Cytological approaches to simuliid biosystematics in relation to the epidemiology and control of human onchocerciasis

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 559-569 ◽  
Author(s):  
W. S. Procunier
Keyword(s):  
Latin America ◽  
Species Identification ◽  
New World ◽  
Management Strategies ◽  
Resistance Management ◽  
Systematic Theory ◽  
Simulium Damnosum ◽  
Evolution Of Resistance ◽  
Age Grading ◽  
And Control

This paper presents an overview of advances in cytological research on the biosystematics of vector simuliid complexes in the areas of identification, age grading, and the evolution of resistance in relation to the epidemiology and control of human onchocerciasis. Systematic theory is discussed and relevant examples are given to show its application in predicting and resolving current problems in species identification for New World and Old World vector complexes. These complexes include Simulium damnosum s.l. and S. neavei s.l. from Africa and S. exiguum s.l., S. metallicum s.l., S. ochraceum s.l., and S. oyapockense s.l. from Latin America. The evolution of resistance in S. damnosum s.l. and the need for future molecular research as part of resistance management strategies are discussed.Key words: cytotaxonomy, systematic theory, vector simuliid complexes, resistance, onchocerciasis.

Fitness Penalties in the Evolution of Fungicide Resistance

2018 ◽  
Vol 56 (1) ◽  
pp. 339-360 ◽  
Author(s):  
N.J. Hawkins ◽  
B.A. Fraaije
Keyword(s):  
Fungicide Resistance ◽  
Management Strategies ◽  
Crop Protection ◽  
Resistance Management ◽  
Nutrient Status ◽  
Selective Advantage ◽  
Life Cycle Stage ◽  
Epistatic Interactions ◽  
Resistance Risk ◽  
Evolution Of Resistance

The evolution of resistance poses an ongoing threat to crop protection. Fungicide resistance provides a selective advantage under fungicide selection, but resistance-conferring mutations may also result in fitness penalties, resulting in an evolutionary trade-off. These penalties may result from the functional constraints of an evolving target site or from the resource allocation costs of overexpression or active transport. The extent to which such fitness penalties are present has important implications for resistance management strategies, determining whether resistance persists or declines between treatments, and for resistance risk assessments for new modes of action. Experimental results have proven variable, depending on factors such as temperature, nutrient status, osmotic or oxidative stress, and pathogen life-cycle stage. Functional genetics tools allow pathogen genetic background to be controlled, but this in turn raises the question of epistatic interactions. Combining fitness penalties under various conditions into a field-realistic scenario poses an important future challenge.

U.S. Farmer Awareness of Glyphosate-Resistant Weeds and Resistance Management Strategies

2009 ◽  
Vol 23 (2) ◽  
pp. 308-312 ◽  
Author(s):  
William G. Johnson ◽  
Micheal D. K. Owen ◽  
Greg R. Kruger ◽  
Bryan G. Young ◽  
David R. Shaw ◽  
...  
Keyword(s):  
North Carolina ◽  
Weed Control ◽  
Cropping Systems ◽  
Management Strategies ◽  
Resistance Management ◽  
Genetically Engineered ◽  
Effective Strategy ◽  
Weed Science ◽  
Evolution Of Resistance

A survey of farmers from six U.S. states (Indiana, Illinois, Iowa, Nebraska, Mississippi, and North Carolina) was conducted to assess the farmers' views on glyphosate-resistant (GR) weeds and tactics used to prevent or manage GR weed populations in genetically engineered (GE) GR crops. Only 30% of farmers thought GR weeds were a serious issue. Few farmers thought field tillage and/or using a non-GR crop in rotation with GR crops would be an effective strategy. Most farmers did not recognize the role that the recurrent use of an herbicide plays in evolution of resistance. A substantial number of farmers underestimated the potential for GR weed populations to evolve in an agroecosystem dominated by glyphosate as the weed control tactic. These results indicate there are major challenges that the agriculture and weed science communities must face to implement long-term sustainable GE GR-based cropping systems within the agroecosystem.

scholarly journals The Rapid Evolution of Resistance to Vip3Aa Insecticidal Protein in Mythimna separata (Walker) Is Not Related to Altered Binding to Midgut Receptors

Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 364
Author(s):  
Yudong Quan ◽  
Jing Yang ◽  
Yueqin Wang ◽  
Patricia Hernández-Martínez ◽  
Juan Ferré ◽  
...  
Keyword(s):  
Management Strategies ◽  
Quantitative Difference ◽  
Rapid Evolution ◽  
Resistance Management ◽  
Membrane Vesicles ◽  
Membrane Receptors ◽  
Cross Resistance ◽  
Mythimna Separata ◽  
Laboratory Selection ◽  
Evolution Of Resistance

Laboratory selection for resistance of field populations is a well-known and useful tool to understand the potential of insect populations to evolve resistance to insecticides. It provides us with estimates of the frequency of resistance alleles and allows us to study the mechanisms by which insects developed resistance to shed light on the mode of action and optimize resistance management strategies. Here, a field population of Mythimna separata was subjected to laboratory selection with either Vip3Aa, Cry1Ab, or Cry1F insecticidal proteins from Bacillus thuringiensis. The population rapidly evolved resistance to Vip3Aa reaching, after eight generations, a level of >3061-fold resistance, compared with the unselected insects. In contrast, the same population did not respond to selection with Cry1Ab or Cry1F. The Vip3Aa resistant population did not show cross resistance to either Cry1Ab or Cry1F. Radiolabeled Vip3Aa was tested for binding to brush border membrane vesicles from larvae from the susceptible and resistant insects. The results did not show any qualitative or quantitative difference between both insect samples. Our data, along with previous results obtained with other Vip3Aa-resistant populations from other insect species, suggest that altered binding to midgut membrane receptors is not the main mechanism of resistance to Vip3Aa.

scholarly journals Are Efficient-Dose Mixtures a Solution to Reduce Fungicide Load and Delay Evolution of Resistance? An Experimental Evolutionary Approach

2021 ◽  
Vol 9 (11) ◽  
pp. 2324
Author(s):  
Agathe Ballu ◽  
Anne Deredec ◽  
Anne-Sophie Walker ◽  
Florence Carpentier
Keyword(s):  
Fungal Pathogen ◽  
Management Strategies ◽  
Resistance Management ◽  
Mixture Component ◽  
Pesticide Resistance ◽  
Susceptible Population ◽  
Minimal Dose ◽  
Full Control ◽  
Evolution Of Resistance ◽  
Continuous Use

Pesticide resistance poses a critical threat to agriculture, human health and biodiversity. Mixtures of fungicides are recommended and widely used in resistance management strategies. However, the components of the efficiency of such mixtures remain unclear. We performed an experimental evolutionary study on the fungal pathogen Z. tritici to determine how mixtures managed resistance. We compared the effect of the continuous use of single active ingredients to that of mixtures, at the minimal dose providing full control of the disease, which we refer to as the “efficient” dose. We found that the performance of efficient-dose mixtures against an initially susceptible population depended strongly on the components of the mixture. Such mixtures were either as durable as the best mixture component used alone, or worse than all components used alone. Moreover, efficient dose mixture regimes probably select for generalist resistance profiles as a result of the combination of selection pressures exerted by the various components and their lower doses. Our results indicate that mixtures should not be considered a universal strategy. Experimental evaluations of specificities for the pathogens targeted, their interactions with fungicides and the interactions between fungicides are crucial for the design of sustainable resistance management strategies.

scholarly journals Why do fungicide mixtures delay the evolution of resistance? An experimental evolutionary approach

2021 ◽  
Author(s):  
Agathe Ballu ◽  
Anne Deredec ◽  
Anne-Sophie Walker ◽  
Florence Carpentier
Keyword(s):  
Management Strategies ◽  
Resistance Management ◽  
Mixture Component ◽  
Susceptible Population ◽  
Minimal Dose ◽  
Full Control ◽  
Fungicide Mixtures ◽  
Evolution Of Resistance ◽  
Evolution Study ◽  
Continuous Use

