides is a root hemiparasite of wild and cultivated legumes, among which cowpea (Vigna unguiculata) and Indigofera hirsuta are suitable hosts. In this study, we examined the genetic structure and host-parasite interaction of a strain of S. gesnerioides parasitizing I. hirsuta (SGFL) from central Florida (United States). Amplified fragment length polymorphism analysis was used to compare genetic profiles from 71 individual S. gesnerioides plants (SGFL) representing four different populations in central Florida. Our results showed that these individuals are genetically similar, with pairwise genetic distances ranging from 0.00 to 0.037. A cluster analysis grouped all four S. gesnerioides populations from Florida, separating them from S. gesnerioides isolates parasitic on I. hirsuta and cowpea collected from West Africa. One EcoRI and MseI selective primer combination generated a 510-bp fragment present in individuals from the SGFL and the West African isolate parasitic on I. hirsuta, but absent in isolates parasitic on cowpea. Germination of seed from individuals of all four populations of S. gesnerioides parasitic on I. hirsuta from Florida was stimulated by root exudates from cowpea genotypes Blackeye and TVX-3236, known to be highly susceptible to all races of S. gesnerioides parasitic on cowpea in West Africa. SGFL seedlings failed to parasitize cowpea, with the development of attached SGFL seedlings arrested at the tubercle stage. The very high level of genetic uniformity observed within and among the central Florida populations suggests that there was likely a single introduction of the parasite or strong host-driven selection to genetic uniformity.These findings are important in assessing the potential of the parasite as an agronomically significant pest in the United States.

scholarly journals Spatial and Temporal Variation in PM 2.5 Chemical Composition in the United States for Health Effects Studies

2007 ◽  
Vol 115 (7) ◽  
pp. 989-995 ◽  
Author(s):  
Michelle L. Bell ◽  
Francesca Dominici ◽  
Keita Ebisu ◽  
Scott L. Zeger ◽  
Jonathan M. Samet
Keyword(s):  
United States ◽  
Chemical Composition ◽  
Temporal Variation ◽  
Health Effects ◽  
The United States ◽  
Spatial And Temporal Variation ◽  
Pm 2.5

scholarly journals The Effect of Stay-at-Home Orders on COVID-19 Infections in the United States

2020 ◽  
Author(s):  
James H. Fowler ◽  
Seth J. Hill ◽  
Remy Levin ◽  
Nick Obradovich
Keyword(s):  
United States ◽  
Temporal Variation ◽  
Fixed Effects ◽  
National Level ◽  
The United States ◽  
Spatial And Temporal Variation ◽  
Full Potential ◽  
County Level ◽  
Fixed Effects Model ◽  
At Home

SummaryBackgroundIn March and April 2020, public health authorities in the United States acted to mitigate transmission of and hospitalizations from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19). These actions were not coordinated at the national level, which raises the question of what might have happened if they were. It also creates an opportunity to use spatial and temporal variation to measure their effect with greater accuracy.MethodsWe combine publicly available data sources on the timing of stay-at-home orders and daily confirmed COVID-19 cases at the county level in the United States (N = 124,027). We then derive from the classic SIR model a two-way fixed-effects model and apply it to the data with controls for unmeasured differences between counties and over time. This enables us to estimate the effect of stay-at-home orders while accounting for local variation in factors like health systems and demographics, and temporal variation in national mitigation actions, access to tests, or exposure to media reports that could influence the course of the disease.FindingsMean county-level daily growth in COVID-19 infections peaked at 17.2% just before stay-at-home orders were issued. Two way fixed-effects regression estimates suggest that orders were associated with a 3.9 percentage point (95% CI 1.2 to 6.6) reduction in the growth rate after one week and a 6.9 percentage point (2.4 to 11.5) reduction after two weeks. By day 27 the reduction (22.6 percentage points, 14.8 to 30.5) had surpassed the growth at the peak, indicating that growth had turned negative and the number of new daily infections was beginning to decline. A hypothetical national stay-at-home order issued on March 13, 2020 when a national emergency was declared might have reduced cumulative infections by 63.3%, and might have helped to reverse exponential growth in the disease by April 10.InterpretationAlthough stay-at-home orders impose great costs to society, delayed responses and piecemeal application of these orders generate similar costs without obtaining the full potential benefits suggested by this analysis. The results here suggest that a coordinated nationwide stay-at-home order might have reduced by hundreds of thousands the current number of infections and by tens of thousands the total number of deaths from COVID-19. Future efforts in the United States and elsewhere to control pandemics should coordinate stay-at-home orders at the national level, especially for diseases for which local spread has already occurred and testing availability is delayed. Since stay-at-home orders reduce infection growth rates, early implementation when infection counts are still low would be most beneficial.FundingNone.

scholarly journals Environmental Determinants of Aedes albopictus Abundance at a Northern Limit of Its Range in the United States

2020 ◽  
Vol 102 (2) ◽  
pp. 436-447
Author(s):  
Pallavi A. Kache ◽  
Gillian Eastwood ◽  
Kaitlin Collins-Palmer ◽  
Marly Katz ◽  
Richard C. Falco ◽  
...  
Keyword(s):  
United States ◽  
Aedes Albopictus ◽  
The United States ◽  
Environmental Determinants ◽  
Northern Limit

scholarly journals Stay-at-home orders associate with subsequent decreases in COVID-19 cases and fatalities in the United States

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0248849
Author(s):  
James H. Fowler ◽  
Seth J. Hill ◽  
Remy Levin ◽  
Nick Obradovich
Keyword(s):  
United States ◽  
Temporal Variation ◽  
National Level ◽  
Local Variation ◽  
The United States ◽  
Spatial And Temporal Variation ◽  
Difference In Differences ◽  
Contagious Diseases ◽  
Incident Cases ◽  
At Home

Governments issue “stay-at-home” orders to reduce the spread of contagious diseases, but the magnitude of such orders’ effectiveness remains uncertain. In the United States these orders were not coordinated at the national level during the coronavirus disease 2019 (COVID-19) pandemic, which creates an opportunity to use spatial and temporal variation to measure the policies’ effect. Here, we combine data on the timing of stay-at-home orders with daily confirmed COVID-19 cases and fatalities at the county level during the first seven weeks of the outbreak in the United States. We estimate the association between stay-at-home orders and alterations in COVID-19 cases and fatalities using a difference-in-differences design that accounts for unmeasured local variation in factors like health systems and demographics and for unmeasured temporal variation in factors like national mitigation actions and access to tests. Compared to counties that did not implement stay-at-home orders, the results show that the orders are associated with a 30.2 percent (11.0 to 45.2) average reduction in weekly incident cases after one week, a 40.0 percent (23.4 to 53.0) reduction after two weeks, and a 48.6 percent (31.1 to 61.7) reduction after three weeks. Stay-at-home orders are also associated with a 59.8 percent (18.3 to 80.2) average reduction in weekly fatalities after three weeks. These results suggest that stay-at-home orders might have reduced confirmed cases by 390,000 (170,000 to 680,000) and fatalities by 41,000 (27,000 to 59,000) within the first three weeks in localities that implemented stay-at-home orders.

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