Pesticide resistance poses a critical threat to agriculture, human health and biodiversity. Mixtures of fungicides are recommended and widely used in resistance management strategies. However, the components of the efficiency of such mixtures remain unclear. We performed an experimental evolution study on the fungal pathogen Z. tritici, to determine how mixtures managed resistance. We compared the effect of the continuous use of single active ingredients to that of mixtures, at the minimal dose providing full control of the disease, which we refer to as the "efficient" dose. We found that the performance of efficient-dose mixtures against an initially susceptible population depended strongly on the components of the mixture. Such mixtures were either as durable as the best mixture component used alone, or worse than all components used alone. Moreover, efficient-dose mixture regimes probably select for generalist resistance profiles as a result of the combination of selection pressures exerted by the various components and their lower doses. Our results indicate that mixtures should not be considered a universal strategy. Experimental evaluations of specificities for the pathogens targeted, their interactions with fungicides and the interactions between fungicides are crucial for the design of sustainable resistance management strategies.

Epidemiology of Hypertension and Diabetes Mellitus in Latin America

2020 ◽  
Vol 16 ◽  
Author(s):  
Patricio Lopez-Jaramillo ◽  
Jose Lopez-Lopez ◽  
Daniel Cohen ◽  
Natalia Alarcon-Ariza ◽  
Margarita Mogollon-Zehr
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 2 Diabetes Mellitus ◽  
Latin America ◽  
Cardiovascular Diseases ◽  
Latin American ◽  
Premature Mortality ◽  
Increased Risk ◽  
And Control

: Hypertension and type 2 diabetes mellitus are two important risk factors that contribute to cardiovascular diseases worldwide. In Latin America hypertension prevalence varies from 30 to 50%. Moreover, the proportion of awareness, treatment and control of hypertension is very low. The prevalence of type 2 diabetes mellitus varies from 8 to 13% and near to 40% are unaware of their condition. In addition, the prevalence of prediabetes varies from 6 to 14% and this condition has been also associated with increased risk of cardiovascular diseases. The principal factors linked to a higher risk of hypertension in Latin America are increased adiposity, low muscle strength, unhealthy diet, low physical activity and low education. Besides being chronic conditions, leading causes of cardiovascular mortality, both hypertension and type 2 diabetes mellitus represent a substantial cost for the weak health systems of Latin American countries. Therefore, is necessary to implement and reinforce public health programs to improve awareness, treatment and control of hypertension and type 2 diabetes mellitus, in order to reach the mandate of the Unit Nations of decrease the premature mortality for CVD.

scholarly journals 766. Everything Old is New Again-A Case Series of New World Leishmaniasis in African Children in Portland, Maine

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S428-S428
Author(s):  
Jennifer Jubulis ◽  
Amanda Goddard ◽  
Elizabeth Seiverling ◽  
Marc Kimball ◽  
Carol A McCarthy
Keyword(s):  
Latin America ◽  
Cutaneous Leishmaniasis ◽  
New World ◽  
Pediatric Patients ◽  
Data Extraction ◽  
Clinical Manifestations ◽  
Case Series ◽  
Surgical Excision ◽  
Skin Lesions ◽  
Travel History

Abstract Background Leishmaniasis has many clinical manifestations and treatment regimens, dependent on species and host. Old world leishmaniasis is found primarily in Africa and Asia, and is associated with visceral disease, while new world disease, seen primarily in Latin America, is more commonly mucocutaneous. We present a case series of pediatric African patients with New World cutaneous leishmaniasis (NWCL). Methods Data extraction was performed via chart review, analyzing travel history, clinical presentation, diagnosis, and management in children with cutaneous leishmaniasis presenting to the pediatric infectious diseases clinic in Portland, ME. Biopsy specimens were sent to the federal CDC for identification by PCR and culture. Results Five cases of NWCL were diagnosed in pediatric patients in Maine from November 2018 through February 2020. Median age of patients was 10 years (range 1.5-15 years). Four cases (80%) occurred in children from Angola or Democratic Republic of Congo, arriving in Maine via Central/South America, with one case in a child from Rwanda who arrived in Maine via Texas. Three patients had multiple skin lesions and two had isolated facial lesions. Leishmaniasis was not initially suspected resulting in median time to diagnosis of 5 months (range 1-7 months). Four patients were initially treated with antibacterials for cellulitis and one was treated with griseofulvin. After no improvement, patients underwent biopsy with 2 patients diagnosed with L panamensis, 1 with L braziliensis, 1 with mixed infection (L panamensis and L mexicana), and 1 with Leishmania species only. One patient was managed with surgical excision, 3 with ketoconazole, and 1 was observed off therapy. Four patients were referred to otolaryngology. All continue to be followed in infectious disease clinic. Conclusion We present five cases of new world cutaneous leishmaniasis in African pediatric patients arriving to Maine through Latin America or Texas. Patients were diagnosed with cellulitis, tinea corporis or atopic dermatitis initially, underscoring importance of high index of suspicion in migrant patients. Detailed travel history and epidemiologic knowledge is essential to diagnosis, as patients may present with illness not congruent with country of origin. Optimal therapy remains unclear. Disclosures All Authors: No reported disclosures

scholarly journals Latin America in Global History: An Historiographic Overview

2017 ◽  
Vol 30 (60) ◽  
pp. 253-272 ◽  
Author(s):  
Diego Olstein
Keyword(s):  
Latin America ◽  
Sixteenth Century ◽  
New World ◽  
World History ◽  
The Other ◽  
Ice Age ◽  
Global History ◽  
The World ◽  
Last Ice Age ◽  
Great Divergence

Abstract World history can be arranged into three major regional divergences: the 'Greatest Divergence' starting at the end of the last Ice Age (ca. 15,000 years ago) and isolating the Old and the New Worlds from one another till 1500; the 'Great Divergence' bifurcating the paths of Europe and Afro-Asia since 1500; and the 'American Divergence' which divided the fortunes of New World societies from 1500 onwards. Accordingly, all world regions have confronted two divergences: one disassociating the fates of the Old and New Worlds, and the other within either the Old or the New World. Latin America is in the uneasy position that in both divergences it ended up on the 'losing side.' As a result, a contentious historiography of Latin America evolved from the very moment that it was incorporated into the wider world. Three basic attitudes toward the place of Latin America in global history have since emerged and developed: admiration for the major impact that the emergence on Latin America on the world scene imprinted on global history; hostility and disdain over Latin America since it entered the world scene; direct rejection of and head on confrontation in reaction the former. This paper examines each of these three attitudes in five periods: the 'long sixteenth century' (1492-1650); the 'age of crisis' (1650-1780); 'the long nineteenth century' (1780-1914); 'the short twentieth century' (1914-1991); and 'contemporary globalization' (1991 onwards).

Language as a Key to Latin American Historiography

1955 ◽  
Vol 11 (4) ◽  
pp. 517-539
Author(s):  
Richard M. Morse
Keyword(s):  
Latin America ◽  
Latin American ◽  
New World ◽  
Old World ◽  
History Of

Latin americanists have in recent years become increasingly concerned with constructing the basis for a unified history of Latin America. Frequently this enterprise leads them to contemplate the even larger design of a history of the Americas. While the New World may still be, in Hegel’s words, “a land of desire for all those who are weary of the historical lumber-room of old Europe,” it is now recognized as having an independent heritage; its history is no longer experienced as “only an echo of the Old World.”

Environmental impact and risk management strategies of Bt cotton commercialization in China

2007 ◽  
Vol 4 (2) ◽  
pp. 93-97 ◽  
Author(s):  
Wu Kong-Ming
Keyword(s):  
Risk Management ◽  
Environmental Impact ◽  
Management Strategies ◽  
Cotton Bollworm ◽  
Bt Cotton ◽  
Resistance Risk ◽  
Factors Associated ◽  
Major Threat ◽  
Risk Management Strategies ◽  
Evolution Of Resistance

AbstractTransgenic cotton expressing the Cry1Ac toxin from Bacillus thuringiensis has been planted widely in China since 1997, and reached 70% of the total cotton area in 2006. The results of monitoring the environmental impact of Bt cotton commercialization indicated that the target pests, cotton bollworm (Helicoverpa armigera) and pink bollworm (Pectinophora gossypiella), were effectively controlled while the mirids (Hemiptera: Miridae) evolved to be key pests in the cotton system. There were no significant changes in resistance gene frequency of field populations of cotton bollworm, but a shift toward increased tolerance was apparent in the area of intensive planting of Bt cotton, indicating that the potential risk of resistance of the target pest has become a major threat for sustainable planting of Bt cotton. Considering the factors associated with the evolution of resistance, risk management strategies are discussed in this paper.

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